Low dose hepatitis B vaccination in children.

Area of Science:

• Pediatrics
• Immunology
• Vaccinology

Background:

• Hepatitis B virus (HBV) infection poses a significant global health risk, particularly in children.
• Effective vaccination strategies are crucial for preventing HBV transmission and long-term sequelae.
• Assessing vaccine efficacy across different age groups and administration routes is essential for public health initiatives.

Purpose of the Study:

• To evaluate the immunogenicity and efficacy of a two-microgram hepatitis B vaccine dose administered intradermally (ID) or intramuscularly (IM) in children.
• To determine the optimal vaccination schedule and dosage for mass immunization programs in a high-risk mobile community.
• To assess the impact of prior hepatitis B virus (HBV) exposure on vaccine response.

Main Methods:

• 169 HBsAg-negative children received three doses of hepatitis B vaccine (2 or 4 micrograms) at monthly intervals via ID or IM routes.
• Children were tested for HBsAg, anti-HBs, and anti-HBc after the second and third vaccine doses.
• Serological markers were analyzed to determine seroconversion rates, geometric mean titres (GMT), and evidence of prior infection.

Main Results:

• Overall, 74% and 71% seroconversion rates for anti-HBs were observed after two doses with 2 mcg and 4 mcg, respectively.
• Prior HBV infection (anti-HBc positive) was identified in 4% of 3-5 year olds and 26% of 9-12 year olds.
• After three doses, 91% of previously susceptible older children achieved acceptable anti-HBs GMTs, and all anti-HBc positive children sero-converted.

Conclusions:

• A 2 mcg dose of hepatitis B vaccine administered intradermally at monthly intervals is effective for mass vaccination.
• This regimen provides over 90% seroconversion in susceptible children with low cost and minimal side effects.
• The findings support the use of this vaccination strategy in high-risk pediatric populations to control hepatitis B transmission.