An open-label randomized study was undertaken to compare a 2-dose regimen (Months 0 and 6) of hepatitis B surface antigen (HBsAg) vaccine formulated with a novel adjuvant (HBsAg/AS04) with a standard 3-dose regimen (Months 0, 1 and 6) of licensed recombinant HBsAg vaccine in terms of immunogenicity and reactogenicity when administered to healthy subjects aged between 15 and 40 y. At 1 and 6 months after the full vaccination course there was a 100% seroprotection rate (anti-HBs > or = 10 mIU/ml) with the HBsAg/AS04 vaccine, compared with a 99% response rate with the licensed vaccine. The corresponding geometric mean titres were significantly higher for the novel vaccine compared to the standard vaccine: 15,468 and 2,745 mIU/ml at Months 7 and 12 vs. 6,274 and 1,883 mIU/ml, respectively. There was a higher prevalence of local symptoms with the adjuvant vaccine (90% of doses) than with the standard vaccine (48% of doses). However, these symptoms (pain, swelling and redness) were predominantly of mild-to-moderate intensity and resolved rapidly without treatment. A 2-dose regimen of the new HBsAg/AS04 adjuvant vaccine therefore compared favourably to the standard regimen in healthy young adults. It is anticipated that the simplified vaccination schedule may improve compliance and reduce costs.
143 people treated for tick-borne encephalitis (TBE) were included in a retrospective follow-up study. Sequelae and epidemiological characteristics in 114 individuals were analysed. The case fatality rate and the prevalence of residual paresis were low, 1.4 and 2.7%, respectively. However, 40 (35.7%) individuals were found to have a postencephalitic syndrome after a median follow-up time of 47 months, and a majority (77.5%) of these were classified as moderate to severe. Various mental disorders, balance and co-ordination disorders and headache were the most frequently reported symptoms. Increasing age was correlated to a longer duration of hospital stay, longer convalescence and increased risk of permanent sequelae. Results from a neuropsychiatric questionnaire showed marked differences between the subjects with sequelae compared to controls. 57% had noticed a tick bite before admission, and 48% were aware of at least one person in their environment who previously had contracted TBE. 79% were permanent residents or visited endemic areas often and regularly. In conclusion, we have found that TBE in the Stockholm area has a low case fatality rate, but gives rise to a considerable number of different neurological and mental sequelae, which justifies vaccination of a defined risk population in endemic areas.