title: Absence of Association between Cord Specific Antibody Levels and Severe Respiratory Syncytial Virus (RSV) Disease in Early Infants: A Case Control Study from Coastal Kenya.
abstract: BACKGROUND
  The target group for severe respiratory syncytial virus (RSV) disease prevention is infants under 6 months of age. Vaccine boosting of antibody titres in pregnant mothers could protect these young infants from severe respiratory syncytial virus (RSV) associated disease. Quantifying protective levels of RSV-specific maternal antibody at birth would inform vaccine development.
  
  
  METHODS
  A case control study nested in a birth cohort (2002-07) was conducted in Kilifi, Kenya; where 30 hospitalised cases of RSV-associated severe disease were matched to 60 controls. Participants had a cord blood and 2 subsequent 3-monthly blood samples assayed for RSV-specific neutralising antibody by the plaque reduction neutralisation test (PRNT). Two sample paired t test and conditional logistic regression were used in analyses of log2PRNT titres.
  
  
  RESULTS
  The mean RSV log2PRNT titre at birth for cases and controls were not significantly different (P = 0.4) and remained so on age-stratification. Cord blood PRNT titres showed considerable overlap between cases and controls. The odds of RSV disease decreased with increase in log2PRNT cord blood titre. There was a 30% reduction in RSV disease per unit increase in log2PRNT titre (<3months age group) but not significant (P = 0.3).
  
  
  CONCLUSIONS
  From this study, there is no strong evidence of protection by maternal RSV specific antibodies from severe RSV disease. Cord antibody levels show wide variation with considerable overlap between cases and controls. It is likely that, there are additional factors to specific PRNT antibody levels which determine susceptibility to severe RSV disease. In addition, higher levels of neutralizing antibody beyond the normal range may be required for protection; which it is hoped can be achieved by a maternal RSV vaccine.
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
authors.forename: Joyce Uchi
authors.initials: JU
authors.lastname: Nyiro
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.|University of Oxford, Oxford, United Kingdom.
authors.forename: Charles Jumba
authors.initials: CJ
authors.lastname: Sande
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
authors.forename: Martin
authors.initials: M
authors.lastname: Mutunga
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
authors.forename: Patience Kerubo
authors.initials: PK
authors.lastname: Kiyuka
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
authors.forename: Patrick Kioo
authors.initials: PK
authors.lastname: Munywoki
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.|London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: John Anthony G
authors.initials: JA
authors.lastname: Scott
authors.affiliation: Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.|School of Life Sciences and WIDER Centre, University of Warwick, Coventry, United Kingdom.
authors.forename: David James
authors.initials: DJ
authors.lastname: Nokes
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D000918:Antibody Specificity / Q000276:immunology*; D016022:Case-Control Studies; D005312:Fetal Blood / Q000276:immunology*; D006801:Humans; D007223:Infant; D007630:Kenya; D016017:Odds Ratio; D018357:Respiratory Syncytial Virus Infections / Q000097:blood* / Q000276:immunology* / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology*; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral