Publications by authors named "Jan Kyncl"

28 Publications

  • Page 1 of 1

Influence of air temperature and implemented veterinary measures on the incidence of human salmonellosis in the Czech Republic during 1998-2017.

BMC Public Health 2021 Jan 6;21(1):55. Epub 2021 Jan 6.

Department of Biostatistics, National Institute of Public Health, Prague, Czech Republic.

Background: The aim of our study was to analyse the influence of air temperature and implemented veterinary measures on salmonellosis incidence in the Czech Republic (CZ).

Methods: We conducted a descriptive analysis of salmonellosis as reported to the Czech national surveillance system during 1998-2017 and evaluated the influence of applied veterinary measures (started in January 2008) on salmonellosis incidence by comparing two 9-year periods (1998-2006, 2009-2017). Using a generalized additive model, we analysed association between monthly mean air temperature and log-transformed salmonellosis incidence over the entire twenty-year period.

Results: A total of 410,533 salmonellosis cases were reported during the study period in the CZ. Annual mean incidences of salmonellosis were 313.0/100,000 inhabitants before and 99.0/100,000 inhabitants after implementation of the veterinary measures. The time course of incidence was non-linear, with a sharp decline during 2006-2010. Significant association was found between disease incidence and air temperature. On average, the data indicated that within a common temperature range every 1 °C rise in air temperature contributed to a significant 6.2% increase in salmonellosis cases.

Conclusions: Significant non-linear effects of annual trend, within-year seasonality, and air temperature on the incidence of salmonellosis during 1998-2017 were found. Our study also demonstrates significant direct effect of preventive veterinary measures taken in poultry in reducing incidence of human salmonellosis in the CZ. The annual mean number of salmonellosis cases in the period after introducing the veterinary measures was only 32.5% of what it had been in the previous period.
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http://dx.doi.org/10.1186/s12889-020-10122-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7788966PMC
January 2021

Complicated hospitalization due to influenza: results from the Global Hospital Influenza Network for the 2017-2018 season.

BMC Infect Dis 2020 Jul 2;20(1):465. Epub 2020 Jul 2.

Institute of Health Metrics and Evaluation, Department of Health Metrics Sciences, University of Washington, Seattle, WA, USA.

Background: Since 2011, the Global Influenza Hospital Surveillance Network (GIHSN) has used active surveillance to prospectively collect epidemiological and virological data on patients hospitalized with influenza virus infection. Here, we describe influenza virus strain circulation in the GIHSN participant countries during 2017-2018 season and examine factors associated with complicated hospitalization among patients admitted with laboratory-confirmed influenza illness.

Methods: The study enrolled patients who were hospitalized in a GIHSN hospital in the previous 48 h with acute respiratory symptoms and who had symptoms consistent with influenza within the 7 days before admission. Enrolled patients were tested by reverse transcription-polymerase chain reaction to confirm influenza virus infection. "Complicated hospitalization" was defined as a need for mechanical ventilation, admission to an intensive care unit, or in-hospital death. In each of four age strata (< 15, 15-< 50, 50-< 65, and ≥ 65 years), factors associated with complicated hospitalization in influenza-positive patients were identified by mixed effects logistic regression and those associated with length of hospital stay using a linear mixed-effects regression model.

Results: The study included 12,803 hospitalized patients at 14 coordinating sites in 13 countries, of which 4306 (34%) tested positive for influenza. Influenza viruses B/Yamagata, A/H3N2, and A/H1N1pdm09 strains dominated and cocirculated, although the dominant strains varied between sites. Complicated hospitalization occurred in 10.6% of influenza-positive patients. Factors associated with complicated hospitalization in influenza-positive patients included chronic obstructive pulmonary disease (15-< 50 years and ≥ 65 years), diabetes (15-< 50 years), male sex (50-< 65 years), hospitalization during the last 12 months (50-< 65 years), and current smoking (≥65 years). Chronic obstructive pulmonary disease (50-< 65 years), other chronic conditions (15-< 50 years), influenza A (50-< 65 years), and hospitalization during the last 12 months (< 15 years) were associated with a longer hospital stay. The proportion of patients with complicated influenza did not differ between influenza A and B.

Conclusions: Complicated hospitalizations occurred in over 10% of patients hospitalized with influenza virus infection. Factors commonly associated with complicated or longer hospitalization differed by age group but commonly included chronic obstructive pulmonary disease, diabetes, and hospitalization during the last 12 months.
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http://dx.doi.org/10.1186/s12879-020-05167-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7330273PMC
July 2020

Determinants of Fatal Outcome in Patients Admitted to Intensive Care Units With Influenza, European Union 2009-2017.

Open Forum Infect Dis 2019 Nov 29;6(11):ofz462. Epub 2019 Oct 29.

Office of the Chief Scientist, European Centre for Disease Prevention and Control (ECDC), Solna, Sweden.

Background: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication.

Methods: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017.

Results: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women.

Conclusions: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions.
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http://dx.doi.org/10.1093/ofid/ofz462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105050PMC
November 2019

Vaccination of healthcare personnel in Europe: Update to current policies.

Vaccine 2019 12 14;37(52):7576-7584. Epub 2019 Oct 14.

Director, Mayo Vaccine Research Group, Mayo Clinic, Rochester, MN, United States.

