Protective immunity against respiratory syncytial virus in early life after murine maternal or neonatal vaccination with the recombinant G fusion protein BBG2Na.

Maternal and neonatal immunization were evaluated for their capacity to induce protective immunity against respiratory syncytial virus (RSV) lower respiratory tract infections in early life. Murine models were studied by use of a novel recombinant vaccine candidate, designated BBG2Na, which was derived in part from the RSV (Long) G protein. Maternal immunization resulted in the passive transfer of high levels of RSV-A antibodies to the offspring, which protected them from RSV challenge for up to 14 weeks. Indeed, protection correlated with the detection of RSV antibodies in the serum. Neonatal immunization with BBG2Na induced significant antibody responses even in the first week of life. Most importantly, these neonatal responses were not inhibited by the presence of RSV maternal antibodies. Consequently, the combination of maternal and neonatal immunization with BBG2Na resulted in the continual presence of protective levels of antibodies in the offspring.