Publications by authors named "Malinee Chittaganpitch"

62 Publications

Global burden of influenza-associated lower respiratory tract infections and hospitalizations among adults: A systematic review and meta-analysis.

PLoS Med 2021 Mar 1;18(3):e1003550. Epub 2021 Mar 1.

Division of Global Health Protection, US Centers for Disease Control and Prevention, Nairobi, Kenya.

Background: Influenza illness burden is substantial, particularly among young children, older adults, and those with underlying conditions. Initiatives are underway to develop better global estimates for influenza-associated hospitalizations and deaths. Knowledge gaps remain regarding the role of influenza viruses in severe respiratory disease and hospitalizations among adults, particularly in lower-income settings.

Methods And Findings: We aggregated published data from a systematic review and unpublished data from surveillance platforms to generate global meta-analytic estimates for the proportion of acute respiratory hospitalizations associated with influenza viruses among adults. We searched 9 online databases (Medline, Embase, CINAHL, Cochrane Library, Scopus, Global Health, LILACS, WHOLIS, and CNKI; 1 January 1996-31 December 2016) to identify observational studies of influenza-associated hospitalizations in adults, and assessed eligible papers for bias using a simplified Newcastle-Ottawa scale for observational data. We applied meta-analytic proportions to global estimates of lower respiratory infections (LRIs) and hospitalizations from the Global Burden of Disease study in adults ≥20 years and by age groups (20-64 years and ≥65 years) to obtain the number of influenza-associated LRI episodes and hospitalizations for 2016. Data from 63 sources showed that influenza was associated with 14.1% (95% CI 12.1%-16.5%) of acute respiratory hospitalizations among all adults, with no significant differences by age group. The 63 data sources represent published observational studies (n = 28) and unpublished surveillance data (n = 35), from all World Health Organization regions (Africa, n = 8; Americas, n = 11; Eastern Mediterranean, n = 7; Europe, n = 8; Southeast Asia, n = 11; Western Pacific, n = 18). Data quality for published data sources was predominantly moderate or high (75%, n = 56/75). We estimate 32,126,000 (95% CI 20,484,000-46,129,000) influenza-associated LRI episodes and 5,678,000 (95% CI 3,205,000-9,432,000) LRI hospitalizations occur each year among adults. While adults <65 years contribute most influenza-associated LRI hospitalizations and episodes (3,464,000 [95% CI 1,885,000-5,978,000] LRI hospitalizations and 31,087,000 [95% CI 19,987,000-44,444,000] LRI episodes), hospitalization rates were highest in those ≥65 years (437/100,000 person-years [95% CI 265-612/100,000 person-years]). For this analysis, published articles were limited in their inclusion of stratified testing data by year and age group. Lack of information regarding influenza vaccination of the study population was also a limitation across both types of data sources.

Conclusions: In this meta-analysis, we estimated that influenza viruses are associated with over 5 million hospitalizations worldwide per year. Inclusion of both published and unpublished findings allowed for increased power to generate stratified estimates, and improved representation from lower-income countries. Together, the available data demonstrate the importance of influenza viruses as a cause of severe disease and hospitalizations in younger and older adults worldwide.
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http://dx.doi.org/10.1371/journal.pmed.1003550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959367PMC
March 2021

Global burden of acute lower respiratory infection associated with human metapneumovirus in children under 5 years in 2018: a systematic review and modelling study.

Lancet Glob Health 2021 01 26;9(1):e33-e43. Epub 2020 Nov 26.

Centre for Global Health, Usher Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK. Electronic address:

Background: Human metapneumovirus is a common virus associated with acute lower respiratory infections (ALRIs) in children. No global burden estimates are available for ALRIs associated with human metapneumovirus in children, and no licensed vaccines or drugs exist for human metapneumovirus infections. We aimed to estimate the age-stratified human metapneumovirus-associated ALRI global incidence, hospital admissions, and mortality burden in children younger than 5 years.

Methods: We estimated the global burden of human metapneumovirus-associated ALRIs in children younger than 5 years from a systematic review of 119 studies published between Jan 1, 2001, and Dec 31, 2019, and a further 40 high quality unpublished studies. We assessed risk of bias using a modified Newcastle-Ottawa Scale. We estimated incidence, hospital admission rates, and in-hospital case-fatality ratios (hCFRs) of human metapneumovirus-associated ALRI using a generalised linear mixed model. We applied incidence and hospital admission rates of human metapneumovirus-associated ALRI to population estimates to yield the morbidity burden estimates by age bands and World Bank income levels. We also estimated human metapneumovirus-associated ALRI in-hospital deaths and overall human metapneumovirus-associated ALRI deaths (both in-hospital and non-hospital deaths). Additionally, we estimated human metapneumovirus-attributable ALRI cases, hospital admissions, and deaths by combining human metapneumovirus-associated burden estimates and attributable fractions of human metapneumovirus in laboratory-confirmed human metapneumovirus cases and deaths.

Findings: In 2018, among children younger than 5 years globally, there were an estimated 14·2 million human metapneumovirus-associated ALRI cases (uncertainty range [UR] 10·2 million to 20·1 million), 643 000 human metapneumovirus-associated hospital admissions (UR 425 000 to 977 000), 7700 human metapneumovirus-associated in-hospital deaths (2600 to 48 800), and 16 100 overall (hospital and community) human metapneumovirus-associated ALRI deaths (5700 to 88 000). An estimated 11·1 million ALRI cases (UR 8·0 million to 15·7 million), 502 000 ALRI hospital admissions (UR 332 000 to 762 000), and 11 300 ALRI deaths (4000 to 61 600) could be causally attributed to human metapneumovirus in 2018. Around 58% of the hospital admissions were in infants under 12 months, and 64% of in-hospital deaths occurred in infants younger than 6 months, of which 79% occurred in low-income and lower-middle-income countries.

Interpretation: Infants younger than 1 year have disproportionately high risks of severe human metapneumovirus infections across all World Bank income regions and all child mortality settings, similar to respiratory syncytial virus and influenza virus. Infants younger than 6 months in low-income and lower-middle-income countries are at greater risk of death from human metapneumovirus-associated ALRI than older children and those in upper-middle-income and high-income countries. Our mortality estimates demonstrate the importance of intervention strategies for infants across all settings, and warrant continued efforts to improve the outcome of human metapneumovirus-associated ALRI among young infants in low-income and lower-middle-income countries.

Funding: Bill & Melinda Gates Foundation.
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http://dx.doi.org/10.1016/S2214-109X(20)30393-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783516PMC
January 2021

The epidemiology and estimated etiology of pathogens detected from the upper respiratory tract of adults with severe acute respiratory infections in multiple countries, 2014-2015.