We investigated and compared current national vaccination policies for health-care personnel (HCP) in Europe with results from our previous survey. Data from 36 European countries were collected using the same methodology as in 2011. National policies for HCP immunization were in place in all countries. There were significant differences in terms of number of vaccinations, target HCP and healthcare settings, and implementation regulations (recommended or mandatory vaccinations). Vaccination policies against hepatitis B and seasonal influenza were present in 35 countries each. Policies for vaccination of HCP against measles, mumps, rubella and varicella existed in 28, 24, 25 and 19 countries, respectively; and against tetanus, diphtheria, pertussis and poliomyelitis in 21, 20, 19, and 18 countries, respectively. Recommendations for hepatitis A immunization existed in 17 countries, and against meningococcus B, meningococcus C, meningococcus A, C, W, Y, and tuberculosis in 10, 8, 17, and 7 countries, respectively. Mandatory vaccination policies were found in 13 countries and were a pre-requisite for employment in ten. Comparing the vaccination programs of the 30 European countries that participated in the 2011 survey, we found that more countries had national vaccination policies against measles, mumps, rubella, hepatitis A, diphtheria, tetanus, poliomyelitis, pertussis, meningococcus C and/or meningococcus A, C, W, Y; and more of these implemented mandatory vaccination policies for HCP. In conclusion, European countries now have more comprehensive national vaccination programs for HCP, however there are still gaps. Given the recent large outbreaks of vaccine-preventable diseases in Europe and the occupational risk for HCP, vaccination policies need to be expanded and strengthened in several European countries. Overall, vaccination policies for HCP in Europe should be periodically re-evaluated in order to provide optimal protection against vaccine-preventable diseases and infection control within healthcare facilities for HCP and patients.
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http://dx.doi.org/10.1016/j.vaccine.2019.09.061DOI Listing
December 2019

Influenza epidemiology and influenza vaccine effectiveness during the 2015-2016 season: results from the Global Influenza Hospital Surveillance Network.

BMC Infect Dis 2019 May 14;19(1):415. Epub 2019 May 14.

Research Institute of Influenza, WHO National Influenza Centre of Russia and Ministry of Healthcare of the Russian Federation, St. Petersburg, Russian Federation.

Background: The Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization.

Methods: During the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach.

Results: 9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were < 5 years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, - 3.6 to 32.2) overall, 23.0% (95% CI, - 3.3 to 42.6) against A(H1N1)pdm09, and - 25.6% (95% CI, - 86.3 to 15.4) against B/Victoria lineage.

Conclusions: The 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.
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http://dx.doi.org/10.1186/s12879-019-4017-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518734PMC
May 2019

Influenza epidemiology and influenza vaccine effectiveness during the 2016-2017 season in the Global Influenza Hospital Surveillance Network (GIHSN).

BMC Public Health 2019 May 2;19(1):487. Epub 2019 May 2.

Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), 21 Cataluña Av, 46020, Valencia, Spain.

Background: The Global Influenza Hospital Surveillance Network (GIHSN) aims to determine the burden of severe influenza disease and Influenza Vaccine Effectiveness (IVE). This is a prospective, active surveillance and hospital-based epidemiological study to collect epidemiological data in the GIHSN. In the 2016-2017 influenza season, 15 sites in 14 countries participated in the GIHSN, although the analyses could not be performed in 2 sites. A common core protocol was used in order to make results comparable. Here we present the results of the GIHSN 2016-2017 influenza season.

Methods: A RT-PCR test was performed to all patients that accomplished the requirements detailed on a common core protocol. Patients admitted were included in the study after signing the informed consent, if they were residents, not institutionalised, not discharged in the previous 30 days from other hospitalisation with symptoms onset within the 7 days prior to admission. Patients 5 years old or more must also complied the Influenza-Like Illness definition. A test negative-design was implemented to perform IVE analysis. IVE was estimated using a logistic regression model, with the formula IVE = (1-aOR) × 100, where aOR is the adjusted Odds Ratio comparing cases and controls.

Results: Among 21,967 screened patients, 10,140 (46.16%) were included, as they accomplished the inclusion criteria, and tested, and therefore 11,827 (53.84%) patients were excluded. Around 60% of all patients included with laboratory results were recruited at 3 sites. The predominant strain was A(H3N2), detected in 63.6% of the cases (1840 patients), followed by B/Victoria, in 21.3% of the cases (618 patients). There were 2895 influenza positive patients (28.6% of the included patients). A(H1N1)pdm09 strain was mainly found in Mexico. IVE could only be performed in 6 sites separately. Overall IVE was 27.24 (95% CI 15.62-37.27. Vaccination seemed to confer better protection against influenza B and in people 2-4 years, or 85 years old or older. The aOR for hospitalized and testing positive for influenza was 3.02 (95% CI 1.59-5.76) comparing pregnant with non-pregnant women.

Conclusions: Vaccination prevented around 1 in 4 hospitalisations with influenza. Sparse numbers didn't allow estimating IVE in all sites separately. Pregnancy was found a risk factor for influenza, having 3 times more risk of being admitted with influenza for pregnant women.
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http://dx.doi.org/10.1186/s12889-019-6713-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6498567PMC
May 2019

Circulation of influenza A and B in the Czech Republic from 2000-2001 to 2015-2016.

BMC Infect Dis 2019 Feb 14;19(1):160. Epub 2019 Feb 14.

Department of Infectious Diseases Epidemiology, National Institute of Public Health, Prague, Czech Republic.

Background: To improve national influenza vaccination recommendations, additional data on influenza A and B virus circulation are needed. Here, we describe the circulation of influenza A and B in the Czech Republic during 16 seasons.

Methods: This was a retrospective analysis of data collected from the 2000-2001 to 2015-2016 influenza seasons by the Czech Republic national influenza surveillance network. Influenza was confirmed and viral isolates subtyped by virological assays followed by antigen detection or by reverse transcriptase-polymerase chain reaction.

