Predictors of travel-related hepatitis A and B among native adult Danes: a nationwide case-control study.
OBJECTIVE
To assess journey length and other predictors of travel-related acute hepatitis A (HAV) and B (HBV) virus infection among native Danes and determine the sensitivity and specificity of current pre-travel vaccination guidelines.


METHODS
A nationwide case-control study was perfomed involving 60 Danes with HAV and 14 with HBV who acquired hepatitis in non-western countries from 2000 to 2010. Non-immune travellers from a nationwide survey (1188 HAV and 1709 HBV) served as controls.


RESULTS
The odds ratios (ORs) for HAV and HBV increased with increasing journey length (p<0.0001). However, 90% of HAV and 62% of HBV cases travelled for less than 4 weeks, and the daily infection rate did not increase with journey length; rather, for HAV it decreased. Increasing age (p<0.0001) and journeys to Africa (OR 6.1 (3.2-11)) raised the risk of acute HAV. Travelling alone or with friends as compared to travelling with a partner/family (OR: 15 (3.2-134)) strongly predicted HBV risk. Danish vaccination guidelines had HAV/HBV sensitivities of 86%/31%, and specificities of 27%/95%, respectively. Incidence rates were 12.8 (HAV) and 10.2 (HBV) per 100,000 non-immune travel months, and acute disease severity affected HAV and HBV cases equally.


CONCLUSIONS
These results may support revision of current pre-travel vaccination guidelines.
Department of Infectious Diseases, Aarhus University Hospital, 8200 Aarhus N, Denmark. ullanise@rm.dk
Ulla Schierup
US
Nielsen
Reimar Wernich
RW
Thomsen
Susan
S
Cowan
Carsten Schade
CS
Larsen
Eskild
E
Petersen
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D022362:Hepatitis A Vaccines / Q000627:therapeutic use*; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D017325:Hepatitis B Vaccines / Q000627:therapeutic use*; D006801:Humans; D007114:Immunization / Q000592:standards*; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D014195:Travel; D055815:Young Adult
D022362:Hepatitis A Vaccines; D017325:Hepatitis B Vaccines