PLoS One 2020 19;15(10):e0240309. Epub 2020 Oct 19.

Division of Bacterial Diseases, Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases, Atlanta, Georgia, United States of America.

Introduction: Etiology studies of severe acute respiratory infections (SARI) in adults are limited. We studied potential etiologies of SARI among adults in six countries using multi-pathogen diagnostics.

Methods: We enrolled both adults with SARI (acute respiratory illness onset with fever and cough requiring hospitalization) and asymptomatic adults (adults hospitalized with non-infectious illnesses, non-household members accompanying SARI patients, adults enrolled from outpatient departments, and community members) in each country. Demographics, clinical data, and nasopharyngeal and oropharyngeal specimens were collected from both SARI patients and asymptomatic adults. Specimens were tested for presence of 29 pathogens utilizing the Taqman® Array Card platform. We applied a non-parametric Bayesian regression extension of a partially latent class model approach to estimate proportions of SARI caused by specific pathogens.

Results: We enrolled 2,388 SARI patients and 1,135 asymptomatic adults from October 2013 through October 2015. We detected ≥1 pathogen in 76% of SARI patients and 67% of asymptomatic adults. Haemophilus influenzae and Streptococcus pneumoniae were most commonly detected (≥23% of SARI patients and asymptomatic adults). Through modeling, etiology was attributed to a pathogen in most SARI patients (range among countries: 57.3-93.2%); pathogens commonly attributed to SARI etiology included influenza A (14.4-54.4%), influenza B (1.9-19.1%), rhino/enterovirus (1.8-42.6%), and RSV (3.6-14.6%).

Conclusions: Use of multi-pathogen diagnostics and modeling enabled attribution of etiology in most adult SARI patients, despite frequent detection of multiple pathogens in the upper respiratory tract. Seasonal flu vaccination and development of RSV vaccine would likely reduce the burden of SARI in these populations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0240309PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571682PMC
December 2020

Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17.

Influenza Other Respir Viruses 2020 11 30;14(6):671-677. Epub 2020 Jul 30.

Global Influenza Programme, World Health Organization, Geneva, Switzerland.

Background: External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016-2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV.

Methods: The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT-PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories.

Results: Laboratories performed well using the CDC RSV rRT-PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false-positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs.

Conclusions: These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended.
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http://dx.doi.org/10.1111/irv.12771DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7578327PMC
November 2020

Enhanced surveillance for severe pneumonia, Thailand 2010-2015.

BMC Public Health 2019 May 10;19(Suppl 3):472. Epub 2019 May 10.

Department of Disease Control, Bureau of Epidemiology, Ministry of Public Health, Tivanond Road, Nonthaburi, 11000, Thailand.

Background: The etiology of severe pneumonia is frequently not identified by routine disease surveillance in Thailand. Since 2010, the Thailand Ministry of Public Health (MOPH) and US CDC have conducted surveillance to detect known and new etiologies of severe pneumonia.

Methods: Surveillance for severe community-acquired pneumonia was initiated in December 2010 among 30 hospitals in 17 provinces covering all regions of Thailand. Interlinked clinical, laboratory, pathological and epidemiological components of the network were created with specialized guidelines for each to aid case investigation and notification. Severe pneumonia was defined as chest-radiograph confirmed pneumonia of unknown etiology in a patient hospitalized ≤48 h and requiring intubation with ventilator support or who died within 48 h after hospitalization; patients with underlying chronic pulmonary or neurological disease were excluded. Respiratory and pathological specimens were tested by reverse transcription polymerase chain reaction for nine viruses, including Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and 14 bacteria. Cases were reported via a secure web-based system.

Results: Of specimens from 972 cases available for testing during December 2010 through December 2015, 589 (60.6%) had a potential etiology identified; 399 (67.8%) were from children aged < 5 years. At least one viral agent was detected in 394 (40.5%) cases, with the most common of single vial pathogen detected being respiratory syncytial virus (RSV) (110/589, 18.7%) especially in children under 5 years. Bacterial pathogens were detected in 341 cases of which 67 cases had apparent mixed infections. The system added MERS-CoV testing in September 2012 as part of Thailand's outbreak preparedness; no cases were identified from the 767 samples tested.

Conclusions: Enhanced surveillance improved the understanding of the etiology of severe pneumonia cases and improved the MOPH's preparedness and response capacity for emerging respiratory pathogens in Thailand thereby enhanced global health security. Guidelines for investigation of severe pneumonia from this project were incorporated into surveillance and research activities within Thailand and shared for adaption by other countries.
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http://dx.doi.org/10.1186/s12889-019-6774-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6696659PMC
May 2019

Human respiratory syncytial virus and influenza seasonality patterns-Early findings from the WHO global respiratory syncytial virus surveillance.

Influenza Other Respir Viruses 2020 11 12;14(6):638-646. Epub 2020 Mar 12.

Global Influenza Programme, World Health Organization, Geneva, Switzerland.

Background: Human respiratory syncytial virus (RSV) causes illnesses among all age groups and presents a burden to healthcare services. To better understand the epidemiology and seasonality of RSV in different geographical areas, the World Health Organization (WHO) coordinated a pilot initiative to access the feasibility of establishing RSV surveillance using the existing Global Influenza Surveillance and Response System (GISRS) platform.

Objectives: To describe and compare RSV and influenza seasonality in countries in the northern andsouthern temperate, and tropics during the period January 2017 to April 2019.

Methods: Fourteen countries in six WHO regions participating in the GISRS were invited for the pilot. Hospitalized patients presenting with severe acute respiratory illness (SARI), SARI without fever and outpatients presenting with acute respiratory illness (ARI) were enrolled from January 2017 to April 2019. The expected minimum sample size was 20 samples per week, year-round, per country. Real-time RT-PCR was used to detect RSV and influenza viruses. Results were uploaded to the WHO FluMart platform.

Results: Annual seasonality of RSV was observed in all countries, which overlapped to a large extent with the influenza activity. In countries, in temperate regions RSV peaked in the autumn/winter months. In Egypt, a subtropical country, RSV activity peaked in the cooler season. In the tropical regions, RSV peaked during the rainy seasons.

Conclusion: Early findings from the WHO RSV surveillance pilot based on the GISRS suggest annual seasonal patterns for of RSV circulation that overlap with influenza. RSV surveillance needs to be continued for several more seasons to establish seasonality patterns to inform prevention and control strategies.
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http://dx.doi.org/10.1111/irv.12726DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7578323PMC
November 2020

Early transmission patterns of coronavirus disease 2019 (COVID-19) in travellers from Wuhan to Thailand, January 2020.