Results: Of 16,940 samples collected, 5144 (30.4%) were influenza-positive. Influenza A represented 78.6% of positive cases overall and accounted for more than 55.0% of all influenza cases in every season, except for 2005-2006 (6.0%). Both A/H1N1 and A/H3N2 were detected in most seasons, except for 2001-2002 and 2003-2004 (only A/H3N2), and 2007-2008 and 2009-2010 (only A/H1N1). Influenza B represented 21.4% of positive cases overall (range, 0.0-94.0% per season). Both influenza B lineages were detected in three seasons, a single B lineage in 11, and no B strain in two. For the 11 seasons where influenza B accounted for ≥20% of positive cases, the dominant lineage was Yamagata in six and Victoria in four. In the remaining season, the two lineages co-circulated. For two seasons (2005-2006 and 2007-2008), the B lineage in the trivalent influenza vaccine did not match the dominant circulating B lineage.

Conclusions: In the Czech Republic, during the 2000-2001 to 2015-2016 influenza seasons, influenza virus circulation varied considerably. Although influenza A accounted for the most cases in almost all seasons, influenza B made a substantial, sometimes dominant, contribution to influenza disease.
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http://dx.doi.org/10.1186/s12879-019-3783-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376715PMC
February 2019

Impact of European vaccination policies on seasonal influenza vaccination coverage rates: An update seven years later.

Hum Vaccin Immunother 2018 27;14(11):2706-2714. Epub 2018 Aug 27.

l Royal College of General Practitioners , Wokingham , Berkshire , UK.

Seasonal influenza can have serious morbid consequences and can even result in death, particularly in at-risk populations, including healthcare professionals (HCPs), elderly and those living with a medical risk condition. Although in Europe recommendations exist for annual influenza vaccination in these populations in most countries, the vaccination coverage rate (VCR) is often well below the World Health Organization target of 75% coverage. In our previous survey in 2009 we showed that some elements of national vaccination policies, e.g. reminder systems, strong official recommendation, and easy access, seemed to contribute to achieving higher influenza VCRs among elderly. We repeated the survey in 2016, using the same methodology to assess changes in influenza VCRs among the elderly and in the impact of policy elements on these VCRs. In addition, we collected information about VCRs among HCPs, and those living with a medical risk condition. The median VCR in the 21 countries that had recommendations for influenza vaccination in the elderly was 35.3%, ranging from 1.1% in Estonia to 74.5% in Scotland. The average VCRs for HCPs and those living with medical risk conditions, available in 17 and 10 countries, respectively, were 28.3% (range 7% in Czech Republic to 59.1% in Portugal) and 32.2% (range from 20.0% in the Czech Republic and Hungary to 59.6% in Portugal), respectively. Fewer countries were able to provide data from HCP and those living with medical risk conditions. Since the initial survey during the 2007-2008 influenza season, VCRs have decreased in the elderly in the majority of countries, thus, achieving high VCRs in the elderly and the other target groups is still a major public health challenge in Europe. This could be addressed by the identification, assessment and sharing of best practice for influenza vaccination policies.
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http://dx.doi.org/10.1080/21645515.2018.1489948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6314402PMC
June 2019

Motors of influenza vaccination uptake and vaccination advocacy in healthcare workers: A comparative study in six European countries.

Vaccine 2018 10 28;36(44):6546-6552. Epub 2018 Mar 28.

Kingston University, London, United Kingdom. Electronic address:

Background: Annual vaccination is the most effective way to prevent and control the health and economic burden caused by seasonal influenza. Healthcare workers (HCWs) play a crucial role in vaccine acceptance and advocacy for their patients. This study explored the drivers of HCWs' vaccine acceptance and advocacy in six European countries.

Methods: Healthcare workers (mainly general practitioners, specialist physicians, and nurses) voluntarily completed a questionnaire in Bulgaria (N = 485), Czech Republic (N = 518), Kosovo (N = 466), Poland (N = 772), Romania (N = 155), and the United Kingdom (N = 80). Twelve-item scales were used to analyse sentiment clusters for influenza vaccination acceptance and engagement with vaccination advocacy. Past vaccination behaviour and patient recommendation were also evaluated. All data were included in a single analysis.

Results: For vaccination acceptance, the main cluster (engaged sentiment: 68%) showed strong positive attitudes for influenza vaccination. A second cluster (hesitant sentiment: 32%) showed more neutral attitudes. Cluster membership was predicted by country of origin and age. The odds ratio for past vaccination in the engaged cluster was 39.6 (95% CI 12.21-128.56) although this varied between countries. For vaccination advocacy, the main cluster (confident sentiment: 73%) showed strong positive attitudes towards advocacy; a second cluster (diffident sentiment: 27%) showed neutral attitudes. Cluster membership was predicted by country of origin, age and profession, with specialist physicians being the least likely to belong to the confident sentiment cluster. HCWs characterised by confident advocacy sentiments were also more likely recommend flu vaccination. Again, this association was moderated by country of origin.

Conclusions: These data show that there is room to improve both vaccination acceptance and advocacy rates in European HCWs, which would be expected to lead to higher rates of HCW vaccination. Benefits that could be expected from such an outcome are improved advocacy and better control of morbidity and mortality related to seasonal influenza infection.
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http://dx.doi.org/10.1016/j.vaccine.2018.02.031DOI Listing
October 2018

Estimates of global seasonal influenza-associated respiratory mortality: a modelling study.

Lancet 2018 03 14;391(10127):1285-1300. Epub 2017 Dec 14.

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

Background: Estimates of influenza-associated mortality are important for national and international decision making on public health priorities. Previous estimates of 250 000-500 000 annual influenza deaths are outdated. We updated the estimated number of global annual influenza-associated respiratory deaths using country-specific influenza-associated excess respiratory mortality estimates from 1999-2015.

