Maternal immunization with Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine in The Gambia.
OBJECTIVE
To evaluate maternal responses to Haemophilus influenzae type b (Hib) polysaccharide-tetanus protein conjugate (polyribosylribitol phosphate-tetanus or PRP-T) given to pregnant Gambian women, the transplacental transfer of antibody, and the effect of maternal immunization on infant responses to the vaccine.


METHODS
An open, randomized immunogenicity study.


METHODS
A busy urban health center in The Gambia.


METHODS
A total of 451 pregnant women enrolled during the third trimester of pregnancy.


METHODS
Study participants were randomized to three groups. In one group, mothers were given PRP-T during the third trimester and their infants were given PRP-T at 2, 3, and 4 months of age. In the second group, mothers received PRP-T and infants were given inactivated poliovirus vaccine. In the third group, mothers received meningococcal A and C vaccine, and their infants received PRP-T.


METHODS
Anti-PRP antibody measurements of maternal cord, and infant blood.


RESULTS
Vaccinated women had a marked increase in total anti-PRP antibody (geometric mean titer 9.0 micrograms/mL), which was greatest in women in their first or second pregnancy. Previous tetanus vaccination during the same pregnancy and high concentrations of antitetanus antibody were associated with lower anti-PRP responses. In infants of PRP-T recipients, cord blood anti-PRP IgG concentrations were 61% of simultaneous maternal concentrations. In vaccinated infants of vaccinated mothers, geometric mean anti-PRP antibody concentrations at birth, 2 months of age, and 5 months of age were 1.92, 0.35 and 2.84 micrograms/mL, respectively, while in vaccinated infants of unvaccinated mothers, the corresponding concentrations were 0.29, 0.12, and 3.91 micrograms/mL. At 2 months of age, 60% of infants of vaccinated mothers and 26% of infants of unvaccinated mothers had anti-PRP antibody concentrations considered to be protective (>0.15 micrograms/mL).


CONCLUSIONS
In areas where much invasive Hib disease occurs in infants younger than 6 months, maternal immunization may help to reduce the risk of Hib disease in infants too young for immunization.
Mulholland
K
K
Medical Research Council Laboratories, Fajara, The Gambia.
Suara
R O
RO
Siber
G
G
Roberton
D
D
Jaffar
S
S
N'Jie
J
J
Baden
L
L
Thompson
C
C
Anwaruddin
R
R
Dinan
L
L
Glezen
W P
WP
Francis
N
N
Fritzell
B
B
Greenwood
B M
BM
D000907:Antibodies, Bacterial / Q000097:blood; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D005714:Gambia; D006192:Haemophilus Infections / Q000517:prevention & control; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D007112:Immunity, Maternally-Acquired / Q000276:immunology; D007115:Immunization Schedule; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D012044:Regression Analysis; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology*
D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D007074:Immunoglobulin G; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate