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[Immunity against hepatitis A in younger age groups and the basis for an immunization program]
D Puntarić1, I Vodopija, Z Baklaić
1Zavod za javno zdravstvo Zupanije grada Zagreba.
Insights
Hepatitis A virus (HAV) immunity was 18.7% in children under 15 in Ivanić-Grad. The study suggests including hepatitis A vaccination in community programs, targeting children at age five.
Area of Science:
- Epidemiology
- Virology
- Immunology
Context:
- A study in Ivanić-Grad, Croatia, assessed naturally acquired immunity to Hepatitis A Virus (HAV) in 305 children up to 15 years old in September 1989.
- The overall prevalence of anti-HAV antibodies was 18.7%, with variations across age groups.
- Infection spread was predominantly by contact, indicating socioeconomic factors influenced transmission.
Purpose:
- To determine the prevalence of naturally acquired immunity to Hepatitis A Virus (HAV) in children.
- To analyze the age-specific prevalence of HAV infection.
- To provide data supporting the inclusion of HAV vaccination in public health initiatives.
Summary:
- Naturally acquired immunity to HAV in children aged up to 15 years in Ivanić-Grad was 18.7%.
- Prevalence increased with age, peaking in older children (14-15 years at 29.0%), with a notable peak in first-graders.
- A low prevalence (approx. 6.0%) was observed in children up to five years old.
Impact:
- The findings indicate a higher prevalence of HAV infection compared to developed countries.
- The study supports the recommendation for community-wide Hepatitis A vaccination, particularly targeting five-year-olds.
- This research contributes to understanding HAV epidemiology and informs public health vaccination strategies.
Abstract:
The naturally acquired immunity to hepatitis A virus (HAV) in a sample of 305 children, aged up to 15 years, in the municipality of Ivanić-Grad amounted to 18.7%. The study was conducted in September 1989. Of those 305 children, 16.8% of the boys and 20.7% of the girls were positive. No statistically significant difference was observed with regard to sex (p < 0.01) (chi 2 = 1.4). Of the children aged up to two years, 47.4% were exposed to the hepatitis A virus. Seropositive for anti-HAV were 8.3% in the group from 2-3 years of age, 6.4% in those aged from 4-5 years, 15.9% in the group from 6-7 years of age, 6.8% in those aged from 8-9 years, 20.0% in the group from 10-11 years of age, 27.8% in those aged from 12-13 years, and 29.0% in the group from 14-15 years of age. The spread of the infection by contact was predominant, reflecting the socioeconomic standards of the studied community (p < 0.01) (chi 2 = 29.5). A relatively high prevalence of hepatitis A infection compared to that of the developed countries, the first peak immunity rates in first-graders, a low number of cases among infants aged up to 5 years (approximately 6.0%), availability of commercial vaccine, speak in favour of including hepatitis A vaccination into the obligatory community-wide immunization program. It appears that the target age for HAV vaccination would be the age of five.