Molecular analysis of respiratory syncytial virus reinfections in infants from coastal Kenya.
BACKGROUND
Individuals are reinfected with respiratory syncytial virus (RSV) repeatedly. The nature of reinfection, in relation to RSV genetic and antigenic diversity, is ill defined and has implications for 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 wash samples collected during a 16-month period in 2002-2003, which spanned 2 successive epidemics.


RESULTS
Six infants were infected during both epidemics, 4 with RSV-A in the first epidemic followed by RSV-B during the second epidemic and 2 with RSV-A during both epidemics, with no significant G gene sequence variability between samples. Two infants were infected and reinfected with different RSV-A strains during the same epidemic. Possible viral persistence was suspected in the remaining 4 infants, although reinfection with the same variant cannot be excluded.


CONCLUSIONS
These are the first data that specifically address 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 (during an epidemic period).
Scott
Paul D
PD
Division of Immunity and Infection, University of Birmingham, UK. P.D.Scott@warwick.ac.uk
Ochola
Rachel
R
Ngama
Mwanajuma
M
Okiro
Emelda A
EA
James Nokes
D
D
Medley
Graham F
GF
Cane
Patricia A
PA
D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007223:Infant; D007630:Kenya / Q000453:epidemiology; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012008:Recurrence; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000145:classification* / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014760:Viral Fusion Proteins / Q000235:genetics
C502275:G glycoprotein, Respiratory syncytial virus; D014760:Viral Fusion Proteins