Showing papers by "D. James Nokes published in 2006"

Molecular Analysis of Respiratory Syncytial Virus Reinfections in Infants from Coastal Kenya

Abstract: Background—Individuals are reinfected with respiratory syncytial virus (RSV) repeatedly. The nature of reinfections in relation to RSV genetic and antigenic diversity is ill defined and has implications to persistence and vaccine control. Methods—We examined the molecular relatedness of RSV causing primary and repeat infections by phylogenetic analysis of the attachment (G) gene in 12 infants from a birth cohort in rural Kenya, using nasal washings collected over a 16 month period in 2002-03 spanning two successive epidemics. Results—Six infants were infected in both epidemics, 4 with RSV-A in the first epidemic followed by RSV-B in the second epidemic and 2 infected with RSV-A strains in both epidemics with no significant G gene sequence variability between samples. Two children showed infection and reinfection with different RSV-A strains within the same epidemic. Possible viral persistence was suspected in the remaining 4 infants, although reinfection with same variant cannot be excluded. Summary—These are the first data specifically addressing strain-specific reinfections in infancy in relation to the primary infecting variant. The data strongly suggest that following primary infection some infants lose strain-specific immunity within 7-9 months (between epidemics) and group-specific immunity within 2-4 months (within an epidemic period).