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Evaluation of a low dose of hepatitis B vaccine given within a childhood immunisation programme in Singapore
Insights
A low dose (5 micrograms) of hepatitis B (HB) vaccine is as effective as the standard dose for newborns. This vaccination schedule can be integrated into existing childhood immunization programs to prevent HB virus infection.
Area of Science:
- Pediatrics
- Immunology
- Public Health
Background:
- Hepatitis B (HB) virus infection poses a significant risk to newborns, particularly those born to infected mothers.
- Current vaccination protocols involve higher doses, and integrating a lower dose into existing infant immunization schedules requires feasibility assessment.
- Assessing the immunogenicity and efficacy of a reduced-dose hepatitis B vaccine is crucial for optimizing infant protection strategies.
Purpose of the Study:
- To evaluate the feasibility and immunogenicity of a low-dose (5 micrograms) hepatitis B vaccine administered at birth, 1 month, and 2 months.
- To compare the efficacy of the 5-microgram dose against the standard 10-microgram dose in preventing hepatitis B infection in newborns.
- To determine the effectiveness of this vaccination schedule within an established primary childhood immunization program.
Main Methods:
- A randomized study involving 662 healthy Singaporean newborns from mothers with varying hepatitis B surface antigen (HBsAg) statuses.
- Infants received either a 5-microgram or 10-microgram dose of the hepatitis B vaccine (B-Hepavac) at specified intervals.
- Specific groups received hepatitis B immunoglobulin (HBIg) alongside the vaccine, and outcomes were assessed based on seroconversion and HBsAg status.
Main Results:
- The 5-microgram dose demonstrated immunogenicity comparable to the 10-microgram dose across all studied neonatal groups.
- Anti-HBsAg seroconversion rates at one year were high (95.8% for 5 mcg vs. 91.9% for 10 mcg) in infants of HBsAg-negative mothers.
- Passive plus active immunization was 100% protective in HBsAg-negative neonates born to HBsAg-positive/HBeAg-positive mothers; efficacy was 88% in HBsAg-positive neonates.
Conclusions:
- The low-dose (5 micrograms) hepatitis B vaccine is as immunogenic and effective as the standard dose in newborns.
- Integrating this reduced-dose vaccination into existing childhood immunization programs is feasible and effective in preventing hepatitis B infection and chronic carriage.
- This approach offers a viable strategy for protecting infants at risk of hepatitis B virus exposure.
Abstract:
The feasibility of introducing low dose (5 micrograms) hepatitis B (HB) virus vaccination at birth and again 1 and 2 months later as part of an existing primary immunisation programme of childhood, was assessed in 662 healthy newborn Singapore children. The vaccine (B-Hepavac, Menck, Sharp and Dohme) was given to three neonatal groups: those born to HB surface antigen (sAg)-negative mothers, HBsAg-positive/HBeAg-positive mothers and HBsAg-positive/HBeAg-negative mothers. A dose of 5 micrograms was compared in a randomised study with the more usual 10 micrograms dose given at the same intervals. Neonates born to HBsAg-positive/HBeAg-positive mothers were also given hepatitis B immunoglobulin (HBIg) at birth. The 5 microgram dose of vaccine was as immunogenic as the 10 microgram dose in all three groups of children studied. At 1 year, anti-HBsAg seroconversion among infants of antigen-negative mothers was 95.8% for the 5 microgram dose and 91.9% for the 10 microgram dose. Suppression of anti-HBsAg formation was not seen even when maternal anti-HBsAg was present or HBIg given. Among infants born to HBsAg-positive/HBeAg-positive mothers, passive plus active immunisation was 100% protective at doses of 5 micrograms and 10 micrograms vaccine in the newborns who were HBsAg-negative at 24 h. Seroconversion after both the 5 and 10 microgram doses of vaccine was reduced, however, to 88% in each group of infants who were already HBsAg-positive at 24 h of age. Overall, passive plus active immunisation as well as HB vaccine alone (5 micrograms dose), given within the existing but expanded primary immunisation programme of childhood, was effective in preventing infection and the chronic carrier state in newborns exposed to risk of HB virus infection during infancy.