Control of hepatitis A by universal vaccination of children and adolescents: An achieved goal or a deferred appointment?
Section snippets
Background
Hepatitis A is an acute usually self-limiting and rarely fatal disease of the liver caused by the hepatitis A virus (HAV). Hepatitis A infection is mainly transmitted by the oro-faecal route, either through direct person-to-person contact or through contaminated food and water [1].
Hepatitis A has a worldwide distribution: in 2000, WHO estimated about 1.5 million cases of clinical hepatitis each year all over the world. The risk of developing symptomatic illness following HAV infection is
Source of data
To describe the trend of hepatitis A in Puglia, data from the regional database of routine notification of infectious diseases (from 1996 it was replaced by SIMI, Computerized System of Infectious Diseases) were used. This database was linked with a database of the Italian surveillance system of acute viral hepatitis (SEIEVA). Starting from January 2008, an active surveillance system was implemented at the Regional Observatory for Epidemiology: every week an operator calls the Infectious
Temporal trends
Between 1989 and 2008, the highest number of cases/year (5395) was reported in 1996, and the lowest in 2006 (29 cases, incidence rate: 0.7 × 100,000). The most important incidence rate (130 × 100,000) was reported during the biennium 1996–1997. Since 1999, the epidemic curve has decreased and changed its usual yearly structure that typically presented two peaks, one after the Christmas holidays and the second in summer. This incidence rates was observed in all age groups, without any differences
Discussion and conclusions
The role of the basic reproductive number R0 and the effective reproductive number Re in the evaluation of vaccination coverage is well known to epidemiologists in modelling the spread of directed transmitted disease. Their use in analysis of the spread of diseases simultaneously transmitted by direct and indirect contacts results more complex [19], [23].
The value of R0 = 2.01 estimated for hepatitis A in Puglia in 1996, according to the formula proposed by Ajelli et al., describes the large
Acknowledgments
The authors very much thank Giovanni Caputi and Vanessa Cozza for their important support in data collection.
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2017, VaccineCitation Excerpt :In most Western European countries hepatitis A incidence has also declined to below 1.0 per 100,000, in the context of immunisation programs targeting only individuals at high risk [43]. Universal routine vaccination of children has been associated with increased age of infection, and hence risk of more severe disease [44,45]. In the context of the targeted Australian immunisation program we found no change in the median age of notified and hospitalised cases between pre- and post-vaccine periods.
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2013, International Journal of Food MicrobiologyCitation Excerpt :It would be useful to evaluate the drastic reduction in the incidence of hepatitis A related to the safety of shellfish farming in Puglia in the last 20 years. Martinelli et al. (2010) showed that the universal routine vaccination against hepatitis A, introduced in Puglia for the first time in Italy in 1998 and aimed to all children 15–18 months of age and to 12-year-olds, represents a milestone in the containment of the direct transmission of the disease. A model proposed by Ajelli et al. (2008) suggested that vaccination is effective since the reduction of circulation among individuals also reduces circulation in seafood.
Spatiotemporal dynamics of viral hepatitis A in Italy
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These authors contributed equally to this study.