Euro Surveill 2020 02;25(8)

Department of Biological Sciences, National University of Singapore, Singapore.

We report two cases of coronavirus disease 2019 (COVID-19) in travellers from Wuhan, China to Thailand. Both were independent introductions on separate flights, discovered with thermoscanners and confirmed with RT-PCR and genome sequencing. Both cases do not seem directly linked to the Huanan Seafood Market in Hubei but the viral genomes are identical to four other sequences from Wuhan, suggesting early spread within the city already in the first week of January.
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http://dx.doi.org/10.2807/1560-7917.ES.2020.25.8.2000097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7055038PMC
February 2020

Metformin-induced suppression of IFN-α via mTORC1 signalling following seasonal vaccination is associated with impaired antibody responses in type 2 diabetes.

Sci Rep 2020 02 24;10(1):3229. Epub 2020 Feb 24.

Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.

Diabetes mellitus (DM) patients are at an increased risk of complications following influenza-virus infection, seasonal vaccination (SV) is recommended. However, SV with trivalent influenza vaccine (TIV) can induce antibody and type-I interferon (IFN) responses, and the effect of anti-DM treatment on these responses is incompletely understood. We evaluated the antibody response and IFN-α expression in individuals with and without type 2 DM (T2DM) following SV, and examined the effects on anti-DM treatment. TIV elicited sero-protection in all groups, but antibody persistency was <8 months, except for the antibody response to B-antigens in non-DM. T2DM impaired the IgG avidity index, and T2DM showed a significantly decreased response against H1N1 and H3N2, in addition to delaying and reducing haemagglutination-inhibition persistency against influenza B-antigens in DM groups treated with metformin (Met-DM) or glibenclamide (GB-DM). Following TIV, the Met-DM and GB-DM groups exhibited reduced IFN-α expression upon stimulation with whole- and split-virion influenza vaccines. Suppression of IFN-α expression in the Met-DM group was associated with a reduction in the mechanistic target of rapamycin complex-1 pathway and impaired IgG avidity index. Thus, single-dose TIV each year might not be suitable for T2DM. Our data could aid the development of an efficacious influenza vaccine for T2DM.
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http://dx.doi.org/10.1038/s41598-020-60213-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039947PMC
February 2020

Immune response to influenza vaccination in ESRD patients undergoing hemodialysis vs. hemodiafiltration.

PLoS One 2020 3;15(2):e0227719. Epub 2020 Feb 3.

Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.

Background: On-line hemodiafiltration (HDF) clears more azotemic toxins compared to high-flux hemodialysis (HD). The response to vaccination is impaired in dialysis patients. We wished to determine whether the immune responses to influenza vaccine in dialysis patients treated by HDF were stronger than those treated by HD.

Materials And Methods: We conducted a prospective cohort study in chronic dialysis patients during the 2016 and 2017 influenza seasons. All participants received a single standard dose of trivalent influenza vaccine, and we studied the elicited humoral immune response by hemagglutination inhibition test, and cell-mediated immune response by enumeration of lymphocyte cellular markers and proliferation assays.

Results: We immunized 60 end-stage renal disease (ESRD) patients: 42 (70%) treated with HD and 18 patients (30%) with HDF. The median (interquartile range) age was 65.0 (55.0-74.5) years. All patients developed seroprotection to at least one influenza vaccine strain at one month post-vaccination, and did not differ between groups. By logistic regression, age was the only factor independently associated with seroconversion to all vaccine strains (odds ratio 0.89, 95% confidence interval 0.80-0.98; p = 0.022). Seroprotection to all vaccine strains was sustained for longer in patients treated with HDF, and the results remained the same after age adjustment. For cellular immune response, patients who seroconverted to all vaccine strains had higher CD38+ T cell subpopulations pre-vaccination. Patients treated by HDF had higher lymphocyte proliferation to circulating influenza A strains.

Conclusions: Seroconversion to all influenza vaccine strains was associated with age. Patients treated with HDF demonstrated seroprotection was sustained for longer compared to those treated by HD and greater lymphocyte proliferation to circulating influenza A strains. These encouraging results for HDF require confirmation in a larger dialysis population.

Trial Registration: ClinicalTrial.gov, NCT04122222.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0227719PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996846PMC
April 2020

Viral etiologies of influenza-like illness and severe acute respiratory infections in Thailand.

Influenza Other Respir Viruses 2018 07 8;12(4):482-489. Epub 2018 May 8.

Influenza Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.

Background: Information on the burden, characteristics and seasonality of non-influenza respiratory viruses is limited in tropical countries.

Objectives: Describe the epidemiology of selected non-influenza respiratory viruses in Thailand between June 2010 and May 2014 using a sentinel surveillance platform established for influenza.

Methods: Patients with influenza-like illness (ILI; history of fever or documented temperature ≥38°C, cough, not requiring hospitalization) or severe acute respiratory infection (SARI; history of fever or documented temperature ≥38°C, cough, onset <10 days, requiring hospitalization) were enrolled from 10 sites. Throat swabs were tested for influenza viruses, respiratory syncytial virus (RSV), metapneumovirus (MPV), parainfluenza viruses (PIV) 1-3, and adenoviruses by polymerase chain reaction (PCR) or real-time reverse transcriptase-PCR.

Results: We screened 15 369 persons with acute respiratory infections and enrolled 8106 cases of ILI (5069 cases <15 years old) and 1754 cases of SARI (1404 cases <15 years old). Among ILI cases <15 years old, influenza viruses (1173, 23%), RSV (447, 9%), and adenoviruses (430, 8%) were the most frequently identified respiratory viruses tested, while for SARI cases <15 years old, RSV (196, 14%) influenza (157, 11%) and adenoviruses (90, 6%) were the most common. The RSV season significantly overlapped the larger influenza season from July to November in Thailand.

Conclusions: The global expansion of influenza sentinel surveillance provides an opportunity to gather information on the characteristics of cases positive for non-influenza respiratory viruses, particularly seasonality, although adjustments to case definitions may be required.
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http://dx.doi.org/10.1111/irv.12554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005612PMC
July 2018

The acceptability and validity of self-collected nasal swabs for detection of influenza virus infection among older adults in Thailand.

Influenza Other Respir Viruses 2017 09 12;11(5):412-417. Epub 2017 Sep 12.

Influenza Program, Thailand Ministry of Public Health-U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.

