An assessment of the effect of hepatitis B vaccine in decreasing the amount of hepatitis B disease in Italy

July 26, 2008

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An assessment of the effect of hepatitis B vaccine in decreasing the amount of

hepatitis B disease in Italy.

Hepatitis B (HBV) infection is an important cause of morbidity and mortality and

it is associated to a higher risk of chronic evolution in infected children. In

Italy the anti-HBV vaccination was introduced in 1991 for newborn and twelve

years old children.

Our study aims to evaluate time trends of HBV incidence rates in order to

provide an assessment of compulsory vaccination health impact.MethodData

concerning HBV incidence rates coming from Acute Viral Hepatitis Integrated

Epidemiological System (SEIEVA) were collected from 1985 to 2006. SEIEVA is the

Italian surveillance national system that registers acute hepatitis cases.

Time trends were analysed by joinpoint regression using Joinpoint Regression

Program 3.3.1 according to Kim's method. A joinpoint represents the time point

when a significant trend change is detected.

Time changes are expressed in terms of the Expected Annual Percent Change (EAPC)

with 95% confidence interval (95% CI).

Results: The joinpoint analysis showed statistically significant decreasing

trends in all age groups. For the age group 0-14 EAPC was -39.0 (95% CI: -59.3;

-8.4), in the period up to 1987, and -12.6 (95% CI: -16.0; -9.2) thereafter.

EAPCs were -17.9 (95% CI: -18.7; -17.1) and -6.7 (95% CI: -8.0; -5.4) for 15-24

and greater than or equal to 25 age groups, respectively. Nevertheless no

joinpoints were found for age groups 15-24 and greater than or equal to 25,

whereas a joinpoint at year 1987, before compulsory vaccination, was highlighted

in 0-14 age group.

No joinpoint was observed after 1991.DiscussionOur results suggest that the

introduction of compulsory vaccination could have contribute partly in

decreasing HBV incidence rates. Compulsory vaccination health impact should be

better investigated in future studies to evaluate the need for changes in

current vaccination strategy.

Author: Giuseppe La Torre, Nicola Nicolotti, Chiara de Waure, Giacomina

Chiaradia, Lucia Specchia, Alice Mannocci and Walter Ricciardi

Credits/Source: Virology Journal 2008, 5:84

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July 26, 2008