New understanding of dengue fever could help with vaccine

Some of the human immune system's defences against the virus that causes dengue fever actually help the virus to infect more cells, according to new research published today in the journal Science.

The researchers behind the work, from Imperial College London, hope their new findings could help with the design of a vaccine against the dengue virus. The study also brings scientists closer to understanding why people who contract dengue fever more than once usually experience more severe and dangerous symptoms the second time around.

Dengue fever is transmitted by a mosquito bite and is prevalent in sub-tropical and tropical regions including South East Asia and South America. Symptoms include high fever, severe aching in the joints and vomiting. The dengue virus can also cause haemorrhagic fever, which can be fatal.

Incidence of dengue fever has increased dramatically in the last century and two-fifths of the world's population are now at risk from it, according to the World Health Organisation. There are four distinct strains of the virus and no licensed vaccines or drugs have yet been developed to combat any of them.

The researchers behind today's study have identified a set of antibodies, produced by the human immune system to fight off the dengue virus, that they believe scientists should avoid including in any new vaccine to prevent dengue fever.

The new research shows that these precursor membrane protein (prM) antibodies do not do a very effective job of neutralising the virus. Moreover, these antibodies actually help the virus to infect more cells.