Background: Self-collection of nasal swabs could improve the timeliness of influenza virus detection in older adults.

Objectives: Measure the acceptability, adequacy, timeliness, and validity of self-collected nasal swabs among adults >65 years in Thailand.

Methods: Our evaluation consisted of two parts: a one-month study among randomly selected, community-dwelling older adults to simulate community-based surveillance for acute respiratory infections (ARI); and a clinic study of older adults with ARI to evaluate the sensitivity and specificity of self-collected nasal swabs for influenza virus infection compared with healthcare worker (HCW)-collected nasal and nasopharyngeal swabs.

Results: In the community study, 24% of participants experienced an ARI during the observation period. All (100%) participants with an ARI self-collected nasal swabs within 72 hours of symptom onset of which 92% were considered adequate samples. In the clinic study, 45% of patients with ARI presented within 72 hours of symptom onset. The sensitivity of self-collected nasal swabs for detection of influenza virus infection was 78% (95% CI 40-97) compared to nasopharyngeal and 88% (95% CI 47-100) compared to nasal swabs collected by HCWs. Specificity was 100% (95% CI 97-100) compared to both methods. Self-collection of nasal swabs was found acceptable by 99% of participants in both studies.

Conclusions: Self-collection of nasal swabs was acceptable to older adults in Thailand who were able to take adequate samples. Self-collection of nasal swabs may improve the timeliness of sample collection but lower sensitivity will need to be considered.
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http://dx.doi.org/10.1111/irv.12471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5596524PMC
September 2017

Global Role and Burden of Influenza in Pediatric Respiratory Hospitalizations, 1982-2012: A Systematic Analysis.

PLoS Med 2016 Mar 24;13(3):e1001977. Epub 2016 Mar 24.

Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.

Background: The global burden of pediatric severe respiratory illness is substantial, and influenza viruses contribute to this burden. Systematic surveillance and testing for influenza among hospitalized children has expanded globally over the past decade. However, only a fraction of the data has been used to estimate influenza burden. In this analysis, we use surveillance data to provide an estimate of influenza-associated hospitalizations among children worldwide.

Methods And Findings: We aggregated data from a systematic review (n = 108) and surveillance platforms (n = 37) to calculate a pooled estimate of the proportion of samples collected from children hospitalized with respiratory illnesses and positive for influenza by age group (<6 mo, <1 y, <2 y, <5 y, 5-17 y, and <18 y). We applied this proportion to global estimates of acute lower respiratory infection hospitalizations among children aged <1 y and <5 y, to obtain the number and per capita rate of influenza-associated hospitalizations by geographic region and socio-economic status. Influenza was associated with 10% (95% CI 8%-11%) of respiratory hospitalizations in children <18 y worldwide, ranging from 5% (95% CI 3%-7%) among children <6 mo to 16% (95% CI 14%-20%) among children 5-17 y. On average, we estimated that influenza results in approximately 374,000 (95% CI 264,000 to 539,000) hospitalizations in children <1 y-of which 228,000 (95% CI 150,000 to 344,000) occur in children <6 mo-and 870,000 (95% CI 610,000 to 1,237,000) hospitalizations in children <5 y annually. Influenza-associated hospitalization rates were more than three times higher in developing countries than in industrialized countries (150/100,000 children/year versus 48/100,000). However, differences in hospitalization practices between settings are an important limitation in interpreting these findings.

Conclusions: Influenza is an important contributor to respiratory hospitalizations among young children worldwide. Increasing influenza vaccination coverage among young children and pregnant women could reduce this burden and protect infants <6 mo.
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http://dx.doi.org/10.1371/journal.pmed.1001977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807087PMC
March 2016

Assessment of potential public health impact of a quadrivalent inactivated influenza vaccine in Thailand.

Influenza Other Respir Viruses 2016 May 29;10(3):211-9. Epub 2016 Jan 29.

Influenza Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.

Background: Each year, an influenza B strain representing only one influenza B lineage is included in the trivalent inactivated influenza vaccine (IIV3); a mismatch between the selected lineage and circulating viruses can result in suboptimal vaccine effectiveness. We modeled the added potential public health impact of a quadrivalent inactivated influenza vaccine (IIV4) that includes strains from both influenza B lineages compared to IIV3 on influenza-associated morbidity and mortality in Thailand.

Methods: Using data on the incidence of influenza-associated hospitalizations and deaths, vaccine effectiveness, and vaccine coverage from the 2007-2012 influenza seasons in Thailand, we estimated rates of influenza-associated outcomes that might be averted using IIV4 instead of IIV3. We then applied these rates to national population estimates to calculate averted illnesses, hospitalizations, and deaths for each season. We assumed that the influenza B lineage included in IIV3 would provide a relative vaccine effectiveness of 75% against the other B lineage.

Results: Compared to use of IIV3, use of IIV4 might have led to an additional reduction ranging from 0·4 to 14·3 influenza-associated illnesses per 100 000 population/year, <0·1 to 0·5 hospitalizations per 100 000/year, and <0·1 to 0·4 deaths per 1000/year. Based on extrapolation to national population estimates, replacement of IIV3 with IIV4 might have averted an additional 267-9784 influenza-associated illnesses, 9-320 hospitalizations, and 0-3 deaths.

Conclusion: Compared to use of IIV3, IIV4 has the potential to further reduce the burden of influenza-associated morbidity and mortality in Thailand.
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http://dx.doi.org/10.1111/irv.12361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814859PMC
May 2016

The validity of clinical practice guidelines for empirical use of oseltamivir for influenza in Thai children.

Paediatr Int Child Health 2016 Nov;36(4):275-281

d Laboratory Section, Bamrasnaradura Infectious Diseases Institute, Ministry of Public Health (MOPH) , Nonthaburi , Thailand.

Background: Clinical practice guidelines for influenza have been implemented to maximise the appropriate use of empirical oseltamivir; however, good predictive values are required.

Methods: Between October 2011 and September 2013, children aged < 15 years who presented at the Bamrasnaradura Infectious Diseases Institute with an influenza-like illness plus either (i) pneumonia or (ii) being in a higher risk group for influenza complications were prospectively enrolled. Respiratory specimens were taken for real-time polymerase chain reaction testing (RT-PCR). Clinical characteristics, laboratory data and oseltamivir therapy were recorded.

Results: 85 cases were enrolled. Of these, the proportions of those with pneumonia, who were aged < 2 years and who had underlying diseases were 74.1%, 56.5% and 38.8%, respectively. RT-PCR detected respiratory syncytial virusamong (35.3%), influenza (22.3by%), adenovirus (14.1%), human metapneumovirus (5.9%), para-influenza (3.5%) and no viruses (25.9 %). Pneumonia (OR 0.16, 95% CI 0.05-0.50) and having two clinical criteria (OR 0.24, 95% CI 0.08-0.76) were significantly negative predictors of influenza. Having cluster transmissions (OR 5.18, 95% CI 1.38-19.37) and a monocyte proportion >7% (OR 3.58, 95% CI 1.15-11.17) were significantly positive predictors of influenza. The mean (SD) percentage of influenza-like illness during the study period was 7.04 (2.02).

Conclusions: Clinical criteria guidelines yielded a low predictive value (22.3%) for influenza in children. Seasonality, cluster transmission, white blood cell and differential counts may be helpful in diagnosing influenza. Nonetheless, empirical oseltamivir should not be delayed for those in need.
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http://dx.doi.org/10.1179/2046905515Y.0000000052DOI Listing
November 2016

Influenza-associated mortality in Thailand, 2006-2011.

Influenza Other Respir Viruses 2015 Nov;9(6):298-304

Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA.

Background: Influenza-associated mortality in subtropical or tropical regions, particularly in developing countries, remains poorly quantified and often underestimated. We analyzed data in Thailand, a middle-income tropical country with good vital statistics and influenza surveillance data.

Methods: We obtained weekly mortality data for all-cause and three underlying causes of death (circulatory and respiratory diseases, and pneumonia and influenza), and weekly influenza virus data, from 2006 to 2011. A negative binomial regression model was used to estimate deaths attributable to influenza in two age groups (<65 and ≥65 years) by incorporating influenza viral data as covariates in the model.

Results: From 2006 to 2011, the average annual influenza-associated mortality per 100 000 persons was 4·0 (95% CI: -18 to 26). Eighty-three percent of influenza-associated deaths occurred among persons aged > 65 years. The average annual rate of influenza-associated deaths was 0·7 (95% CI: -8·2 to 10) per 100 000 population for person aged <65 years and 42 (95% CI: -137 to 216) for person aged ≥ 65 years.

Discussion: In Thailand, estimated excess mortality associated with influenza was considerable even during non-pandemic years. These data provide support for Thailand's seasonal influenza vaccination campaign. Continued monitoring of mortality data is important to assess impact.
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http://dx.doi.org/10.1111/irv.12344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605410PMC
November 2015

Mortality attributable to seasonal influenza A and B infections in Thailand, 2005-2009: a longitudinal study.

Am J Epidemiol 2015 Jun 20;181(11):898-907. Epub 2015 Apr 20.

Influenza epidemiology differs substantially in tropical and temperate zones, but estimates of seasonal influenza mortality in developing countries in the tropics are lacking. We aimed to quantify mortality due to seasonal influenza in Thailand, a tropical middle-income country. Time series of polymerase chain reaction-confirmed influenza infections between 2005 and 2009 were constructed from a sentinel surveillance network. These were combined with influenza-like illness data to derive measures of influenza activity and relationships to mortality by using a Bayesian regression framework. We estimated 6.1 (95% credible interval: 0.5, 12.4) annual deaths per 100,000 population attributable to influenza A and B, predominantly in those aged ≥60 years, with the largest contribution from influenza A(H1N1) in 3 out of 4 years. For A(H3N2), the relationship between influenza activity and mortality varied over time. Influenza was associated with increases in deaths classified as resulting from respiratory disease (posterior probability of positive association, 99.8%), cancer (98.6%), renal disease (98.0%), and liver disease (99.2%). No association with circulatory disease mortality was found. Seasonal influenza infections are associated with substantial mortality in Thailand, but evidence for the strong relationship between influenza activity and circulatory disease mortality reported in temperate countries is lacking.
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http://dx.doi.org/10.1093/aje/kwu360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4445392PMC
June 2015

Detecting Spread of Avian Influenza A(H7N9) Virus Beyond China.

Emerg Infect Dis 2015 May;21(5):741-9

During February 2013-March 2015, a total of 602 human cases of low pathogenic avian influenza A(H7N9) were reported; no autochthonous cases were reported outside mainland China. In contrast, since highly pathogenic avian influenza A(H5N1) reemerged during 2003 in China, 784 human cases in 16 countries and poultry outbreaks in 53 countries have been reported. Whether the absence of reported A(H7N9) outside mainland China represents lack of spread or lack of detection remains unclear. We compared epidemiologic and virologic features of A(H5N1) and A(H7N9) and used human and animal influenza surveillance data collected during April 2013-May 2014 from 4 Southeast Asia countries to assess the likelihood that A(H7N9) would have gone undetected during 2014. Surveillance in Vietnam and Cambodia detected human A(H5N1) cases; no A(H7N9) cases were detected in humans or poultry in Southeast Asia. Although we cannot rule out the possible spread of A(H7N9), substantial spread causing severe disease in humans is unlikely.
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http://dx.doi.org/10.3201/eid2105.141756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4412232PMC
May 2015

Risk factors and outcomes of influenza infection among children presenting with influenza-like illness.

J Med Assoc Thai 2014 Jun;97 Suppl 6:S40-6

Objective: Limited data were available to guide management, counseling, and/or diagnostic investigation among children presenting with influenza-like illness (ILI). During a recent period of high influenza activity, we wished to determine the frequency, outcomes, and factors associated with influenza infection among children presenting with ILI.

Material And Method: During September and October 2010, children presenting with ILI were enrolled. Nasal swabs were sent for polymerase chain reaction (PCR) to determine the frequency and types of influenza. Information of demographic characteristics, potential risk factors, and short-term outcomes of study participants were collected.

Results: Among 300 enrolled subjects, influenza infections were identified in 170 (56.7%) cases; 45.7% (n = 137) were influenza A and 11% (n = 33) were influenza B. Most cases recovered uneventfully with a 3.7% (n = 11) hospitalization rate. Risks for hospitalization did not differ by infection status (2.4% vs. 5.4% between those with and without influenza infection, respectively) or types of influenza infection. Logistic regression analysis indicated that older age, having a household member with acute respiratory illness (ARI) during the previous 7 days, having an underlying co-morbidity, and a history of premature birth were associated with influenza, with adjusted odds ratios and 95% confidence intervals of 1.19 (1.087, 1.30), 3.21 (1.096, 9.424), 2.15 (1.244, 3.728), and 0.08 (0.007, 0.876), respectively.

