The level and duration of RSV-specific maternal IgG in infants in Kilifi Kenya

PLoS One. 2009 Dec 2;4(12):e8088. doi: 10.1371/journal.pone.0008088.


Background: Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants. The rate of decay of RSV-specific maternal antibodies (RSV-matAb), the factors affecting cord blood levels, and the relationship between these levels and protection from infection are poorly defined.

Methods: A birth cohort (n = 635) in rural Kenya, was studied intensively to monitor infections and describe age-related serological characteristics. RSV specific IgG antibody (Ab) in serum was measured by the enzyme linked immunosorbent assay (ELISA) in cord blood, consecutive samples taken 3 monthly, and in paired acute and convalescent samples. A linear regression model was used to calculate the rate of RSV-matAb decline. The effect of risk factors on cord blood titres was investigated.

Results: The half-life of matAb in the Kenyan cohort was calculated to be 79 days (95% confidence limits (CL): 76-81 days). Ninety seven percent of infants were born with RSV-matAb. Infants who subsequently experienced an infection in early life had significantly lower cord titres of anti-RSV Ab in comparison to infants who did not have any incident infection in the first 6 months (P = 0.011). RSV infections were shown to have no effect on the rate of decay of RSV-matAb.

Conclusion: Maternal-specific RSV Ab decline rapidly following birth. However, we provide evidence of protection against severe disease by RSV-matAb during the first 6-7 months. This suggests that boosting maternal-specific Ab by RSV vaccination may be a useful strategy to consider.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Antibody Specificity / immunology*
  • Blood Specimen Collection
  • Cohort Studies
  • Female
  • Fetal Blood / immunology
  • Humans
  • Immunoglobulin G / blood*
  • Immunoglobulin G / immunology*
  • Infant
  • Infant, Newborn
  • Kenya
  • Maternal-Fetal Exchange / immunology*
  • Models, Immunological
  • Pregnancy
  • Respiratory Syncytial Viruses / immunology*
  • Risk Factors
  • Seroepidemiologic Studies
  • Titrimetry


  • Immunoglobulin G