Epidemiological impact of hepatitis B vaccination in Monastir Tunisia (2000-17)

Background: In 2016, the first global health sector strategy on viral hepatitis was endorsed with the goal of eliminating viral hepatitis as a public health threat by 2030. In Tunisia, effective vaccines for hepatitis B (HBV) have been added to the expanded programme of immunization (EPI) since July 1995 for new borns. We expected to have a decreasing trend in the prevalence rate of reported HBV. Our study aimed to address the epidemiological profile of HBV, to assess trends by age and gender in Monastir governorate over a period of 18 years according to immunization status and to estimate the burden (years lived with disability YLDs) of this pathology. Methods: We performed a descriptive cross sectional study of declared HBV from January 1, 2000 to December 31, 2017 defined as having positive serologic markers for HBs Ag. All declared patients were residents of Monastirs Governorate. EPI included two periods, the first between 1995 and 2006 following a three-dose schedule (3, 4, 9 months). The second PI cohort after 2006 following a three-dose schedule (0, 2, 6 months). Results: During 18 years, 1526 cases of HBV were declared in Monastir with a mean of 85 cases per year. We estimated a mean of 1699 declared cases per year of HBV in Tunisia. CPR was 16.85/100,000 inh being the higher in age group of 20-39 years and in men .ASR was 15.99/100,000 inh, being 35.5 in men and 8.69 in women. During the study period, declared cases among presumed immunized (PI) person against HBV were 32(2.0%). Among PI cases, 29 were from the first period and 3 were from the second. We established a negative trend over 18 years of hepatitis B. The age group of 20 to 39 was the most common with a sharply decline. Presumed not immunized (PNI) HBV cases are decreasing by years with a prediction of 35 cases in 2024. Reported HBV contributed to 1.26 YLDs per 100,000 inh. The highest rate of YLDs occurred at the age 20-39 (2.73 YLDs per 100,000 inh). During 18 years, YLDs were 114.45 in Monastir with a mean of 2293.65 YLDs of HBV in Tunisia. Conclusion, this study showed a law prevalence rate and a decreasing trend of HBV during 18 years showing an efficacy of immunization and confirming that the universal hepatitis B vaccination in Tunisia has resulted in progress towards the prevention and control of hepatitis B infection. These findings should be demonstrated in other Tunisian regions with a standardized serological profile.