Results of the hepatitis A epidemic in Blekinge. Transmission links surveyed with the help of sequence analysis of viral RNA

: In 1994-1995 there was an epidemic of hepatitis A (HAV) among drug abusers in the county of Blekinge, Sweden. There were also a number of other cases in which the epidemiological links were unclear. In order to uncover possible links between unclear cases retrospective sequencing was carried out of the VP1 region of HAV-RNA from patient sera. It was found that the epidemic among drug abusers spread beyond their closest contacts, revealing links that would otherwise not have been suspected. The extent of the epidemic also demonstrated the need to vaccinate injecting drug users against hepatitis A.