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Open Access Research article

Hepatitis A in Puglia (South Italy) after 10 years of universal vaccination: need for strict monitoring and catch-up vaccination

Maria Chironna13*, Rosa Prato23, Anna Sallustio1, Domenico Martinelli23, Silvio Tafuri13, Michele Quarto13 and Cinzia Germinario13

Author Affiliations

1 Department of Biomedical Sciences and Human Oncology - Section of Hygiene, University of Bari, Piazza G. Cesare 11, Bari, 70124, Italy

2 Department of Medical and Occupational Science - Section of Hygiene, University of Foggia, Foggia, 71100, Italy

3 Puglia Regional Epidemiological Observatory, Bari, Italy

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BMC Infectious Diseases 2012, 12:271  doi:10.1186/1471-2334-12-271

Published: 25 October 2012

Abstract

Background

Raw seafood consumption was identified as the major risk factor for hepatitis A during the large epidemic of 1996 and 1997 in Puglia (South Italy). In Puglia, vaccination for toddlers and preadolescents has been recommended since 1998.

The aim of the study was to evaluate the incidence, seroprevalence, molecular epidemiology, and environmental circulation of hepatitis A virus (HAV) in Puglia more than ten years after the introduction of anti-HAV vaccination in the regional immunization program.

Methods

Data on the incidence of acute hepatitis A in Puglia were analyzed. Characteristics and risk factors of 97 acute hepatitis A cases occurring in 2008–2009 were analyzed. Serum samples from 868 individuals aged 0 to 40 years were tested for anti-HAV antibodies. Fecal samples from 49 hepatitis A cases were analyzed by sequence analysis in the VP1/P2A region. In 2008, 203 mussel samples and 202 water samples from artesian wells were tested for HAV-RNA.

Results

Between 1998 and 2009, the incidence of acute hepatitis A declined from 14.8 to 0.8 per 100,000. The most frequent risk factors reported by cases in 2008–2009 were shellfish consumption (85%) and travel outside of Puglia or Italy (26%). Seroepidemiologic survey revealed high susceptibility to HAV in children and adults up to age 30 (65%-70%). None of the mussel or water samples were HAV-positive. Phylogenetic analysis revealed co-circulation of subtypes IA (74%) and IB (26%) and clustering of strains with strains from Germany and France, and those previously circulating in Puglia.

Conclusion

Vaccination and improved sanitation reduced the incidence of hepatitis A. Strict monitoring and improved vaccination coverage are needed to prevent disease resurgence.

Keywords:
Environment; Hepatitis A vaccination coverage; Phylogenetic analysis of HAV; Puglia; Seroepidemiology