24 may 2024
The GlaxoSmithKline supported non-interventional seroepidemiological study “Immunological and epidemiological effectiveness of single-dose vaccination against hepatitis A in endemic region (Tyva Republic, Russian Federation) after 9 to 11 years after its implementation” has been completed.
The aim of this prospective non-interventional observational single-center study was to determine the immunological and epidemiological effectiveness of single-dose vaccination against hepatitis A 9 to 11 years after its implementation. The anti-HAV IgG antibodies were determined in two independent cohorts of children who were vaccinated with a single dose of monovalent pediatric inactivated vaccine (HAVRIX®️ 720 EU) in Tyva in 2012 and recruited 9 years (Year 9 Cohort) and 11 years (Year 11 Cohort) after immunization.
The obtained results (link) indicated that the seroprotection rates defined as anti-HAV antibody concentrations ≥10 mIU/mL reached 99.4% (95% CI: 98.2-99.9% [501/504]) in Year 9 Cohort, but decreased significantly to 79.6% (95% CI: 75.8-82.9% [398/500]) in Year 11 Cohort (p <0.0001). The anti-HAV geometric mean concentrations decreased from 1446.3 mIU/mL (95% CI: 1347.1-1545.4 mIU/mL) in Year 9 Cohort to 271.2 mIU/mL (95% CI: 219.1-323.1 mIU/mL, p <0.0001) in Year 11 Cohort. HAV vaccination program resulted in zero rates of hepatitis A incidence in Tyva Republic since 2016. However, the monitoring of HAV RNA in sewage and environmental samples demonstrated the ongoing circulation of both the regional epidemic strain of HAV genotype IA and another genotype IA strain imported recently from other parts of the Russian Federation, probably due to subclinical infections in non-vaccinated children under 3 years of age.
Taken together, these data indicate the effectiveness of the single-dose HAV vaccination strategy but suggest the need to expand the vaccination program to include children aged 12 months and older to achieve maximum effectiveness.
31 may 2021
GlaxoSmithKline supported non-interventional sero-epidemiological study “Immunological and epidemiological effectiveness of single-dose vaccination against hepatitis A in endemic region (Tyva Republic, Russian Federation) after 9 to 11 years after its implementation” Protocol number EPI-HAV-012. Study number 18/21 dated 27.05.2021.
Mechnikov Institute of Vaccines and Sera, with financial support from GlaxoSmithKline, conducts a sero-epidemiological study in the Republic of Tyva aimed at studying the immunological and epidemiological effectiveness of a single-dose vaccination against hepatitis A started in the region in 2012. The study will provide data on the immunity to hepatitis A virus in children vaccinated with a single dose of hepatitis A vaccine 9 -11 years ago. Also, the reported morbidity rates and the frequency of detection of hepatitis A virus in sewage after the introduction of a single-dose pediatric mass vaccination against hepatitis A into the regional Immunization Schedule will be analyzed.