SEROLOGIC CORRELATES OF IMMUNITY IN A TETRAVALENT REASSORTANT ROTAVIRUS VACCINE TRIAL

The correlation of antibody responses (serum rotavirus IgA and neutral izing antibody to serotype G1-G4 human rotaviruses and rhesus rotaviru s [RRV]) in a reassortant rotavirus vaccine trial with protection agai nst rotavirus infection or disease was investigated. Most subjects adm inistered 4 X 10(5) pfu of either the serotype G1 monovalent or seroty pe G1-G4 tetravalent vaccine seroconverted for at least one of the six antibodies (85% and 91%, respectively). However, fewer than one-third seroconverted to any prototype G1-G4 human rotavirus. Analyses of cov ariance indicated that higher prevaccination neutralizing antibody tit ers negatively affected postvaccination titers. Significant relationsh ips were found between several postvaccination rotavirus antibody tite rs and protection, and serotype-specific correlates of protection were identified between anti-Wa titers and G1 illnesses (P = .03) and betw een anti-RRV titers and G3 illnesses (P < .001). Overall, however, ser otype-specific immunity was no more significant than heterotypic immun ity, and no specific titer of any antibody analyzed was a reliable ind icator of protection.