SAFETY AND IMMUNOGENICITY OF A RECOMBINAN T PERTUSSIS-VACCINE IN PREMATURE AND TERM INFANTS

The aim of this study was to evaluate reactogenicity and immunogenicit y of a three-component recombinant acellular pertussis vaccine contain ing PT, FHA, and a 69kD protein or pertactin (Acelluvax - Biocine S.p. A., Siena, Italy) in 87 preterm infants born between 26 and 37 weeks' gestation (mean 32 wks) in comparison with 83 term infants. All infant s received at 2-4 months after birth three doses of the vaccine intram uscularly 8 weeks apart. Adverse reactions were absent or mild in both groups of infants. A significant increase (fourfold) of the antibody titers was obtained after the third injection in preterm infants; in 9 6% of them for them for the neutralizing antibody titer, in 91% for Ig G titers anti-PT and anti-pertactin and in 83% for IgG anti-FHA. A sim ilar increase was observed in 100% of term infants for th neutralizing titer and in 98%, 89% and 93% of them for the titers of anti-PT, anti -FHA and anti-pertactin. The geometric mean titers of IgG against all the three vaccine components as well as of the neutralizing antibodies obtained after the third dose were significantly lower in preterm in comparison with term infants. Nevertheless the levels of IgG anti-PT a nd of neutralizing antibodies are similar to or higher than those obse rved after immunization with traditional whole-cell vaccines or other acellular chemically detoxified pertussis vaccines and also after reco vering from spontaneous disease. In conclusion we can say that a three component recombinant pertussis vaccine, Acelluvax: is both safe and immunogenic in preterm infants starting the schedule at 2-4 months aft er birth.