Dengue fever: Why is it so difficult to make an effective vaccine?

Amid growing dengue outbreaks around the world, 2023 could turn out to be one of the worst years on record for the infection. The World Health Organization (WHO) has said that dengue poses a pandemic-level threat, with outbreaks being reported in the Americas, Asia and Africa. Despite its prevalence and the threat it poses, the existence of different types of the virus and the way that they provoke immunity or complications mean that developing an effective vaccine has been notoriously difficult. …