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Epidemiology of hepatitis B infection in Finland: Implications for immunisation policy

Wednesday, 4th of January 2017 Print

Vaccine. 2017 Jan 11;35(3):412-418. doi: 10.1016/j.vaccine.2016.11.090. Epub 2016 Dec 18.

Epidemiology of hepatitis B infection in Finland: Implications for immunisation policy

Karvonen T1, Auranen K2, Kuusi M3, Leino T4.

Author information

1Department of Health Protection, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: tanja.karvonen@thl.fi.

2Department of Health Protection, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland; Department of Mathematics and Statistics, University of Turku, FI-20014, Finland. Electronic address: kari.auranen@thl.fi.

3Department of Infectious Diseases, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: markku.kuusi@thl.fi.

4Department of Health Protection, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: tuija.leino@thl.fi.

Abstract below; full text is at http://www.sciencedirect.com/science/article/pii/S0264410X1631180X

OBJECTIVES:

We describe the current epidemiology of acute and chronic hepatitis B infections in Finland. We estimate the total incidence of chronic hepatitis B following from the current incidence of acute infections and the influx of chronic carriers of hepatitis B associated with net immigration. We evaluate the incidence of hepatitis B infections preventable by a universal vaccination programme among infants.

METHODS:

We analysed hepatitis B cases reported to the National Infectious Disease Register during 2004-2012 and used pre-developed methods to adjust for acute asymptomatic infections. We estimated the projected incidence of chronic infection by applying age-specific risks of chronic infection to the estimated incidence of acute infection. We estimated the influx of chronic carriers associated with immigration by utilising data on immigration during 2004-2012 and the WHO regional estimates of carriage prevalence.

RESULTS:

The estimated incidence of acute hepatitis B infection in Finland, adjusted for asymptomatic infections, was 1.67 per 100,000 per year (95% Crl 1.43-1.94) which is 4.2-fold to the register-based incidence. The estimated lifetime risks of acute and chronic hepatitis B infections were 0.13% and 0.01%, respectively. We estimated that annually seven new chronic infections would result from infections acquired in Finland. These new chronic infections accounted for 1.2% of the total incidence of chronic infections. We estimated that eventually three chronic infections per year would be potentially preventable by a universal infant vaccination programme.

CONCLUSIONS:

Partly due to the fact that hepatitis B infections in neonates and in children are rare, a very limited number of chronic hepatitis B infections resulted from infection acquired within the country. A vast majority of chronic hepatitis B infections occurred among foreign-born persons and were therefore not preventable by a universal infant immunisation programme in Finland. Even with a targeted immunisation programme, the incidence of hepatitis B infection has remained low.

Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

 

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