Wood N, et al. - In this randomized clinical trial, researchers compared IgG antibody responses to vaccine antigens at 6, 10, 24, and 32 weeks of age between newborn infants receiving acellular pertussis (aP) vaccine and hepatitis B vaccine (HBV) or HBV alone. They suggested that the monovalent aP vaccine was immunogenic and safe in neonates and, if licensed and available, would be significant for newborns whose mothers did not receive the tetanus toxoid, reduced diphtheria toxoid, and pertussis antigen content [Tdap] vaccine during pregnancy.

Methods

• Among 440 healthy term (>36 weeks’ gestation) infants aged less than 5 days at recruitment, researchers performed this trial at 4 sites in Australia (Sydney, Melbourne, Adelaide, and Perth) between June 11, 2010, and March 14, 2013.
• They performed statistical analysis from March 1, 2015, to June 2, 2016.
• In this analysis, newborns received HBV and, after stratification by maternal receipt of adult-formulated aP-containing vaccine (tetanus toxoid, reduced diphtheria toxoid, and pertussis antigen content [Tdap]) prior to pregnancy, were block randomized to receive the aP vaccine (without diphtheria or tetanus) within 5 days of birth or not.
• Infants received a hexavalent vaccine with pediatric-formulated diphtheria, tetanus and pertussis antigens (DTaP), Haemophilus influenzae type b (Hib), HBV, and polio vaccine, as well as the 10-valent pneumococcal conjugate vaccine at 6, 16, and 24 weeks.
• Main outcomes and measures included detectable (>5 enzyme-linked immunosorbent assay units per milliliter) and geometric mean concentrations of IgG antibody to pertussis toxin (PT), pertactin, and filamentous hemagglutinin at 6, 10, and 24 weeks stratified by maternal Tdap history, and antibody at 32 weeks to HBV, Hib, polio, diphtheria, tetanus, and pneumococcal serotypes.
• Detectable IgG to both PT and pertactin at 10 weeks was the primary outcome.

Results

• According to the findings obtained, 440 infants (207 girls and 233 boys; median gestation, 39.2 weeks) were randomized to receive the aP vaccine plus HBV (n = 221) or HBV only (control group; n = 219).
• One hundred ninety-two of 206 infants who received the aP vaccine (93.2%) had detectable antibodies to both PT and pertactin vs 98 of 193 infants in the control group (50.8%) (P < .001) at 10 weeks, with the geometric mean concentration for PT IgG 4-fold higher among the group that received the aP vaccine.
• All infants (n = 181 with sera available for testing) who received the aP vaccine at birth had detectable PT IgG and significantly lower IgG geometric mean concentrations for Hib, hepatitis B, diphtheria, and tetanus antibodies at age 32 weeks.
• Findings revealed that local and systemic adverse events were comparable between both groups at all time points.