[Trial of prevention of severe Haemophilus influenzae type b infections and trial of tolerance, after PRP-T vaccination, in the Val-de-Marne region].
BACKGROUND
Protein-polysaccharide conjugate H influenzae vaccine is now routinely recommended for infants. To assess the vaccine's protective efficacy against invasive H influenzae infections and its safety, we conducted a study in the Val-de-Marne area of France.


METHODS
From April 1991 to April 1993, 22,443 children less than 5 years of age were given PRP-T vaccine. Infants less than 6 months were given three doses whereas those between 6 and 12 months received only two doses, and children over 1 year of age received one dose. According to the infant's DTP-IPV vaccination status, PRP-T was administered alone or reconstituted extemporaneously with DTP-IPV. The immunogenicity of the conjugate vaccine was assessed after three doses in 100 infants under the age of 6 months.


RESULTS
The PRP-T vaccine administered alone was safe. The reactions were more frequent when PRP-T vaccine was combined with DTP-IPV vaccine but they were comparable in frequency and severity to those observed after DTP-IPV vaccination. Before 1992, 18 Hib infections were reported each year in the Val-de-Marne region. During the study, only three Hib infections were reported each year.


CONCLUSIONS
The fall in incidence of Hib infections, greater than expected, suggests a widespread immune effect of the vaccine, possibly due to a decrease in Hib nasopharyngeal carriage. The antibody titres to each component of vaccine were comparable to those observed in previous clinical infant studies.
Boucher
J
J
ARDEA (Association pour la recherche et le développement en épidémiologie appliquée), Créteil, France.
Ethevenaux
C
C
Guyot
C
C
Leroux
M C
MC
Fritzell
B
B
Saliou
P
P
Reinert
P
P
D000914:Antibodies, Viral / Q000097:blood; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000009:adverse effects; D004361:Drug Tolerance; D005602:France / Q000453:epidemiology; D018073:Haemophilus Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D006193:Haemophilus influenzae / Q000276:immunology; D006801:Humans; D007223:Infant; D017778:Vaccines, Combined / Q000009:adverse effects
D000914:Antibodies, Viral; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D017778:Vaccines, Combined