Conclusion: The outcomes of influenza-associated ILI were generally favourable, with no fatalities and 2.4% risk for hospitalization. Among children presenting with ILI, age, household contact with ARI, and co morbidities increased the likelihood of influenza, whereas history of premature birth was negatively associated with influenza.
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June 2014

A human monoclonal antibody derived from a vaccinated volunteer recognizes heterosubtypically a novel epitope on the hemagglutinin globular head of H1 and H9 influenza A viruses.

Biochem Biophys Res Commun 2014 Sep 6;452(3):865-70. Epub 2014 Sep 6.

Department of Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Japan Science and Technology Agency/Japan International Cooperation Agency, Science and Technology Research Partnership for Sustainable Development (JST/JICA, SATREPS), Tokyo, Japan. Electronic address:

Most neutralizing antibodies elicited during influenza virus infection or by vaccination have a narrow spectrum because they usually target variable epitopes in the globular head region of hemagglutinin (HA). In this study, we describe a human monoclonal antibody (HuMAb), 5D7, that was prepared from the peripheral blood lymphocytes of a vaccinated volunteer using the fusion method. The HuMAb heterosubtypically neutralizes group 1 influenza A viruses, including seasonal H1N1, 2009 pandemic H1N1 (H1N1pdm) and avian H9N2, with a strong hemagglutinin inhibition activity. Selection of an escape mutant showed that the HuMAb targets a novel conformational epitope that is located in the HA head region but is distinct from the receptor binding site. Furthermore, Phe114Ile substitution in the epitope made the HA unrecognizable by the HuMAb. Amino acid residues in the predicted epitope region are also highly conserved in the HAs of H1N1 and H9N2. The HuMAb reported here may be a potential candidate for the development of therapeutic/prophylactic antibodies against H1 and H9 influenza viruses.
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http://dx.doi.org/10.1016/j.bbrc.2014.09.008DOI Listing
September 2014

High rate of A(H1N1)pdm09 infections among rural Thai villagers, 2009-2010.

PLoS One 2014 4;9(9):e106751. Epub 2014 Sep 4.

College of Public Health and Health Professions and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.

Background: Pandemic influenza A(H1N1)pdm09 emerged in Thailand in 2009. A prospective longitudinal adult cohort and household transmission study of influenza-like illness (ILI) was ongoing in rural Thailand at the time of emergence. Symptomatic and subclinical A(H1N1)pdm09 infection rates in the cohort and among household members were evaluated.

Methods: A cohort of 800 Thai adults underwent active community-based surveillance for ILI from 2008-2010. Acute respiratory samples from ILI episodes were tested for A(H1N1)pdm09 by qRT-PCR; acute and 60-day convalescent blood samples were tested by A(H1N1)pdm09 hemagglutination inhibition assay (HI). Enrollment, 12-month and 24-month follow-up blood samples were tested for A(H1N1)pdm09 seroconversion by HI. Household members of influenza A-infected cohort subjects with ILI were enrolled in household transmission investigations in which day 0 and 60 blood samples and acute respiratory samples were tested by either qRT-PCR or HI for A(H1N1)pdm09. Seroconversion between annual blood samples without A(H1N1)pdm09-positive ILI was considered as subclinical infection.

Results: The 2-yr cumulative incidence of A(H1N1)pdm09 infection in the cohort in 2009/2010 was 10.8% (84/781) with an annual incidence of 1.2% in 2009 and 9.7% in 2010; 83.3% of infections were subclinical (50% in 2009 and 85.9% in 2010). The 2-yr cumulative incidence was lowest (5%) in adults born ≤ 1957. The A(H1N1)pdm09 secondary attack rate among household contacts was 47.2% (17/36); 47.1% of these infections were subclinical. The highest A(H1N1)pdm09 secondary attack rate among household contacts (70.6%, 12/17) occurred among children born between 1990 and 2003.

Conclusion: Subclinical A(H1N1)pdm09 infections in Thai adults occurred frequently and accounted for a greater proportion of all A(H1N1)pdm09 infections than previously estimated. The role of subclinical infections in A(H1N1)pdm09 transmission has important implications in formulating strategies to predict and prevent the spread of A(H1N1)pdm09 and other influenza virus strains.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106751PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4154756PMC
December 2015

Influenza seasonality and vaccination timing in tropical and subtropical areas of southern and south-eastern Asia.

Bull World Health Organ 2014 May 24;92(5):318-30. Epub 2014 Feb 24.

International Centre for Diarrhoeal Disease Research Bangladesh, Dhaka, Bangladesh .

Objective: To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator.

Methods: Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries.

Findings: Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator.

Conclusion: Most southern and south-eastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.
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http://dx.doi.org/10.2471/BLT.13.124412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4007122PMC
May 2014

Effectiveness of the 2010 and 2011 Southern Hemisphere trivalent inactivated influenza vaccines against hospitalization with influenza-associated acute respiratory infection among Thai adults aged ≥ 50 years.

Influenza Other Respir Viruses 2014 Jul 3;8(4):463-8. Epub 2014 Feb 3.

Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA.

Background: Inactivated influenza vaccine (IIV) effectiveness has been evaluated among older adults in high-income countries, but data on IIV effectiveness in low- and middle-income countries remain sparse. We conducted a test-negative case-control analysis to estimate 2010 and 2011 trivalent IIV effectiveness against hospitalization with influenza-associated acute respiratory infection (ARI) among persons aged ≥ 50 years in rural Thailand.

Methods: During 2010-2011, active surveillance for ARI hospitalization was conducted in two provinces; patients were tested for influenza viruses by real-time RT-PCR. Vaccination status was obtained from vaccine registries. Case and control patients were patients with nasopharyngeal swabs positive and negative for influenza viruses, respectively. Vaccine effectiveness (VE) was estimated for the 6 months after vaccination began. Logistic regression was used to evaluate the association between case status and vaccination while adjusting for age, province, medical conditions, and time.

Results: During 2010-2011, there were 1545 patients with ARI, of whom 279 (18%) were influenza-positive case patients and 1266 (82%) were influenza-negative control patients. Of the 279 case patients, 247 (89%) had influenza A and 32 (11%) had influenza B. Fourteen of 279 (5%) case patients and 108 of 1266 (9%) control patients were vaccinated against influenza. The unadjusted IIV effectiveness against hospitalization with influenza-associated ARI was 43% (95% CI: 0-68%); adjusted VE was 47% (95% CI: 5-71%).

Conclusion: The 2010 and 2011 IIVs were moderately effective against hospitalization with influenza-associated ARI among Thais aged ≥ 50 years, but IIV coverage was low. Additional efforts are warranted in Thailand to improve IIV uptake in this target group.
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http://dx.doi.org/10.1111/irv.12233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4181806PMC
July 2014

Respiratory syncytial virus circulation in seven countries with Global Disease Detection Regional Centers.

