Severe dengue virus infection in travelers: risk factors and laboratory indicators

BACKGROUND: Dengue fever is the most common arboviral disease in travelers. In countries where dengue virus is endemic, sequential (secondary) infections with different dengue virus serotypes are associated with disease severity. Data on severity and secondary infection rates in a population of travelers are lacking. METHODS: Intensified surveillance of dengue fever in travelers was performed within the European Network on Surveillance of Imported Infectious Diseases. Data were collected at 14 European clinical referral centers between 2003 and 2005. RESULTS: A total of 219 dengue virus infections imported from various regions of endemicity were reported. Serological analysis revealed a secondary immune response in 17%. Spontaneous bleeding was observed in 17 (8%) patients and was associated with increased serum alanine and aspartate aminotransferase levels and lower median platelet counts. Two (0.9%) patients fulfilled the World Health Organization (WHO) case definition for dengue hemorrhagic fever. However, 23 (11%) travelers had severe clinical manifestations (internal hemorrhage, plasma leakage, shock, or marked thrombocytopenia). A secondary immune response was significantly associated with both spontaneous bleeding and other severe clinical manifestations. CONCLUSIONS: In travelers, severe dengue virus infections are not uncommon but may be missed if the WHO classification is strictly applied. High liver enzyme levels and low platelet counts could serve as indicators of disease severity

A 2-dose regimen of a recombinant hepatitis B vaccine with the immune stimulant AS04 compared with the standard 3-dose regimen of Engerix (TM)-B in healthy young adults

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 greater than or equal to 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