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Integration of hepatitis B vaccination into rural African primary health care programmes
B D Schoub1, S Johnson, J M McAnerney
1National Institute for Virology, Sandringham, South Africa.
Insights
Hepatitis B vaccine integration into routine immunization programs in rural Africa faced challenges, but the vaccine proved effective even with varied dosing intervals. A tetravalent vaccine combining hepatitis B with DTP is suggested for better integration.
Area of Science:
- Public Health
- Vaccinology
- Infectious Disease Epidemiology
Background:
- The Expanded Programme on Immunisation (EPI) aims to provide essential vaccines globally.
- Hepatitis B virus (HBV) infection is a significant global health concern, particularly in developing regions.
- Integrating new vaccines into existing EPI schedules presents logistical and efficacy challenges.
Purpose of the Study:
- To assess the effectiveness of the hepatitis B vaccine when added to the routine EPI in rural African settings.
- To compare different vaccination schedules for the hepatitis B vaccine under field conditions.
- To evaluate the serological response and coverage rates of the hepatitis B vaccine within the EPI.
Main Methods:
- A cohort of infants in Venda, South Africa, was enrolled in the study.
- Two vaccination schedules were compared: an early schedule (birth, 3, 6 months) and a later schedule (3, 4.5, 6 months).
- Vaccine coverage, antibody prevalence against hepatitis B surface antigen (HBsAg), and antibodies against hepatitis B core antigen (HBcAg) were measured.
Main Results:
- Hepatitis B vaccine coverage significantly declined after the first dose (99% to 39% by the third dose), unlike polio vaccine coverage.
- Despite coverage challenges, serological evaluation showed high vaccine efficacy, with only 3.5% failing to develop antibodies.
- Most infants (93.4%) received doses outside the planned schedules, yet seroconversion rates were similar across scheduled and unscheduled groups.
Conclusions:
- Integrating hepatitis B vaccine into the current EPI in rural Africa is difficult due to coverage issues.
- The hepatitis B vaccine demonstrated effectiveness even with extended dosing intervals.
- Combining hepatitis B vaccine with diphtheria, tetanus, and pertussis (DTP) into a tetravalent vaccine is proposed for improved integration in resource-limited settings.
Objective:
To determine the efficacy of hepatitis B vaccine when added to the routine expanded programme on immunisation under field conditions in rural Africa.
Design:
Infants were immunised according to two schedules--an early schedule at birth, 3 months, and 6 months and a later schedule to correspond with routine vaccination in the expanded programme on immunisation at 3 months, 4 1/2 months, and 6 months.
Setting:
Venda, northern Transvaal, South Africa, a self governing region of 7460 square kilometers varying from rural villages to small towns.
Subjects:
The 1989 birth cohort of Venda.
Main Outcome Measures:
Coverage for hepatitis B vaccine at first, second, and third doses; serological assessment of vaccine efficacy by prevalence of antibodies to hepatitis B surface antigen in infants who had completed the three dose course of immunisation; antibodies to hepatitis B core antigen to determine if natural infection occurred.
Results:
Vaccine coverage for hepatitis B dropped sharply from 99% to 53% to 39% for the first, second, and third dose respectively. In contrast, vaccine coverage was maintained at 97-99% for the three doses of poliomyelitis vaccine. Serological evaluation of vaccine efficacy showed that only 3.5% of recipients of all three doses failed to develop antibodies to hepatitis B surface antigen. Only 6.6% of vaccine recipients were vaccinated according to either the early or later schedules whereas 93.4% received their doses of vaccine at intervals beyond the limits of either of the planned schedules. There was, however, no significant difference in seroconversion to the surface antigen between the "unscheduled" or scheduled groups of those who were vaccinated according to the early or late schedules. The pattern of prevalence of antibodies to hepatitis B core antigen, which showed a sharp fall in children aged over 7 months, suggested that the antibodies were acquired passively rather than by active infection.
Conclusions:
Supplementation of the present expanded programme on immunisation with hepatitis B vaccine in rural Africa is fraught with difficulties. However, the vaccine was effective within a fairly wide spacing of dosage. Adding hepatitis B vaccine to diphtheria, tetanus, and pertussis as a tetravalent vaccine is proposed as a means of effectively integrating it into the expanded programme on immunisation in Third World settings.