J Infect Dis 2013 Dec;208 Suppl 3:S246-54

Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases.

Background: Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in young children globally, with the highest burden in low- and middle-income countries where the association between RSV activity and climate remains unclear.

Methods: Monthly laboratory-confirmed RSV cases and associations with climate data were assessed for respiratory surveillance sites in tropical and subtropical areas (Bangladesh, China, Egypt, Guatemala, Kenya, South Africa, and Thailand) during 2004-2012. Average monthly minimum and maximum temperatures, relative humidity, and precipitation were calculated using daily local weather data from the US National Climatic Data Center.

Results: RSV circulated with 1-2 epidemic periods each year in site areas. RSV seasonal timing and duration were generally consistent within country from year to year. Associations between RSV and weather varied across years and geographic locations. RSV usually peaked in climates with high annual precipitation (Bangladesh, Guatemala, and Thailand) during wet months, whereas RSV peaked during cooler months in moderately hot (China) and arid (Egypt) regions. In South Africa, RSV peaked in autumn, whereas no associations with seasonal weather trends were observed in Kenya.

Conclusions: Further understanding of RSV seasonality in developing countries and various climate regions will be important to better understand the epidemiology of RSV and for timing the use of future RSV vaccines and immunoprophylaxis in low- and middle-income countries.
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http://dx.doi.org/10.1093/infdis/jit515DOI Listing
December 2013

Hospitalizations for acute lower respiratory tract infection due to respiratory syncytial virus in Thailand, 2008-2011.

J Infect Dis 2013 Dec;208 Suppl 3:S238-45

International Emerging Infections Program, Global Disease Detection Regional Center, Thailand Ministry of Public Health (MOPH)-US Centers for Disease Control and Prevention Collaboration.

Background: Few population-based estimates of the incidence of respiratory syncytial virus (RSV) infection in low- or middle-income countries are available. We describe the incidence and epidemiology of hospitalizations for RSV-associated acute lower respiratory tract infection (ALRI) detected by active population-based surveillance in 2 rural Thailand provinces during 2008-2011.

Methods: Patients hospitalized with ALRI were systematically sampled. Consenting patients provided nasopharyngeal swab specimens for RSV testing by real-time reverse-transcription polymerase chain reaction.

Results: Of 13 982 enrolled patients hospitalized with ALRI, 1137 (8.1%) were RSV positive. After adjustment for sampling and nonenrollment, the incidence of RSV-associated ALRI hospitalization was 85 cases per 100,000 persons/year. The highest rates occurred among children aged <5 years (981 cases per 100,000 persons/year) and <1 year (1543 cases per 100,000 persons/year). Rates were low among older children and young adults but high among persons aged >65 years (130 cases per 100,000 persons/year). Eight (0.7%) RSV-infected study patients died during hospitalization. Annual RSV hospitalizations peaked during July-October with almost no documented RSV hospitalizations during January-June.

Conclusions: Our findings demonstrate the substantial contribution of RSV to global ALRI burden, especially in children aged <5 years and the elderly, and underscore the urgent need for effective prevention measures.
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http://dx.doi.org/10.1093/infdis/jit456DOI Listing
December 2013

Incidence and etiology of acute lower respiratory tract infections in hospitalized children younger than 5 years in rural Thailand.

Pediatr Infect Dis J 2014 Feb;33(2):e45-52

From the *CDC-Hubert Global Health Fellow, Centers for Disease Control and Prevention, Atlanta, GA; †International Emerging Infections Program, Global Disease Detection Regional Center, Thailand Ministry of Public Health-US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand; ‡Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA; §National Institute of Health, Thailand Ministry of Public Health, Nonthaburi, Thailand; ¶Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA; ‖Nakhon Phanom Provincial Hospital, Nakhon Phanom; **Crown Prince Hospital, Sa Kaeo, Thailand; and ††Division of Global Disease Detection and Emergency Response, Centers for Disease Control and Prevention, Atlanta, GA.

Background: Pneumonia remains a leading cause of under-five morbidity and mortality globally. Comprehensive incidence, epidemiologic and etiologic data are needed to update prevention and control strategies.

Methods: We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory tract infections (ALRI) among children <5 years of age in rural Thailand. ALRI cases were systematically sampled for an etiology study that tested nasopharyngeal specimens by polymerase chain reaction; children without ALRI were enrolled as controls from outpatient clinics.

Results: We identified 28,543 hospitalized ALRI cases from 2005 to 2010. Among the 49% with chest radiographs, 76% had findings consistent with pneumonia as identified by 2 study radiologists. The hospitalized ALRI incidence rate was 5772 per 100,000 child-years (95% confidence interval: 5707, 5837) and was higher in boys versus girls (incidence rate ratio 1.38, 95% confidence interval: 1.35-1.41) and in children 6-23 months of age versus other age groups (incidence rate ratio 1.76, 95% confidence interval: 1.69-1.84). Viruses most commonly detected in ALRI cases were respiratory syncytial virus (19.5%), rhinoviruses (18.7%), bocavirus (12.8%) and influenza viruses (8%). Compared with controls, ALRI cases were more likely to test positive for respiratory syncytial virus, influenza, adenovirus, human metapneumovirus and parainfluenza viruses 1 and 3 (P ≤ 0.01 for all). Bloodstream infections, most commonly Streptococcus pneumoniae and nontyphoidal Salmonella, accounted for 1.8% of cases.

Conclusions: Our findings underscore the high burden of hospitalization for ALRI and the importance of viral pathogens among children in Thailand. Interventions targeting viral pathogens coupled with improved diagnostic approaches, especially for bacteria, are critical for better understanding of ALRI etiology, prevention and control.
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http://dx.doi.org/10.1097/INF.0000000000000062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667718PMC
February 2014

Efficacy of the trivalent influenza vaccination in Thai patients with hemodialysis or kidney transplant compared with healthy volunteers.

J Med Assoc Thai 2013 Mar;96 Suppl 3:S1-7

Department of Medicine, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand.

Objective: To evaluate the immune response to trivalent influenza vaccination in Thai patients with hemodialysis (HD) or kidney transplant (KT) compared with healthy volunteers.

Material And Method: This was a cross-sectional study in Thai healthy volunteers and patients with HD and KT who received the trivalent influenza vaccine provided by the Ministry of Public Health of Thailand from 1 November 2011 to 31 December 2011. Each subject was injected intramuscularly with one dose (0.5 milliliter) of trivalent influenza vaccine containing viral strains recommended by the WHO for the 2011 influenza season (southern hemisphere). Blood samples before and 6 weeks after the vaccination were measured for immune response using a hemagglutination-inhibition antibody assay.

