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Implementing universal vaccination programmes: Bulgaria
N Gatcheva1, N Vladimirova, A Kourtchatova
1Department of Epidemiology, National Centre of Infections and Parasitic Diseases, Sofia, Bulgaria.
Insights
Universal vaccination against hepatitis B virus (HBV) in Bulgaria significantly reduced infant infections by 82%. Expanding coverage to all young children is recommended to further decrease the chronic HBV burden.
Area of Science:
- Public Health
- Epidemiology
- Immunization Programs
Background:
- Bulgaria implemented universal hepatitis B virus (HBV) vaccination for newborns in August 1991.
- This followed a three-year selective immunization program for infants born to HBsAg-positive mothers.
Purpose of the Study:
- To evaluate the impact of universal HBV vaccination on infant morbidity in Bulgaria.
- To assess the trend of hepatitis B incidence post-vaccination introduction.
Main Methods:
- Analysis of hepatitis B morbidity data among infants from 1989 to 1992.
- Calculation of incidence rates and percentage decrease compared to the pre-immunization period.
Main Results:
- Vaccination coverage reached 71.3% in 1992.
- Infant hepatitis B morbidity showed a continuous downward trend, reaching 0.3 cases per 100,000 in 1992.
- This represents an 82% decrease in incidence compared to the pre-vaccination era.
Conclusions:
- Universal HBV vaccination has been highly effective in reducing infant hepatitis B infections in Bulgaria.
- Expanding vaccination to all children up to 6 years is proposed to further mitigate the long-term burden of chronic HBV infection.
Abstract:
Universal vaccination against hepatitis B virus (HBV) was introduced for all newborns in Bulgaria in August 1991, after a three-year selective immunization of babies born to HBsAg-positive mothers. In 1992, a coverage level of 71.3% was achieved. Since 1989, hepatitis B morbidity among infants shows a continuing downward trend with the lowest annual incidence rate, 0.3 cases per 100,000, in 1992. This represents an 82% decrease compared to the preimmunization period. As strong epidemiological evidence exists that an early age of infection substantially increases the overall burden of chronic HBV infection, future expansion of vaccination coverage to include all children up to 6 years of age was considered an appropriate alternative to the existing policies.