Jul 11, 2013

    2-year immunity if you survive dengue

    AN INFECTION from one strain of the dengue virus gives people protection against the other three strains for about two years, a new biostatistics study has found.

    That information should help researchers trying to develop vaccines against the mosquito-borne virus, which is nicknamed "break-bone fever" for the joint pain it causes.

    The study, by Thai and American researchers, was based on 38 years' worth of laboratory records from one children's hospital in Bangkok. By measuring how long each strain predominated and then faded in prominence, researchers could calculate how long protection lasted against alternate strains.

    It has been known since the 1940s that infection by one strain protects permanently against that strain, but only temporarily against others.

    Dengue is "sort of a Goldilocks virus for studying cross-protection", said study co-author Nicholas Reich, a biostatistician at the University of Massachusetts Amherst.

    Some pathogens have too many strains to measure accurately. Others have only a few strains, but mutate too rapidly. Dengue, he said, "is just right".