Human enterovirus surveillance in the Slovak Republic from 2001 to 2011.

We report the outcome of an 11-year programme monitoring sewage water and acute flaccid paralysis (AFP) cases as part of the World Health Organization (WHO) strategy for polio eradication in the Slovak Republic (SR). Polioviruses (PV) and non-polio enteroviruses (NPEV), prior to and after the change in polio vaccination strategy, were detected. Sewage treatment plant samples from 48 localities spread over the Western, Central and Eastern regions and clinical material from AFP cases were examined. The WHO standard procedures were followed with regard to virus isolation and identification. There were 538 commonly detected human enteroviruses (HEVs) including 213 (40%) coxsackie B viruses (CBV), 200 (37%) echoviruses and 113 (21%) Sabin-like PVs (PV1, 2, 3) including vaccine-derived poliovirus (VDPV) isolates. The percentage of PV isolates fell from 66% to 30% during 2001-2005 and thereafter fell to zero. CBV5, CBV2 and echovirus 3 were the NPEVs endemic during the study period.

Comparative hepatitis A seroepidemiology in 10 European countries.

The WHO recommends hepatitis A virus (HAV) immunization according to level of transmission and disease burden. We aimed to identify susceptible age groups by standardized serosurveys to inform HAV vaccination policy in participating countries: Belgium, Czech Republic, England, Finland, Germany, Italy, Lithuania, Malta, Romania, and Slovakia. Each country tested national serum banks (n = 1854-6748), collected during 1996-2004, for anti-HAV antibodies. Local laboratory results were standardized to common units. Forty-one per cent of those aged <30 years and 6% of those aged ≥30 years were susceptible to HAV in Romania; compared to 70-94% and 26-71%, respectively, elsewhere. Romania reported high HAV incidence in children and young adults. Other countries reported HAV disease primarily in older risk groups. The results suggest low level of HAV transmission in most of Europe. Romania, however, appeared as an area with intermediate transmission. Vaccination of risk groups in countries with high susceptibility of young and middle-aged adults needs to be continued.

[Isolation of highly divergent vaccine strains of polioviruses in Slovakia]. / Izolácia vysoko divergentného vakcinálneho poliovírusu na Slovensku.

April 2003 was the first time in Slovakia, when the vaccine derived poliovirus Type 2 was isolated from waste water sampled from the waste water disposal plant in Vrakun, which collects most waste from Bratislava. The examination in the Regional reference laboratory in Helsinki revealed an almost 15% divergence from the vaccine strain and genetic identity with the Sabine vaccine strain was only 86.6%. Various cases of paralytic poliomyelitis have been published in world literature, caused by mutants = vaccine derived polioviruses (VDPV). Sporadic diseases were described not only in persons who excreted genetically modified vaccine strains, but even examples of epidemic occurrence connected with circulation and transfer of VDPV in non-vaccinated or insufficiently vaccinated population. Epidemiologist of the State Faculty Public Health Institute of Bratislava, the capital of Slovakia immediately accepted measures to strengthen surveillance of poliomyelitis at all levels in order to minimize the risk for the origin of paralytic disease in the population. The world-wide activities aimed at eradication of poliomyelitis may eliminate the wild virus from human community as well as from the environment. It will be difficult to eradicate poliomyelitis completely before the potentially infectious oral vaccine is substituted with inactivated vaccine.

A comparison of hepatitis B seroepidemiology in ten European countries.

To inform current and future vaccination strategies, we describe the seroepidemiology of hepatitis B virus (HBV) infection in ten representative European countries using standardized serology that allowed international comparisons. Between 1996 and 2003, national serum banks were compiled by collecting residual sera or by community sampling; sera were then tested by each country using its preferred enzyme immunoassays and testing algorithm, and assay results were standardized. Information on current and past HBV vaccination programmes in each country was also collected. Of the ten countries, six reported low levels (<3%) of antibodies against HBV core antigen (anti-HBc). Of the eight countries testing for HBV surface antigen (HBsAg), the highest prevalence was reported in Romania (5.6%) and in the remaining seven countries prevalence was <1%. Universal HBV vaccination programmes had been established in seven countries as recommended by the World Health Organization, but the seroprevalence of antibodies against HBsAg (anti-HBs) was lower than the reported vaccine coverage in three countries. Regular serological surveys to ascertain HBV status within a population, such as reported here, provide important data to assess the need for and to evaluate universal HBV vaccination programmes.

The European Sero-Epidemiology Network 2 (ESEN2): standardization of assay results for hepatitis A virus (HAV) to enable comparisons of seroprevalence data across 15 countries.

The European Sero-Epidemiology Network 2 (ESEN2) aimed to compare serological results of vaccine-preventable diseases across Europe. To ensure direct inter-country comparability of hepatitis A virus antibody (anti-HAV) measurements, a standardization panel of 150 sera was developed by a designated reference laboratory and tested by participating national laboratories using assays of choice; each country's results were subsequently regressed against those of the reference laboratory. Quantitatively, the assays were generally highly correlated (R2>0.90). Nevertheless, qualitative comparisons indicated that results obtained with different assays may differ despite the usage of well-established international and local standards. To a great extent standardization successfully alleviated such differences. The generated standardization equations will be used to convert national serological results into common units to enable direct international comparisons of HAV seroprevalence data. The results of this study are expected to contribute to the evaluation and potential improvement of the currently employed immunization strategies for hepatitis in Europe.

The European Sero-Epidemiology Network 2: standardization of assay results for hepatitis B virus.

The aim of the European Sero-Epidemiology Network 2 was to coordinate and standardize the serological surveillance of vaccine-preventable diseases in Europe. In this study, the standardization of hepatitis B virus (HBV) results is described. The 15 participating national laboratories tested a unique panel of 172 sera established by the Greek reference centre for HBV surface antigen (HBsAg), antibodies to HBsAg (anti-HBs) and/or to the HBV core antigen (anti-HBc) by assay methods of their choice. Country-specific quantitative measurements for anti-HBs and anti-HBc were transformed into common units using standardization equations derived by regressing each country's panel results against the reference centre's results, thus adjusting for interassay and interlaboratory variability. For HBsAg, a qualitative analysis (positive/negative) showed at least 99% agreement with the reference laboratory for all countries. By combining these standardized and qualitative results for the markers mentioned earlier, it was possible to achieve comparable estimates of the proportion of the population susceptible to HBV, vaccinated against HBV, with a past HBV infection, and with a current infection or chronic carrier state. Standardization is a very important tool that allows for international serological comparisons to assess the current vaccination policies and the progress of HBV control in Europe.