Publications by authors named "Melanie de Boer"

7 Publications

  • Page 1 of 1

Incidence of dengue illness in Mexican people aged 6 months to 50 years old: A prospective cohort study conducted in Jalisco.

PLoS One 2021 5;16(5):e0250253. Epub 2021 May 5.

Vaccines, GSK, Rockville, Maryland, United States of America.

Background And Objectives: The burden of dengue virus (DENV), a mosquito-borne pathogen, remains difficult to assess due to misdiagnosis and underreporting. Moreover, the large proportion of asymptomatic dengue cases impairs comprehensive assessment of its epidemiology even where effective surveillance systems are in place. We conducted a prospective community-based study to assess the incidence of symptomatic dengue cases in Zapopan and neighboring municipalities in the state of Jalisco, Mexico.

Methods: Healthy subjects aged 6 months to 50 years living in households located in the Zapopan and neighboring municipalities were enrolled for a 24-month follow-up study (NCT02766088). Serostatus was determined at enrolment and weekly contacts were conducted via phone calls and home visits. Participants had to report any febrile episode lasting for at least two days. Suspected dengue cases were tested by reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR), detection of non-structural protein 1 (NS1), anti-DENV immunoglobulin G and M (IgG and IgM) assays.

Results: A total of 350 individuals from 87 households were enrolled. The overall seroprevalence of anti-DENV IgG at enrolment was 19.4% (95% confidence interval [CI] 14.5-25.6) with the highest seroprevalence rate observed in the adult group. Over the 27-month study period from July 2016 to September 2018, a total of 18 suspected dengue cases were reported. Four cases were confirmed by RT-qPCR and serotyped as DENV-1. A fifth case was confirmed by the NS1 assay. The 13 remaining suspected cases were tested negative by these assays. Based on the 5 virologically confirmed cases, symptomatic dengue incidence proportion of 1.4% (95%CI 0.5-3.8) was estimated. No severe cases or hospitalizations occurred during the study.

Conclusion: Community-based active surveillance was shown as efficient to detect symptomatic dengue cases.

Clinical Trial Registration: NCT02766088.
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May 2021

A prospective, multicentre, cohort study to assess the incidence of dengue illness in households from selected communities in Brazil (2014-2018).

Int J Infect Dis 2021 Apr 21. Epub 2021 Apr 21.

Instituto de Tecnologia em Imunobiológicos Bio-Manguinhos/Fiocruz, Avenida Brasil 4.365, Manguinhos, Rio de Janeiro - RJ, 21.040-900, Brazil.

Objectives: To estimate the incidence of dengue infection across geographically distinct areas of Brazil.

Methods: This prospective, household-based, cohort study enrolled participants in five areas and followed them up for up to 4 years (2014-2018). Dengue seroprevalence was assessed at each scheduled visit. Suspected dengue cases were identified through enhanced passive and active surveillance. Acute symptomatic dengue infection was confirmed through reverse-transcriptase quantitative polymerase chain reaction in combination with an antigenic assay (NS1) and serology.

Results: Among 3300 participants enrolled, baseline seroprevalence was 76.2%, although only 23.3% of participants reported a history of dengue. Of 1284 suspected symptomatic dengue cases detected, 50 (3.9%) were laboratory-confirmed. Based on 8166.5 person-years (PY) of follow-up, the incidence of laboratory-confirmed symptomatic infection (primary endpoint) was 6.1 per 1000 PY (95% confidence interval [CI]: 4.5, 8.1). Incidence varied substantially in different years (1.8-7.4 per 1000 PY). The incidence of inapparent primary dengue infection was substantially higher: 41.7 per 1000 PY (95% CI: 31.1, 54.6).

Conclusions: Our findings, highlighting that the incidence of dengue infection is underestimated in Brazil, will inform the design and implementation of future dengue vaccine trials.

Clinical Trial Registration: NCT01751139.
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April 2021

An epidemiological study to assess Plasmodium falciparum parasite prevalence and malaria control measures in Burkina Faso and Senegal.

Malar J 2017 02 6;16(1):63. Epub 2017 Feb 6.

GSK Vaccines, Wavre, Belgium.

Background: Malariometric information is needed to decide how to introduce malaria vaccines and evaluate their impact in sub-Saharan African countries.

Methods: This cross-sectional study (NCT01954264) was conducted between October and November, 2013, corresponding to the high malaria transmission season, in four sites with Health and Demographic Surveillance Systems (DSS) [two sites with moderate-to-high malaria endemicity in Burkina Faso (Nouna and Saponé) and two sites with low malaria endemicity in Senegal (Keur Socé and Niakhar)]. Children (N = 2421) were randomly selected from the DSS lists of the study sites and were stratified into two age groups (6 months-4 years and 5-9 years). A blood sample was collected from each child to evaluate parasite prevalence of Plasmodium falciparum and other Plasmodium species and gametocyte density by microscopy, and rapid diagnosis test in the event of fever within 24 h. Case report forms were used to evaluate malaria control measures and other factors.