Methods: We estimated country-specific influenza-associated respiratory excess mortality rates (EMR) for 33 countries using time series log-linear regression models with vital death records and influenza surveillance data. To extrapolate estimates to countries without data, we divided countries into three analytic divisions for three age groups (<65 years, 65-74 years, and ≥75 years) using WHO Global Health Estimate (GHE) respiratory infection mortality rates. We calculated mortality rate ratios (MRR) to account for differences in risk of influenza death across countries by comparing GHE respiratory infection mortality rates from countries without EMR estimates with those with estimates. To calculate death estimates for individual countries within each age-specific analytic division, we multiplied randomly selected mean annual EMRs by the country's MRR and population. Global 95% credible interval (CrI) estimates were obtained from the posterior distribution of the sum of country-specific estimates to represent the range of possible influenza-associated deaths in a season or year. We calculated influenza-associated deaths for children younger than 5 years for 92 countries with high rates of mortality due to respiratory infection using the same methods.

Findings: EMR-contributing countries represented 57% of the global population. The estimated mean annual influenza-associated respiratory EMR ranged from 0·1 to 6·4 per 100 000 individuals for people younger than 65 years, 2·9 to 44·0 per 100 000 individuals for people aged between 65 and 74 years, and 17·9 to 223·5 per 100 000 for people older than 75 years. We estimated that 291 243-645 832 seasonal influenza-associated respiratory deaths (4·0-8·8 per 100 000 individuals) occur annually. The highest mortality rates were estimated in sub-Saharan Africa (2·8-16·5 per 100 000 individuals), southeast Asia (3·5-9·2 per 100 000 individuals), and among people aged 75 years or older (51·3-99·4 per 100 000 individuals). For 92 countries, we estimated that among children younger than 5 years, 9243-105 690 influenza-associated respiratory deaths occur annually.

Interpretation: These global influenza-associated respiratory mortality estimates are higher than previously reported, suggesting that previous estimates might have underestimated disease burden. The contribution of non-respiratory causes of death to global influenza-associated mortality should be investigated.

Funding: None.
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http://dx.doi.org/10.1016/S0140-6736(17)33293-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935243PMC
March 2018

Analysis of the seasonal incidence of acute respiratory infections including influenza (ARI) in the Czech Republic - possible contribution of the functional data boxplot in epidemiology.

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2017 Dec 17;161(4):381-388. Epub 2017 Oct 17.

Department of Infectious Diseases Epidemiology, Centre for Epidemiology and Microbiology, National Institute of Public Health, Prague, Czech Republic.

Aims: The detection of an epidemic outbreak is possible only if the baseline incidence level of a given disease is well defined. The determination of the baseline is complicated by the presence of epidemic outbreaks in historical data. The aim of the paper is to provide a new way of determining the baseline.

Methods: The analyzed data containing weekly records on the incidence of acute respiratory infections including influenza (ARI) in the Czech Republic and its regions are taken from the nationwide surveillance system; data on 15 seasons from 2001/02 to 2015/16 are included. Functional boxplots of the data are constructed and five distinct methods (componentwise mean, componentwise median, median, trimmed mean, and adjusted mean) were used for the computation of the baseline level function.

Results: It was shown that the methods based on functional data analysis could successfully overcome the problems that arise when the conventional methods are used for the determination of the baseline function.

Conclusion: The functional boxplot - a new statistical tool - can bring not only a transparent visualisation of comprehensive data, but can also help epidemiologists and other public health experts to determine the baseline incidence level of a given disease as well as to detect unusual epidemic seasons.
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http://dx.doi.org/10.5507/bp.2017.042DOI Listing
December 2017

Estimating the Baseline Incidence of a Seasonal Disease Independently of Epidemic Outbreaks.

Cent Eur J Public Health 2016 09;24(3):199-205

Unit for Infectious Diseases Epidemiology, National Institute of Public Health, Prague, Czech Republic.

In epidemiology, it is very important to estimate the baseline incidence of infectious diseases, but the available data are often subject to outliers due to epidemic outbreaks. Consequently, the estimate of the baseline incidence is biased and so is the predicted epidemic threshold which is a crucial reference indicator used to suspect and detect an epidemic outbreak. Another problem is that the "usual" incidence varies in a season dependent manner, i.e. it may not be constant throughout the year, is often periodic, and may also show a trend between years. To take account of these factors, more complicated models adjusted for outliers are used. If not adjusted for outliers, the baseline incidence estimate is biased. As a result, the epidemic threshold can be overestimated and thus can make the detection of an epidemic outbreak more difficult. Classical Serfling's model is based on the sine function with a phase shift and amplitude. Multiple approaches are applied to model the long-term and seasonal trends. Nevertheless, none of them controls for the effect of epidemic outbreaks. The present article deals with the adjustment of the data biased by epidemic outbreaks. Some models adjusted for outliers, i.e. for the effect of epidemic outbreaks, are presented. A possible option is to remove the epidemic weeks from the analysis, but consequently, in some calendar weeks, data will only be available for a small number of years. Furthermore, the detection of an epidemic outbreak by experts (epidemiologists and microbiologists) will be compared with that in various models.
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http://dx.doi.org/10.21101/cejph.a4800DOI Listing
September 2016

Influenza epidemiology and influenza vaccine effectiveness during the 2014-2015 season: annual report from the Global Influenza Hospital Surveillance Network.

BMC Public Health 2016 08 22;16 Suppl 1:757. Epub 2016 Aug 22.

Research Institute of Influenza, Saint Petersburg, Russian Federation, Russia.

The Global Influenza Hospital Surveillance Network (GIHSN) has established a prospective, active surveillance, hospital-based epidemiological study to collect epidemiological and virological data for the Northern and Southern Hemispheres over several consecutive seasons. It focuses exclusively on severe cases of influenza requiring hospitalization. A standard protocol is shared between sites allowing comparison and pooling of results. During the 2014-2015 influenza season, the GIHSN included seven coordinating sites from six countries (St. Petersburg and Moscow, Russian Federation; Prague, Czech Republic; Istanbul, Turkey; Beijing, China; Valencia, Spain; and Rio de Janeiro, Brazil). Here, we present the detailed epidemiological and influenza vaccine effectiveness findings for the Northern Hemisphere 2014-2015 influenza season.
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http://dx.doi.org/10.1186/s12889-016-3378-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5001209PMC
August 2016

Influenza vaccination: key facts for general practitioners in Europe-a synthesis by European experts based on national guidelines and best practices in the United Kingdom and the Netherlands.

