First evaluation of completeness and sensitivity of the measles surveillance system in the Czech Republic, January 1, 2018 until June 30, 2019.

AIM: The aim of study was to evaluate completeness and estimate sensitivity of the measles surveillance using the new electronic version of the national notification system of infectious diseases (ISIN) in order to assess its performance. MATERIAL AND METHODS: The completeness of measles reporting in the ISIN for demographic characteristics (week and region of reporting, age and gender), date of onset, complications, hospitalisations, vaccination status, used laboratory methods and country of import from January 2018 to June 2019 was assessed. The register from National Reference Laboratory (NRL) and the ISIN were compared using the capture-recapture method (CRM). Cases were matched using unique personal identifier. The total number of measles cases in the population was assessed using the Chapmans formula. Sensitivity of reporting was calculated by dividing the number of reported cases by the CRM estimated true number of cases. RESULTS: In the ISIN, 765 measles cases were registered within specified time period. For many variables 100% completeness was found. The data were missing mainly for vaccination status (20%), serology results (55%) and used laboratory methods (8%). The NRL confirmed 653 patient samples in respected period. Within both registries (ISIN and NRL) the total 612 cases were matched. Estimated real number of measles cases using the CRM was 816 (95% CI: 809-823) compared to 806 reported cases. The estimated surveillance system sensitivity was 98.8%. Five percent (n = 41) of cases tested positively in the NRL were not reported to the ISIN. CONCLUSIONS: We found high level of reported measles data completeness in the ISIN for most variables. Estimated real and reported number of cases was in a good correlation and calculated sensitivity of the ISIN was on very high level. Though, the data sources used in the study were not independent on each other, therefore results may not be fully accurate. The technical changes (more mandatory fields and more logical syntax to check data) in the ISIN to improve data completeness are being recommended. Data providers should report all measles cases to the ISIN with maximum precision in entering individual variables and investigating laboratories should send samples for confirmation to the NRL in required cases.

Increased incidence of mumps in the Czech Republic in the years 2011 and 2012.

A nation-wide vaccination against mumps that had been launched in the Czech Republic in 1987 eliminated great outbreaks (up to 100,000 cases per year) of this disease in 1955-1988, but did not prevent small outbreaks (a few thousand cases per year) in 1995-1996, 2005-2007, and 2010-2012. The extent of these small outbreaks shows an increasing trend. The article describes mumps outbreaks in the Czech Republic in 2011 and 2012 with the aim to bring additional data contributing to the clarification of repeated outbreak triggers. In the years 2011 and 2012 there have been reported 2885 and 3902 mumps cases, respectively, in the Czech Republic. Similarly to other countries, a shift in the age-specific incidence of the disease towards higher age has been found, with the highest occurrence seen in the age group of 15-19 years. Men were slightly more affected than women. Clinical complications and vaccination status of patients were also observed.

Increase in hepatitis A cases in the Czech Republic in 2008 - an update.

In 2008, 1,616 cases of hepatitis A were reported in the Czech Republic, more than a 10-fold increase compared with the annual number of cases registered in 2003-2007. The infection was initially associated with injecting drug users, most probably by person-to-person contact or parenteral transmission, and in the second half of the year continued to spread among the general population with increased susceptibility.

Increase in hepatitis A cases in the Czech Republic in 2008--preliminary report.

The public health protection authorities in the Czech Republic report a rise in cases of viral hepatitis A (HAV) since the end of May 2008. In total, as many as 602 HAV cases have been reported in 2008 until the end of calendar week 39 (28 September).

An increase in the number of mumps cases in the Czech Republic, 2005-2006.

The Czech Republic has had a two-dose measles, mumps and rubella (MMR) vaccination programme since 1987. The last outbreak of mumps was reported in 2002, but an increase in the number of mumps cases was observed in 2005, starting in October that year. We analysed routinely collected surveillance data from 1 January 2005 to 30 June 2006 to show the magnitude of the increase and describe the most affected groups in order to better target prevention and control strategies. In the 18-month period examined, 5,998 cases of mumps were notified, with a peak incidence in May 2006. No deaths were recorded, but 21% of cases were hospitalised. Incidence was lowest in the Plzen region (1.9/100,000) and highest in Zlin (118.6/100,000). There were more male (61.8%) than female cases. The age of the cases ranged from 0 to 80 years. The highest incidence rate was observed in the age group of 15 to 19 years, in which 87% of cases had received two doses of mumps vaccine. The average age of unvaccinated cases was 22.9 years, while for cases vaccinated with two doses it was 14.5 years. Although vaccine effectiveness could not be calculated from the data available, possible reasons for highly-vaccinated cases occurring are discussed.

