Measurement of tetanus antitoxin in oral fluid: a tool to conduct serosurveys

Background: Serosurveys that measure tetanus antitoxin can complement immunization coverage surveys to allow evaluation ol immunization services in developing countries. Measurement of IgG tetanus antitoxin in oral fluid was investigated as a practical and noninvasive alternative to and correlate of serum antibodies. Methods: Serum and oral fluid were collected from Malian infants. toddlers and adults (males without a history of tetanus vaccination). Specific IgG tetanus antitoxin was measured by enzyme-linked immunosorbent assay in serum (S-ELISA) and oral fluid (OF-ELISA). Results: One hundred forty-two pairs of serum and oral fluid samples were collected from infants, 35 pairs from toddlers and 35 pairs from adults. IgG tetanus antitoxin titers measured by OF-ELISA were 100-fold lower than those measured by S-ELISA but they correlated strongly (r = 0.90, P 12 months of age imply multiple prior contacts with immunization services. IgG tetanus antitoxin measured by OF-ELISA provides a logistically practical alternative for performing seroprevalence surveys.