Drugs Context 2016 3;5:212293. Epub 2016 Aug 3.

General Practitioner in Amersfoort, The Netherlands.

Currently there is no influenza vaccination guidance for European general practitioners. Furthermore, although the European Council recommends a target seasonal influenza vaccination rate of 75% in the elderly (65 years and above) and in anyone aged >6 months with a chronic medical condition, there remain wide discrepancies throughout Europe. A harmonised guideline regarding not only vaccination strategy but also for the consistent diagnosis of influenza across Europe is essential to support a common approach for the implementation of seasonal influenza vaccination across Europe. This document is based on pre-existing guidelines available in the UK and Netherlands and has been approved by a group of European experts for use throughout Europe. As well as providing a standardised influenza diagnosis, it also reviews the current recommendations for influenza vaccination, the types of vaccine available, the contraindications, vaccine use in special populations (in pregnancy, children, and in those with egg allergy), and concomitant administration with other vaccines. The effectiveness, safety, and timing of the seasonal influenza vaccine are also reviewed. A second section provides practical guidance for general practitioners for the implementation of a seasonal influenza vaccination program, including the selection and notification of those eligible for vaccination, as well as suggestions for the organisation of a vaccination programme. Finally, suggested responses to common patient misconceptions and frequently asked questions are included. The aim of this article is to harmonise the diagnosis of seasonal influenza and the approach of European general practitioners to seasonal influenza vaccination in order to better identify influenza outbreaks and to move towards reaching the target vaccination rate of 75% throughout Europe.
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http://dx.doi.org/10.7573/dic.212293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974050PMC
August 2016

Mumps in the Czech Republic in 2013: Clinical Characteristics, Mumps Virus Genotyping, and Epidemiological Links.

Cent Eur J Public Health 2016 Mar;24(1):22-8

Clinic for Infectious, Parasitic and Tropical Diseases, Na Bulovce Hospital, Prague, Czech Republic.

Aim: The aim of the study was to map the incidence of mumps in the Czech Republic in terms of clinical symptoms, epidemiological links, and characteristics of circulating genotypes.

Methods: Patients with suspected mumps examined in the Infectious Diseases Clinic of the Na Bulovce Hospital in 2013 were enrolled in the study. Buccal swab specimens were tested by means of nucleic acid detection (RT-qPCR) and when positive, they were cultured in tissue culture. Sequencing was carried out using the BigDye Terminator v3.1 Cycle Sequencing Kit and Genetic Analyzer 3500. The SeqScape software was used for the analysis of sequencing data and filtering out low quality reads. The phylogenetic analysis and genotyping were performed using the Mega 6 software. To generate the phylogenetic tree, all sequences were aligned by the MAFFT tool and the alignment obtained was edited using the BioEdit software. In all patients, selected biochemical markers (C-reactive protein, white blood cell count and serum amylase) were measured. The EPIDAT system used for reporting infectious diseases, record keeping, and data analysis in the Czech Republic was the source of statistical data.

Results: Eighty-nine patients with suspected mumps were examined in the Na Bulovce Hospital and 65 of them were laboratory confirmed with mumps: 40 males (61.5%) and 25 females (38.5%). The mean age of the study cohort was 25.9 years (median age of 23 years, age range from 10 to 73 years) and 14 patients were under 18 years of age. Thirty-four (52.3%) patients were vaccinated in childhood, 28 (43.1%) were unvaccinated, and for three persons, vaccination data were not available. A severe course of the disease was reported in 15 (23.1%) patients. Fourteen of them needed hospitalization because of orchitis (9 males) and meningitis (5 patients). One patient with orchitis was treated on an outpatient basis. The need for hospitalization tended to be lower in the unvaccinated patients (14.7% vs. 35.7%, p=0.076). In 2013, 1,553 cases of mumps were reported to the EPIDAT system. Of these, 640 were laboratory confirmed. The most often reported complications were orchitis (90 cases, i.e. 10.3%) and meningitis (21 cases, i.e. 1.4%). Orchitis was diagnosed in 30.3% of the unvaccinated and in 6.4% of the vaccinated males. Meningitis occurred in 3.1% of the unvaccinated and in 1.0% of the vaccinated patients.

Conclusion: Despite the emergence of mumps among the vaccinated population, the present study has confirmed a positive effect of the vaccine, particularly on the incidence of complications and inflammatory markers. All 30 sequenced mumps virus strains were assigned to group G. A secondary vaccine failure due to waning immunity seems to be a plausible explanation for the rise in mumps cases.
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http://dx.doi.org/10.21101/cejph.a4512DOI Listing
March 2016

Protective effect of vaccination against mumps complications, Czech Republic, 2007-2012.

BMC Public Health 2016 Apr 1;16:293. Epub 2016 Apr 1.

Department of Infectious Diseases Epidemiology, Centre for Epidemiology and Microbiology, National Institute of Public Health, Šrobárova 48, 10042, Prague, Czech Republic.

Background: In the Czech Republic, two-dose immunization against mumps achieves 98% coverage. The routine reporting detects mumps cases, clinical complications, and hospital admissions in unvaccinated but also in vaccinated individuals. Using surveillance data of patients with mumps we assessed the effectiveness of mumps vaccination on mumps clinical complications and hospitalization need. We also investigated the effect of the time since immunization.

