Should travellers be offered vaccination against the dengue virus?

Infection with one serotype does not protect against the others, and sequential infections put people at greater risk for dengue hemorrhagic fever and dengue shock syndrome. Because of frequent repeated expositions and a high risk of importation in non-endemic regions, dengue infection has become a high priority public health concern and its prevention is a major issue. The overview report highlighted that in endemic countries vaccination reduced severe dengue by 93% and dengue hospitalizations by 82% among 9–16-year olds (efficacy rate 65.6%); however, an increased risk of hospitalized dengue was seen in the 2–5-year age group in year 3 of follow-up. [...]the vaccine efficacy against virologically confirmed symptomatic dengue was much lower among baseline seronegative participants (38.8%, 95% CI: –0.9–62.9%) in the first 25 months after the first dose of vaccine and an increased risk of hospitalized and severe dengue was found in seronegative individuals in a 30 months delay after the first dose [11]. A recent seroprevalence study in Italian travelers found that 12.2% were positive for dengue virus IgG and/or IgM [12] and similar rates were found in US travelers who lived in or visited dengue-endemic countries [13]. [...]the prevalence of dengue infection in travelers appears under the recommended threshold for immunization in endemic areas. [...]this vaccine is clearly not adapted to the overall population of travellers.Conflict of interest No conflict of Interest.Appendix A Supplementary data The following is the supplementary data to this article: