Immunogenicity of heptavalent pneumococcal conjugate vaccine in infants.
OBJECTIVE
To evaluate the safety, immunogenicity, and immunologic memory in young infants of a seven-valent (6B, 14, 19F, 23F, 18C, 4, 9V) pneumococcal vaccine conjugated to the outer membrane protein complex of Neisseria meningitidis. VACCINEES: Healthy 2-month-old infants 12- to 15-month-old control infants were recruited from participating private practices.


METHODS
Infants (n = 25) were vaccinated at 2, 4, and 6 months of age with the conjugated pneumococcal vaccine, followed by a single dose of licensed pneumococcal polysaccharide vaccine (n = 20) at 12 to 15 months of age. Thirteen infants who had not received the investigational pneumococcal conjugate vaccine served as control subjects and were given a single dose of the licensed pneumococcal polysaccharide vaccine at 12 to 15 months of age.


RESULTS
The investigational pneumococcal conjugate vaccine was well tolerated by infants. The vaccine was highly immunogenic in young infants, with significant increases in antibody to all seven serotypes after either two or three injections. At 12 to 15 months of age, infants who had been primed with the investigational pneumococcal conjugate vaccine had a brisk immunologic response to the booster injection of the licensed pneumococcal polysaccharide vaccine. Control infants, who received a single primary injection of the licensed pneumococcal polysaccharide vaccine, had negligible immunologic responses to four of the seven serotypes and low responses to the other three types.


CONCLUSIONS
The investigational seven-valent pneumococcal conjugate vaccine administered to young infants was well tolerated and highly immunogenic and provided immunologic memory to an injection of the licensed pneumococcal polysaccharide vaccine.
Anderson
E L
EL
Department of Pediatric, St. Louis University School of Medicine, Missouri, USA.
Kennedy
D J
DJ
Geldmacher
K M
KM
Donnelly
J
J
Mendelman
P M
PM
D001425:Bacterial Outer Membrane Proteins / Q000009:adverse effects / Q000276:immunology*; D004341:Drug Evaluation; D004797:Enzyme-Linked Immunosorbent Assay; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D022401:Meningococcal Vaccines; D009345:Neisseria meningitidis; D011008:Pneumococcal Infections / Q000276:immunology*; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial / Q000009:adverse effects / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000009:adverse effects / Q000276:immunology*
D001425:Bacterial Outer Membrane Proteins; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial; D018074:Vaccines, Conjugate