Methods: We analysed data on incident mumps cases reported to the Czech national surveillance system in 2007-2012. Using a logistic regression model with adjustment for age, sex, year of onset, and the administrative region, the association between vaccination and the most frequent mumps complications and hospitalization was evaluated. The adjusted odds ratios (ORa) for mumps complications were compared between the vaccinated and non-vaccinated groups, reflecting the vaccine effectiveness (VEa) computed as VEa = (1-ORa) × 100. We estimated the risk of mumps complications by the time from vaccination.

Results: From total of 9663 mumps analysed cases 5600 (58%) occurred in males. The mean age at the disease onset was 17.3, median 16 years. Ninety percent of the study patients had no complications, while 1.6% developed meningitis, 0.2% encephalitis, and 0.6% pancreatitis. Mumps orchitis occurred in 659 (11.8%) male cases. In total, 1192 (12.3%) patients required hospitalization. Two doses of vaccine received by 81.8% cases significantly reduced the risk of hospitalization: ORa 0.29 (95% CI: 0.24, 0.35). Two doses showed statistically significant VEa 64% (95% CI: 46, 79) for meningitis, 93% (95% CI: 66, 98) for encephalitis in all cases, and 72% (95% CI: 64, 78) for orchitis in males. Vaccine effectiveness for orchitis declined from 81 to 74% and 56% in the most affected age groups 10-14, 15-19, and 20-24 years, respectively. Among 7850 two-dose recipients, the rate of complications rose from below 1 to 16% in categories up to 6 years and 24 and more years after the second dose, respectively.

Conclusions: This study demonstrates a significant preventive effect of two-dose vaccination against mumps complications (orchitis, meningitis, or encephalitis) and hospitalization for mumps. The risk of complications increases with time interval from vaccination. Teenagers and young adults were the most affected age groups.
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http://dx.doi.org/10.1186/s12889-016-2958-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818515PMC
April 2016

Estimating the Baseline and Threshold for the Incidence of Diseases with Seasonal and Long-Term Trends.

Cent Eur J Public Health 2015 Dec;23(4):352-9

Department of Infectious Diseases Epidemiology, Centre for Epidemiology and Microbiology, National Institute of Public Health, Prague, CzechRepublic.

In epidemiology, it is very important to estimate the baseline incidence of infectious diseases. From this baseline, the epidemic threshold can be derived as a clue to recognize an excess incidence, i.e. to detect an epidemic by mathematical methods. Nevertheless, a problem is posed by the fact that the incidence may vary during the year, as a rule, in a season dependent manner. To model the incidence of a disease, some authors use seasonal trend models. For instance, Serfling applies the sine function with a phase shift and amplitude. A similar model based on the analysis of variance with kernel smoothing and Serfling's higher order models, i.e. models composed of multiple sine-cosine function pairs with a variably long period, will be presented below. Serfling's model uses a long-term linear trend, but the linearity may not be always acceptable. Therefore, a more complex, long-term trend estimation will also be addressed, using different smoothing methods. In addition, the issue of the time unit (mostly a week) used in describing the incidence is discussed.
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http://dx.doi.org/10.21101/cejph.a4392DOI Listing
December 2015

Dengue fever in Czech travellers: A 10-year retrospective study in a tertiary care centre.

Travel Med Infect Dis 2016 Jan-Feb;14(1):32-38. Epub 2015 Jun 25.

1st Department of Infectious Diseases, 2nd Medical Faculty, Charles University in Prague, Budínova 2, 180 81 Prague, Czech Republic; Department of Infectious, Parasitic and Tropical Diseases, Hospital Na Bulovce, Budínova 2, 180 81 Prague, Czech Republic; Institute of Immunology and Microbiology, 1st Medical Faculty, Charles University in Prague, Studničkova 7, 128 00 Prague, Czech Republic; Department of Infectious Diseases, Regional Hospital Liberec, Husova 10, 460 63 Liberec, Czech Republic.

Background: Dengue fever is a frequent cause of morbidity in travellers. The objective was to describe the epidemiological and clinical characteristics of dengue fever in Czech travellers.

Method: This descriptive study includes patients with acute dengue fever diagnosed at Hospital Na Bulovce during 2004-2013. Data were collected and analysed retrospectively.

Results: A total of 132 patients (83 males and 49 females) of median age 33 years (IQR 29-40) were included. Diagnosis was established by NS1 antigen detection in 87/107 cases (81.3%) and/or RT-PCR in 50/72 (69.4%) and by serology in 25 cases (18.9%). Dengue was acquired in South-East Asia in 69 cases (52.3%), followed by South Asia (48 cases; 36.3%), Latin America (14; 10.6%) and Sub-Saharan Africa (1; 0.8%). The most frequent symptoms included fever, rash and headache. Initial leukocyte and lymphocyte counts were lower in patients who presented in the early phase (0-4 days), however, platelet count was lower and AST, ALT and LDH activity higher in patients with a longer symptoms duration (≥5 days). The clinical course was mostly uncomplicated.

Conclusions: Dengue fever is becoming a frequent cause of fever in Czech travellers. Clinicians should be familiar with the typical clinical findings and novel diagnostic methods.
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http://dx.doi.org/10.1016/j.tmaid.2015.06.005DOI Listing
December 2016

Contrasting patterns of hot spell effects on morbidity and mortality for cardiovascular diseases in the Czech Republic, 1994-2009.

Int J Biometeorol 2015 Nov 6;59(11):1673-84. Epub 2015 Mar 6.

Institute of Atmospheric Physics, The Czech Academy of Sciences, Boční II 1401, 141 31, Prague, Czech Republic.

