Immunogenicity of single dose live attenuated hepatitis a vaccine

Area of Science:

• Immunology and Vaccinology
• Pediatric Infectious Diseases
• Public Health Research

Background:

• Hepatitis A remains a significant public health concern, particularly in developing countries.
• Live attenuated vaccines offer a promising strategy for long-term hepatitis A prevention.
• Understanding the durability of immune response in pediatric populations is crucial for vaccination programs.

Purpose of the Study:

• To assess the long-term immunogenicity of a single dose of live attenuated H2 strain hepatitis A vaccine.
• To evaluate seroprotective antibody levels in healthy Indian children 30 months post-vaccination.
• To monitor for any hepatitis-like illnesses in vaccinated subjects.

Main Methods:

• A longitudinal study involving 131 healthy Indian children previously vaccinated with a single dose of H2 strain hepatitis A vaccine.
• Anti-HAV antibody levels were measured 30 months after vaccination.
• Seroprotection defined as antibody levels >20 mIU/mL; Geometric Mean Titer (GMT) calculated.

Main Results:

• 87.8% of subjects demonstrated seroprotective antibody levels (>20 mIU/mL) at 30 months post-vaccination.
• The overall Geometric Mean Titer (GMT) was 92.02 mIU/mL, indicating a robust immune response.
• No instances of hepatitis-like illness were reported in any vaccinated child during the follow-up period.

Conclusions:

• A single dose of the live attenuated H2 strain hepatitis A vaccine provides sustained seroprotection in Indian children for at least 30 months.
• The vaccine is well-tolerated and effective in preventing hepatitis A infection in this cohort.
• These findings support the use of this vaccine for long-term hepatitis A prevention in pediatric populations.