FIGURE 3.
Distribution of RSV antibody titers for 314 children who were RSV PCR+ and 583 who were not RSV PCR+. A titer >200 is consider positive for RSV antibodies. Sera were collected between the child’s first and second RSV season at approximately 1 year of age. RSV antibodies were detected by an EIA with tissue culture lysate from group A and group B infected cells as the antigen. The titer was estimated from a standard curve. Note the marked difference in number of specimens with low antibody titers, for example, less than 500, between children with RSV PCR+ infection (RSV PCR+) and children with no RSV PCR+ infection (Not RSV PCR+). EIA, enzyme-linked immunoassay; PCR, polymerase chain reaction; RSV, respiratory syncytial virus