The study examines effects of hot spells on cardiovascular disease (CVD) morbidity and mortality in the population of the Czech Republic, with emphasis on differences between ischaemic heart disease (IHD) and cerebrovascular disease (CD) and between morbidity and mortality. Daily data on CVD morbidity (hospital admissions) and mortality over 1994-2009 were obtained from national hospitalization and mortality registers and standardized to account for long-term changes as well as seasonal and weekly cycles. Hot spells were defined as periods of at least two consecutive days with average daily air temperature anomalies above the 95% quantile during June to August. Relative deviations of mortality and morbidity from the baseline were evaluated. Hot spells were associated with excess mortality for all examined cardiovascular causes (CVD, IHD and CD). The increases were more pronounced for CD than IHD mortality in most population groups, mainly in males. In the younger population (0-64 years), however, significant excess mortality was observed for IHD while there was no excess mortality for CD. A short-term displacement effect was found to be much larger for mortality due to CD than IHD. Excess CVD mortality was not accompanied by increases in hospital admissions and below-expected-levels of morbidity prevailed during hot spells, particularly for IHD in the elderly. This suggests that out-of-hospital deaths represent a major part of excess CVD mortality during heat and that for in-hospital excess deaths CVD is a masked comorbid condition rather than the primary diagnosis responsible for hospitalization.
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http://dx.doi.org/10.1007/s00484-015-0974-1DOI Listing
November 2015

Impacts of hot and cold spells differ for acute and chronic ischaemic heart diseases.

BMC Public Health 2014 May 21;14:480. Epub 2014 May 21.

Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.

Background: Many studies have reported associations between temperature extremes and cardiovascular mortality but little has been understood about differences in the effects on acute and chronic diseases. The present study examines hot and cold spell effects on ischaemic heart disease (IHD) mortality in the Czech Republic during 1994-2009, with emphasis upon differences in the effects on acute myocardial infarction (AMI) and chronic IHD.

Methods: We use analogous definitions for hot and cold spells based on quantiles of daily average temperature anomalies, thus allowing for comparison of results for summer hot spells and winter cold spells. Daily mortality data were standardised to account for the long-term trend and the seasonal and weekly cycles. Periods when the data were affected by epidemics of influenza and other acute respiratory infections were removed from the analysis.

Results: Both hot and cold spells were associated with excess IHD mortality. For hot spells, chronic IHD was responsible for most IHD excess deaths in both male and female populations, and the impacts were much more pronounced in the 65+ years age group. The excess mortality from AMI was much lower compared to chronic IHD mortality during hot spells. For cold spells, by contrast, the relative excess IHD mortality was most pronounced in the younger age group (0-64 years), and we found different pattern for chronic IHD and AMI, with larger effects on AMI.

Conclusions: The findings show that while excess deaths due to IHD during hot spells are mainly of persons with chronic diseases whose health had already been compromised, cardiovascular changes induced by cold stress may result in deaths from acute coronary events rather than chronic IHD, and this effect is important also in the younger population. This suggests that the most vulnerable population groups as well as the most affected cardiovascular diseases differ between hot and cold spells, which needs to be taken into account when designing and implementing preventive actions.
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http://dx.doi.org/10.1186/1471-2458-14-480DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4038364PMC
May 2014

Medical and economic burden of influenza in the elderly population in central and eastern European countries.

Hum Vaccin Immunother 2014 28;10(2):428-40. Epub 2013 Oct 28.

Sanofi Pasteur; Lyon, France.

Influenza affects 5-15% of the population during an epidemic. In Western Europe, vaccination of at-risk groups forms the cornerstone of influenza prevention. However, vaccination coverage of the elderly (> 65 y) is often low in Central and Eastern Europe (CEE); potentially because a paucity of country-specific data limits evidence-based policy making. Therefore the medical and economic burden of influenza were estimated in elderly populations in the Czech Republic, Hungary, Kazakhstan, Poland, Romania, and Ukraine. Data covering national influenza vaccination policies, surveillance and reporting, healthcare costs, populations, and epidemiology were obtained via literature review, open-access websites and databases, and interviews with experts. A simplified model of patient treatment flow incorporating cost, population, and incidence/prevalence data was used to calculate the influenza burden per country. In the elderly, influenza represented a large burden on the assessed healthcare systems, with yearly excess hospitalization rates of ~30/100,000. Burden varied between countries and was likely influenced by population size, surveillance system, healthcare provision, and vaccine coverage. The greatest burden was found in Poland, where direct costs were over EUR 5 million. Substantial differences in data availability and quality were identified, and to fully quantify the burden of influenza in CEE, influenza reporting systems should be standardized. This study most probably underestimates the real burden of influenza, however the public health problem is recognized worldwide, and will further increase with population aging. Extending influenza vaccination of the elderly may be a cost-effective way to reduce the burden of influenza in CEE.
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http://dx.doi.org/10.4161/hv.26886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4185899PMC
January 2015

[Phylogenetic analysis and genotyping of A/H3N2 Influenza viruses isolated from patients hospitalised with influenza-like illness symptoms in the na bulovce hospital in the season 2011/2012].

Epidemiol Mikrobiol Imunol 2013 Apr;62(1):4-8

Státní Zdravotní ústav, Centrum Epidemiologie a Mikrobiologie, Praha.

Influenza A virus is an important cause of acute respiratory infections (ARI). Clinical manifestations of ARI vary from mild or moderate to life-threatening conditions requiring intensive care. Given the segmented genome, a large natural reservoir of other influenza virus subtypes, and antibody selection pressure in the population, the virus is variable and genetically unstable. The phylogenetic analysis and genotyping of A/H3N2 influenza viruses isolated from patients hospitalised with influenza-like illness symptoms in the Na Bulovce Hospital in the season 2011/2012 support the assumption that the pathogenicity is a polygenic trait modifiable by the host health status and seems not to be unambiguously associated with any specific mutations.
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April 2013

Clinical and laboratory features of viral hepatitis A in children.

Wien Klin Wochenschr 2013 Feb 29;125(3-4):83-90. Epub 2013 Jan 29.