Results: Subjects consisted of 30 healthy volunteers, 30 patients with HD and 30 patients with KT Prevalence of pre-vaccination seroprotective (SP) immunity in each group (healthy volunteers, HD, KT) was as follows: against H1N1 (33.3%: 23.3%: 10.0%), H3N2 (80.0%: 26.7%: 23.3%) and B (60.0%: 20.0%: 3.30%) viral strains, respectively. Those who were seronegative (SN) before testing positive after one dose of this vaccine were as follows: H1N1 (100.0%: 73.9%: 74.1%), H3N2 (66.7%: 86.4%: 34.8%) or B (58.3%: 66. 7%: 48.3%) viral strains, respectively. The healthy group showed significantly higher SP immune response for H1N1 than the HD and KT groups (p = 0.023). The HD group had significantly higher SP immune response for H3N2 than the KT groups (p = 0.001). Immune responses for the B vaccine in all groups were not different. No major adverse event was found in any group.

Conclusion: Immune response for H1N1 vaccine in the HD and KT groups was slightly less than that of the healthy group. Immune response for H3N2 vaccine in the KT groups was less than in the healthy and HD groups. Immune responses for B vaccine in all groups were not different.
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March 2013

Influenza antiviral resistance in the Asia-Pacific region during 2011.

Antiviral Res 2013 Feb 25;97(2):206-10. Epub 2012 Dec 25.

WHO Collaborating Centre for Reference and Research on Influenza, North Melbourne, Victoria, Australia.

Despite greater than 99% of influenza A viruses circulating in the Asia-Pacific region being resistant to the adamantane antiviral drugs in 2011, the large majority of influenza A (>97%) and B strains (∼99%) remained susceptible to the neuraminidase inhibitors oseltamivir and zanamivir. However, compared to the first year of the 2009 pandemic, cases of oseltamivir-resistant A(H1N1)pdm09 viruses with the H275Y neuraminidase mutation increased in 2011, primarily due to an outbreak of oseltamivir-resistant viruses that occurred in Newcastle, as reported in Hurt et al. (2011c, 2012a), where the majority of the resistant viruses were from community patients not being treated with oseltamivir. A small number of influenza B viruses with reduced oseltamivir or zanamivir susceptibility were also detected. The increased detection of neuraminidase inhibitor resistant strains circulating in the community and the detection of novel variants with reduced susceptibility are reminders that monitoring of influenza viruses is important to ensure that antiviral treatment guidelines remain appropriate.
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http://dx.doi.org/10.1016/j.antiviral.2012.12.016DOI Listing
February 2013

Incidence and epidemiology of hospitalized influenza cases in rural Thailand during the influenza A (H1N1)pdm09 pandemic, 2009-2010.

PLoS One 2012 6;7(11):e48609. Epub 2012 Nov 6.

International Emerging Infections Program, Thailand Ministry of Public Health (MOPH) - U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.

Background: Data on the burden of the 2009 influenza pandemic in Asia are limited. Influenza A(H1N1)pdm09 was first reported in Thailand in May 2009. We assessed incidence and epidemiology of influenza-associated hospitalizations during 2009-2010.

Methods: We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infection (ALRI) in all 20 hospitals in two rural provinces. ALRI patients were sampled 1∶2 for participation in an etiology study in which nasopharyngeal swabs were collected for influenza virus testing by PCR.

Results: Of 7,207 patients tested, 902 (12.5%) were influenza-positive, including 190 (7.8%) of 2,436 children aged <5 years; 86% were influenza A virus (46% A(H1N1)pdm09, 30% H3N2, 6.5% H1N1, 3.5% not subtyped) and 13% were influenza B virus. Cases of influenza A(H1N1)pdm09 first peaked in August 2009 when 17% of tested patients were positive. Subsequent peaks during 2009 and 2010 represented a mix of influenza A(H1N1)pdm09, H3N2, and influenza B viruses. The estimated annual incidence of hospitalized influenza cases was 136 per 100,000, highest in ages <5 years (477 per 100,000) and >75 years (407 per 100,000). The incidence of influenza A(H1N1)pdm09 was 62 per 100,000 (214 per 100,000 in children <5 years). Eleven influenza-infected patients required mechanical ventilation, and four patients died, all adults with influenza A(H1N1)pdm09 (1) or H3N2 (3).

Conclusions: Influenza-associated hospitalization rates in Thailand during 2009-10 were substantial and exceeded rates described in western countries. Influenza A(H1N1)pdm09 predominated, but H3N2 also caused notable morbidity. Expanded influenza vaccination coverage could have considerable public health impact, especially in young children.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048609PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3490866PMC
April 2013

Neutralization titers against influenza A (H3N2) and influenza B viruses among a non-vaccinated population from Thailand.

Southeast Asian J Trop Med Public Health 2012 May;43(3):674-9

Medical Biotechnology Center, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand.

Influenza A and B viruses are viral respiratory pathogens that can cause severe infections among birds and mammals. Neutralization assays using human sera are useful to evaluate the risk of circulating viruses to humans. In this study, 359 serum samples from healthy Thai volunteers, who had not been vaccinated against influenza for at least five years, were investigated by microneutralization (MN) assays against influenza A H3N2 and influenza B viruses in 2009. There was no significant difference in neutralization activities against 2006 and 2008 isolates of influenza A H3N2 viruses. However, neutralization titers to influenza B viruses among 2008 isolates were quite low. The results indicate the non-vaccinated study population had some neutralizing antibodies against influenza A H3N2 but not against influenza B viruses.
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May 2012

Concurrent influenza virus infection and tuberculosis in patients hospitalized with respiratory illness in Thailand.

Influenza Other Respir Viruses 2013 May 21;7(3):244-8. Epub 2012 Jul 21.

Thailand MOPH-U.S. CDC Collaboration, Nonthaburi, Thailand.

Thailand, where influenza viruses circulate year-round, is one of 22 WHO-designated high-burden countries for tuberculosis (TB). Surveillance for hospitalized respiratory illness between 2003 and 2011 revealed 23 (<1% of 7180 tested) with concurrent influenza and TB. Only two persons were previously known to have TB suggesting that acute respiratory illness may bring patients to medical attention and lead to TB diagnosis. Influenza/TB was not associated with higher disease severity or mortality.
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http://dx.doi.org/10.1111/j.1750-2659.2012.00413.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779833PMC
May 2013