Hepatitis A seroprevalence in children and adults in Kiev City, Ukraine.

Ukraine is a zone of moderate hepatitis A endemicity. The changing epidemiology of the disease because of improved hygiene has shifted the burden of Hepatitis A to older age groups where the disease is more severe. Outbreaks have also become more common as more of the population has become susceptible to hepatitis A virus (HAV). To help guide decisions regarding use of hepatitis A vaccine in Ukraine, we examined the presence of antibody to HAV (anti-HAV) in 1001 persons aged 1 to 85 years, visiting four municipal healthcare centres in the Ukrainian capital, Kiev. Overall, the anti-HAV prevalence was 31.9%. Anti-HAV seropositivity increased with age from 9.2% among children aged 1-5 years to 81.7% among persons over 50 years, but less than 50% of subjects less than 50 years were HAV seropositive. No children under 2 years were seropositive. HAV seropositivity was twice as high in children aged 5-11 years old in the low socio-economic status group (income less than 150 US$ per family member per month) than in the middle/high group (11.1% compared to 6.3%) but this disparity disappeared by adolescence. The prevalence of anti-HAV antibodies in adults was not different with respect to district of residence within the city. Considering the proportion of HAV seronegative subjects in all age groups under 50 years, routine vaccination against HAV of children aged 1-2 years old would appear to be an effective schedule for hepatitis A prophylaxis in Kiev.

Effectiveness of universal hepatitis A immunization of children in Minsk City, Belarus: four-year follow-up.

Hepatitis A is a reportable disease in Belarus. Universal hepatitis A vaccination of children aged 6 years in Minsk City began in 2003. This analysis was conducted to evaluate the short-term impact of the program. Hepatitis A incidence data from 1954 to 2006 was compiled. Vaccination effectiveness was estimated by comparing the incidence of reported hepatitis A cases after 4 years of immunization (2006) with the incidence when the vaccination program started (2003). The vaccines used were Avaxim 160 or Avaxim 80 (95%) and Havrix 720 (5%). From 2003 through 2006, hepatitis A incidence in vaccinated children under 14 years was 20-fold lower than the incidence in unvaccinated children (0.3 cases/10000 vs 5.98/10000; odds ratio = 0.05, 95% CI: 0.012-0.202), for a vaccination effectiveness of 95%. The decreased incidence of hepatitis A in all age groups in 2006 (by 12 times in preschool children aged 1-5 years, 13 times in children aged 10-14 years and 4-6 times among adults), including those without high coverage by vaccination, suggest a herd effect. Routine vaccination also resulted in a shift of the age pattern of hepatitis A morbidity. The proportion of cases in children under 14 years decreased from 33% to 41% in 2000-2002 to 7% in 2005-2006. We conclude that introduction of universal hepatitis A vaccination in Minsk resulted in sharply reduced incidence in both vaccinated and unvaccinated children. Hepatitis A virus circulation might decrease further by beginning vaccination at a younger age.