1st Department of Infectious Diseases, 2nd Medical Faculty, Hospital Na Bulovce Charles University in Prague, Budinova 2, 18081 Prague, Czech Republic.

Recent outbreaks of viral hepatitis A in non-endemic European countries and the potential outbreak risk in susceptible populations has led us to evaluate the clinical characteristics of children hospitalised with hepatitis A. Retrospective study included 118 children (68 boys and 50 girls) with the mean age of 8.5 years hospitalised at Hospital Na Bulovce in Prague from June 2008 to June 2009. The clinical course was symptomatic icteric in 57 (48.3 %) children, symptomatic anicteric in 23 (19.5 %), subclinical in 22 (18.6 %) and asymptomatic inapparent in 16 (13.6 %). The relapse of the disease occurred in three patients. There were no cases of fulminant hepatitis. The most frequent symptoms included jaundice (57 cases), abdominal pain/discomfort (38), vomiting (38), dark urine (37), subfebrility (29) and fever (25). Hepatic injury markers were substantially elevated in icteric patients, but moderate elevations were identified in anicteric and subclinical cases as well. Lower white blood cell and lymphocyte counts were independently associated with symptomatic and more severe clinical course. Active immunisation was provided to 22 patients, and as a post-exposure prophylaxis to 19 of them. The clinical course and laboratory parameters in vaccinated children were not significantly different from non-vaccinated children. The clinical course of hepatitis A was largely self-limiting and benign. Asymptomatic infections are frequent, representing risk for disease spread; however, they are associated with elevations of hepatic injury markers. The inclusion of significant proportion of asymptomatic cases that were identified and investigated only because of active epidemiological surveillance in the outbreak focus represents the particular asset of this study.
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http://dx.doi.org/10.1007/s00508-012-0316-9DOI Listing
February 2013

[Basic epidemiological characteristics of influenza infection].

Klin Mikrobiol Infekc Lek 2010 Aug;16(4):116-9

Department of Infectious Diseases Epidemiology, National Institute of Public Health, Prague, Czech Republic.

Influenza is a relatively serious infection that affects hundreds of thousands of people every year in the Czech Republic alone, with unnecessary deaths as a possible outcome. Vaccination against influenza is the most important preventive measure. The highest incidence of seasonal influenza is reported in school-age children and young adults while the highest mortality is observed among the elderly. Pandemic influenza may significantly differ from seasonal influenza in these two aspects. Other epidemiological characteristics of seasonal influenza are presented and compared with those of 2009 pandemic A/H1N1 ("Mexican") influenza that caused the first pandemic of the 21st century.
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August 2010

Excess cardiovascular mortality associated with cold spells in the Czech Republic.

BMC Public Health 2009 Jan 15;9:19. Epub 2009 Jan 15.

Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.

Background: The association between cardiovascular mortality and winter cold spells was evaluated in the population of the Czech Republic over 21-yr period 1986-2006. No comprehensive study on cold-related mortality in central Europe has been carried out despite the fact that cold air invasions are more frequent and severe in this region than in western and southern Europe.

Methods: Cold spells were defined as periods of days on which air temperature does not exceed -3.5 degrees C. Days on which mortality was affected by epidemics of influenza/acute respiratory infections were identified and omitted from the analysis. Excess cardiovascular mortality was determined after the long-term changes and the seasonal cycle in mortality had been removed. Excess mortality during and after cold spells was examined in individual age groups and genders.

Results: Cold spells were associated with positive mean excess cardiovascular mortality in all age groups (25-59, 60-69, 70-79 and 80+ years) and in both men and women. The relative mortality effects were most pronounced and most direct in middle-aged men (25-59 years), which contrasts with majority of studies on cold-related mortality in other regions. The estimated excess mortality during the severe cold spells in January 1987 (+274 cardiovascular deaths) is comparable to that attributed to the most severe heat wave in this region in 1994.

Conclusion: The results show that cold stress has a considerable impact on mortality in central Europe, representing a public health threat of an importance similar to heat waves. The elevated mortality risks in men aged 25-59 years may be related to occupational exposure of large numbers of men working outdoors in winter. Early warnings and preventive measures based on weather forecast and targeted on the susceptible parts of the population may help mitigate the effects of cold spells and save lives.
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http://dx.doi.org/10.1186/1471-2458-9-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2632656PMC
January 2009

[Has the epidemiology of hepatitis C virus infections changed?].

Klin Mikrobiol Infekc Lek 2005 Apr;11(2):62-6

Department Of Internal Medicine, Faculty Hospital Královské Prague, Czech Republic.

Unlabelled: Chronic hepatitis C is a global health problem. The virus of hepatitis C (HCV) was discovered 15 years ago. According to the Centre for Disease Control in Antlanta the epidemiology of HCV infections has changed in recent years. Simultaneously with a substantial increase in the number of infected i.v. drug addicts (from 35 % to 60 %) and in the number of sexually transmitted infections (from 7 % to 20 %), there has been a drop in the number of patients without a patent risk factor of an HCV infection (from 40 % to 10 %). Localities with a marked increase in local anti-HCV prevalence, significantly higher than the prevalence in blood donors, were identified in Italy, China and Japan. The most probable source of infection in these localities seem to be inadequately sterilized glass injection syringes and needles, which were in use until about 1975. Since adulthood anti-HCV reactivity rises almost linearly with the patients' age: in the group of patients aged 60-69 years it can be as high as 30-40 %. This is usually explained by the use, in previous times, of inadequately sterilized glass syringes and injection needles in i.v. treatment and i.v. blood sampling, by hospital stays exceeding seven days and surgery. The remaining 10 % of as yet unexplained risk factors of HCV infections are most probably the consequence of low socio-economic standards.

Keywords: chronic hepatitis C, epidemiology, risk factors.
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April 2005