Results: Plasmodium falciparum was identified in 707 (29.2%) children, with a higher prevalence in Burkina Faso than Senegal (57.5 vs 0.9% of children). In Burkina Faso, prevalence was 57.7% in Nouna and 41.9% in Saponé in the 6 months-4 years age group, and 75.4% in Nouna and 70.1% in Saponé in the 5-9 years age group. Infections with other Plasmodium species were rare and only detected in Burkina Faso. While mosquito nets were used by 88.6-97.0 and 64.7-80.2% of children in Burkina Faso and Senegal, other malaria control measures evaluated at individual level were uncommon. In Burkina Faso, exploratory analyses suggested that use of malaria treatment or any other medication within 14 days, and use of insecticide spray within 7 days decreased the prevalence of malaria infection; older age, rural residence, natural floor, grass/palm roof, and unavailability of electricity in the house were factors associated with increased malaria occurrence.

Conclusions: Plasmodium falciparum infection prevalence in children younger than 10 years was 57.5% in Burkina Faso and 0.9% in Senegal, and variability was observed, among others, by age, study site and malaria control measures.
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February 2017

Using collaborative learning to improve diabetes care and outcomes: the VIDA project.

Prim Care Diabetes 2010 Oct 15;4(3):145-53. Epub 2010 May 15.

Pan American Health Organization, Washington, DC 20037-2895, USA.

Unlabelled: The prevalence of diabetes in Mexico among those 20-64 years of age has increased from 7.2% in 1993 to 10.7% in 2000. National population-based surveys in Mexico demonstrated that 50% of the total population with diabetes had blood glucose levels of 200mg/dl or higher. Thus, diabetes care has become one of the most important public health challenges in this country. The aim of the study was to improve the quality of diabetes care in primary health care centers using the chronic care model and the breakthrough series (BTS) collaborative methodology.

Methods: Ten public health centers in the cities of Xalapa and Veracruz were randomly selected to participate in the project. Five of the health centers were randomly assigned to receive the intervention (intervention group) and the other five followed usual care (usual care group). The intervention was evaluated by A1c test before and after the intervention in both groups of patients. Patients were followed for 18 months from November 2002 to May 2004. Results were adjusted for the clustering of patients within practices and baseline measure.

Results: The proportion of people with good glycemic control (A1c<7%) among those in the intervention group increased from 28% before the intervention to 39% after the intervention. The proportion of patients achieving three or more quality improvement goals increased from 16.6% to 69.7% (p<0.001) among the intervention group while the usual care group experienced a non-significant decrease from 12.4% to 5.9% (p=0.118). The focus on the primary care team and the participation of people with diabetes were strategic elements incorporated into the methodology, expected to ensure sustainability of continued improvement of health outcomes.

Conclusions: The intervention introduced modifications to solve problems identified by health teams in their practice and improved process and outcome measures of quality diabetes care. Most of the actions were directed at four components of the chronic care model: self-management support, decision support, delivery system design, and clinical information systems.
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October 2010

Effect of transport interval on out-of-hospital cardiac arrest survival in the OPALS study: implications for triaging patients to specialized cardiac arrest centers.

Ann Emerg Med 2009 Aug 23;54(2):248-55. Epub 2009 Jan 23.

Arizona Emergency Medicine Research Center, Department of Emergency Medicine, College of Medicine, The University of Arizona, Tucson, AZ.

Study Objective: To identify any association between out-of-hospital transport interval and survival to hospital discharge in victims of out-of-hospital cardiac arrest.

Methods: Data from the Ontario Prehospital Advanced Life Support Study (January 1, 1991, to December 31, 2002), an Utstein-compliant registry of out-of-hospital cardiac arrest patients from 21 communities, were analyzed. Logistic regression identified factors that were independently associated with survival in consecutive adult, nontraumatic, out-of-hospital cardiac arrest patients and in the subgroup with return of spontaneous circulation.

