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Impact of routine infant and adolescent hepatitis B vaccination in Tuscany, Central Italy
P Bonanni1, R Colombai, R Gasparini
1Public Health and Epidemiology Department, University of Florence, Italy. bonanni@dsp.igiene.unifi.it
Insights
Hepatitis B vaccination coverage in Italy is excellent, with 95% of infants and adolescents receiving three doses. This high vaccination rate has led to a significant decline in hepatitis B cases and may lead to elimination of the virus.
Area of Science:
- Immunology
- Public Health
- Epidemiology
Background:
- Routine infant and adolescent immunization against hepatitis B was implemented in Italy in 1991.
- This study evaluates the impact of this mandatory vaccination program.
Purpose of the Study:
- To assess hepatitis B vaccine coverage rates in infants and adolescents.
- To evaluate seroconversion rates and antibody titers post-vaccination.
- To analyze trends in acute hepatitis B cases.
Main Methods:
- A 6-year study (1992-1997) in Tuscany matched birth and immunization records.
- Sera from vaccinated adolescents and children were tested for anti-hepatitis B surface antigen antibody (anti-HBs) titers.
- Incidence of acute hepatitis B was calculated from regional infectious disease statistics.
Main Results:
- Vaccine coverage reached 95% for both infants and adolescents.
- 98% of adolescent vaccinees achieved seroconversion, with 87% of children showing protective anti-HBs titers.
- A 49% decrease in acute hepatitis B cases was observed in 15- to 24-year-olds; no cases occurred in vaccinated adolescents.
Conclusions:
- Mandatory hepatitis B immunization in Italy demonstrates excellent coverage.
- Sustained vaccination efforts at current levels could lead to hepatitis B virus elimination within decades.
Background:
In Italy routine infant and adolescent immunization against hepatitis B was introduced in 1991.
Objective:
Evaluation of (1) coverage with three doses of hepatitis B vaccine in infants and adolescents; (2) seroconversion to anti-hepatitis B surface antigen antibody (anti-HBs) in adolescents receiving three doses of vaccine; (3) concordance of coverage rates in infants with prevalence of neutralizing antibodies in sera from anonymous children; (4) trend of notified cases of acute hepatitis B.
Methods:
A sample of infants and adolescents living in Tuscany was studied during 6 years (1992 through 1997) by matching birth records and immunization certificates. Sera from 139 adolescents who completed the vaccination course and from 159 anonymous children belonging to immunized cohorts (1 to 5 years) were tested with a quantitative anti-HBs assay. Incidence of acute hepatitis B by age was calculated from regional statistics on notified infectious diseases between 1992 and 1996.
Results:
Overall 10,606/11,164 (95%) infants and 10,599/11,100 (95%) adolescents received 3 doses of vaccine. Seroconversion to anti-HBs was detected in 98% of adolescent vaccinees. Anti-HBs titers > or =10 IU/l were detected in 87% of children. A 49% decline of acute hepatitis B cases was registered between 1992 and 1996 in 15- to 24-year-olds living in Tuscany. No case occurred in vaccinated adolescents.
Conclusions:
Coverage against hepatitis B is excellent in cohorts subject to mandatory immunization. If efforts to vaccinate are maintained at these levels, elimination of hepatitis B virus transmission could occur within few decades in Italy.