Evolutionary dynamics of RSV-A at the Kenyan Coast

What is it about?

RSV is the most important viral cause of pneumonia. Infection by RSV results in about 30m children requiring hospitalisation every year, of which 66,000-199,000 die. Most of the RSV burden ( >90%) is in developing countries. Using samples collected from children presenting with severe pneumonia between 2000 to 2012 in Kilifi and analysing RSV G-gene, we observed high genetic diversity in circulating RSV strains within and between epidemics in both local and global settings. On longer time scales (7 years) there is sequential replacement of genotypes, whereas on shorter time scales (one epidemic to the next or within epidemics) there is a high turnover of variants within genotypes. Further, this genetic diversity is predicted to be associated with variation in antigenic profiles.

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Why is it important?

It has been suggested that genetic variability and antigenic variation within the G protein contributes to the propensity of the virus to cause repeated individual reinfections and recurrent epidemics in communities by aiding evasion of host preexisting immune responses. These results provide an explanation for the recurrent RSV epidemics and have potential implications on the long-term effectiveness of vaccines.