Results: A total of 18,987 patients met criteria and 15,559 (81.9%) had complete data for analysis (study group). Return of spontaneous circulation was achieved in 2,299 patients (14.8%), and 689 (4.4%) survived to hospital discharge. Median transport interval was 4.0 minutes (25th quartile 3.0 minutes; 75th quartile 6.2 minutes) for survivors and 4.2 minutes (25th quartile 3.0, 75th quartile 6.2) for nonsurvivors. Logistic regression revealed multiple factors that were independently associated with survival: witnessed arrest (odds ratio 2.61; 95% confidence interval [CI] 2.05 to 3.34), bystander cardiopulmonary resuscitation (odds ratio 2.22; 95% CI 1.82 to 2.70), initial rhythm of ventricular fibrillation/tachycardia (odds ratio 2.22; 95% CI 1.97 to 2.50), and shorter emergency medical services (EMS) response interval (odds ratio 1.26; 95% CI 1.20 to 1.33). There was no association between transport interval and survival in either the study group (odds ratio 1.01; 95% CI 0.99 to 1.05) or the return of spontaneous circulation subgroup (odds ratio 1.04; 95% CI 0.99, 1.08).

Conclusion: In a large out-of-hospital cardiac arrest study from demographically diverse EMS systems, longer transport interval was not associated with decreased survival. Given the growing evidence showing major influence from specialized postarrest care, these findings support conducting clinical trials that assess the effectiveness and safety of bypassing local hospitals to take patients to regional cardiac arrest centers.
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August 2009

Hazmat disaster preparedness in Hong Kong: what are the hazardous materials on Lantau, Lamma, and Hong Kong Islands?

Am J Disaster Med 2008 Jul-Aug;3(4):213-33

Bureau of Emergency Preparedness and Response, Arizona Department of Health Services, Tucson, USA.

Objective: Hazmat disaster preparedness is critical, especially as Hong Kong prepares for major international events, such as the 2008 Olympic Equestrian Games. No published medical study describes the identities and quantities of hazardous materials (HMs) in Hong Kong and lists what antidotes are needed for these dangerous goods (DGs). This study describes what HMs are most common in Hong Kong to prioritize disaster preparedness and training.

Design: A descriptive, cross-sectional study.

Setting: The Hong Kong Special Administrative Region, specifically Lantau, Lamma, and Hong Kong Islands.

Sample: The Hong Kong Fire Services Department (HKFSD) Dangerous Goods Database (DGD).

Interventions: Descriptive statistical analyses with Stata 9.2.

Main Outcome Measures: Identifying and quantifying HMs in the HKFSD DGD.

Results: Most HMs do not have antidotes. The most common HMs with recognized antidotes are carbon monoxide, methylene chloride, fluorides, cyanides, nitriles, hydrazine, methanol, and nitrates. The most common categories of DGs are substances giving off inflammable vapors, compressed gases, and corrosive and poisonous substances.

Conclusions: Hazmat disaster preparedness and training should emphasize these most common categories of DGs. Disaster planning should ensure adequate antidotes for HMs with recognized antidotes, ie, oxygen for carbon monoxide and methylene chloride; calcium gluconate and calcium chloride for fluorides; hydroxocobalamin or amyl nitrite, sodium nitrite, and sodium thiosulfate for cyanides and nitriles; pyridoxine for hydrazine; fomepizole or ethanol for methanol; and methylene blue for methemoglobinemia produced by nitrates. Supportive care is essential for patients exposed to HMs because most DGs do not have antidotes.
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October 2008

Evaluating trauma care capabilities in Mexico with the World Health Organization's Guidelines for Essential Trauma Care publication.

Rev Panam Salud Publica 2006 Feb;19(2):94-103

Secretaría de Salud, Sistema Estatal de Atención de Emergencias Médicas, Monterrey, Nuevo León, Mexico.

Objective: To identify affordable, sustainable methods to strengthen trauma care capabilities in Mexico, using the standards in the Guidelines for Essential Trauma Care, a publication that was developed by the World Health Organization and the International Society of Surgery to provide recommendations on elements of trauma care that should be in place in the various levels of health facilities in all countries.

Methods: The Guidelines publication was used as a basis for needs assessments conducted in 2003 and 2004 in three Mexican states. The states were selected to represent the range of geographic and economic conditions in the country: Oaxaca (south, lower economic status), Puebla (center, middle economic status), and Nuevo León (north, higher economic status). The sixteen facilities that were assessed included rural clinics, small hospitals, and large hospitals. Site visits incorporated direct inspection of physical resources as well as interviews with key administrative and clinical staff.

Results: Human and physical resources for trauma care were adequate in the hospitals, especially the larger ones. The survey did identify some deficiencies, such as shortages of stiff suction tips, pulse oximetry equipment, and some trauma-related medications. All of the clinics had difficulties with basic supplies for resuscitation, even though some received substantial numbers of trauma patients. In all levels of facilities there was room for improvement in administrative functions to assure quality trauma care, including trauma registries, trauma-related quality improvement programs, and uniform in-service training.

Conclusions: This study identified several low-cost ways to strengthen trauma care in Mexico. The study also highlighted the usefulness of the recommended norms in the Guidelines for Essential Trauma Care publication in providing a standardized template by which to assess trauma care capabilities in nations worldwide.
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February 2006