A study of excess mortality during influenza epidemics in the Czech Republic, 1982-2000.

Influenza related mortality rates have been established in many countries; nevertheless, studies focusing on the Central European population have been rare to date. We assess mortality attributable to influenza by comparing all cause mortality and mortality due to diseases of the circulatory system during influenza epidemic and non-epidemic periods, as defined by acute respiratory infection surveillance data. Data on total mortality, mortality due to diseases of the circulatory system and surveillance data for influenza and other respiratory infections were used in a general linear model with a logarithmic link for dependence of left censored mortality data over time, and week as a categorical factor. Results of the analysis show statistically significant (p <0.001) differences in excess mortality rates between influenza epidemic and non-epidemic periods in the Czech Republic between 1982 and 2000. We estimate that 2.17% of all cause mortality, and 2.57% of mortality due to diseases of the circulatory system throughout the study period was attributable to influenza, with an estimated annual average of 2661 and 1752 deaths respectively. The highest numbers of deaths were reported during seasons when influenza A/H3N2 was the predominant circulating strain. Improving vaccination coverage against influenza is considered to be the primary strategy for prevention of influenza associated mortality.

2001 serological survey in the Czech Republic--poliomyelitis.

Regular vaccination against poliomyelitis was started in 1960 with oral polio vaccine (OPV). Since 1992 a trivalent OPV has been administered in five doses within a nationwide vaccination campaign. The immunization coverage varies between 96.8% and 98.2% after 4 OPV doses, reaching 98.0% to 98.9% after the fifth dose. No case of indigenous poliomyelitis has been reported in the Czech Republic since the second half of 1960. In 2001, 3,230 sera were tested for the presence of antibodies against poliovirus of types 1, 2 and 3 using a virus neutralization microassay. The prevalence rates of antibodies vary between 96.0% and 100% for types 1 and 2 and between 95.1% and 100% for type 3, with the exception of the highest age group, in which the prevalence rates of antibodies against poliovirus of all three types are 92.2%.

The 2001 serological survey in the Czech Republic--viral hepatitis.

Within serological surveys 2001, prevalence of markers of hepatitis viruses A (anti-HAV), B (anti-HBc, HBsAg, anti-HBs) and for the first time also C (anti-HCV) was investigated. Sera were collected in 2001 and tested by respective kits AxSYM, Abbott. HAV: 2,623 sera were tested for the presence of anti-HAV antibodies. Comparison with serological surveys of 1984 and 1996 revealed again shifts of the age prevalence curve for anti-HAV antibodies towards higher age groups corresponding to time intervals between epidemiological surveys. High prevalence rates of anti-HAV antibodies (more than 20%) were only found for the population age groups who lived in the period of high incidence of VHA, i.e. up to 1965. The prevalence of anti-HAV antibodies increased by about 5-10% in the population under 20 years of age, the increase being significant and assumingly attributable to vaccination against VHA, and remained the same as in 1996 in the age group 20-29 years. HBV: 2,568 sera were tested for the presence of anti-HBc antibodies and 76 reactive specimens were further tested for the presence of HBsAg and anti-HBs antibodies. The prevalence of anti-HBc antibodies continuously increases with age. The total prevalence of anti-HBc antibodies calculated for the Czech population is 5.59% compared to 6.95% recorded in 1996. The calculated prevalence rate of HBsAg is 0.56% and that of anti-HBs antibodies is 3.99% for the non-vaccinee population. HCV: The prevalence rate of anti-HCV antibodies was 0.2% with 6 out of 2,950 sera testing positive. Age dependence could not be assessed because of the small number of positive persons. HCV infection is known to afflict high-risk groups, likely to escape a general serological survey, rather than the normal population.

Control of occupational hepatitis B among healthcare workers in the Czech Republic, 1982 to 1995.

Occupational hepatitis B remains a threat to healthcare workers (HCWs) worldwide, even with availability of an effective vaccine. Despite limited resources for public health, the Czech Republic instituted a mandatory vaccination program for HCWs in 1983. Annual incidence rates of acute hepatitis B were followed prospectively through 1995. Despite giving vaccine intradermally from 1983 to 1989 and intramuscularly as half dose from 1990 to 1995, rates of occupational hepatitis B decreased dramatically, from 177 cases per 100,000 workers in 1982 (before program initiated) to 17 cases per 100,000 in 1995. Among high-risk workers, the effect was even more dramatic (from 587 to 23 per 100,000). We conclude that strong public-health leadership led to control of occupational hepatitis B among HCWs in the Czech Republic, despite limited resources that precluded administering full-dose intramuscular vaccine for much of the program. Application of a similar program should be considered for other countries in regions that currently do not have a hepatitis B vaccination program.