Impact of hepatitis B vaccine in Tunisia 20 years after its introduction

Résumé fourni par la source

Abstract Introduction Vaccination against hepatitis B represents the most effective preventive measure to reduce the global impact of this infection. In Tunisia hepatitis B vaccination was introduced for health professionals in 1992 and for the general population in 1995. The objectives of this study were to evaluate the impact of vaccination twenty years after its introduction. Methods It was a descriptive study of data provided by the national survey of prevalence of Hepatitis B in Tunisia, which was a household-based study conducted in 2015. Blood samples sent to the reference laboratory to test markers of hepatitis B virus infection. The Vaccine effectiveness rate was calculated using the following formula: VE = 1 - Odds-ratio (OR), where OR = ratio of odds of being vaccinated among subjects with positive HBsAg test results to the odds of being vaccinated among subjects with negative HBsAg test results. Results Approximately a quarter of our population reported having been vaccinated against HBV, a coverage rate of 26.9%. Among subjects above 20 years of age, this rate was 85.3%. Besides, 83.7% of vaccinated subjects had received the three required doses of the HBV vaccine. Analysis of vaccination status by great regions of the country showed that the vaccination coverage rate was higher in the southern region. Regarding HBsAg prevalence, the rate was significantly higher among unvaccinated subjects 0.3% vs 2.2% in those vaccinated (OR = 0.11 [0.07-0.18]). We found that among vaccinated subjects, the serologic response rate at vaccination was only 63.2% which represented 16.2% of the total population. The vaccine effectiveness indicated that vaccination reduced by 88.6% the risk of HBV infection. Conclusions These results demonstrate that vaccination against hepatitis B introduced in the national immunization schedule since 1995 has reduced the infection although the vaccination coverage rate remains below 90%. Key messages Importance of vaccination that reduced by 88.6% the risk of HBV infection. More effort required to raise awareness about vaccination against HBV.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.