A phase IV, multi-centre, randomized clinical trial comparing two pertussis-containing vaccines in pregnant women in England and vaccine responses in their infants

BACKGROUND: Pertussis vaccines containing three or five pertussis antigens are recommended in pregnancy in many countries, but no studies have compared the effect on infants’ antigen-specific immunoglobulin G (IgG) concentrations. The aim of this study was to compare anti-pertussis IgG responses following primary immunization in infants of mothers vaccinated with TdaP(5)-IPV (low dose diphtheria toxoid, tetanus toxoid, acellular pertussis [five antigens] and inactivated polio) or TdaP(3)-IPV in pregnancy (three pertussis antigens). METHODS: This multi-centre phase IV randomized clinical trial was conducted in a tertiary referral centre and primary care sites in England. Women were randomized to receive TdaP(5)-IPV (n = 77) or TdaP(3)-IPV (n = 77) at 28–32 gestational weeks. A non-randomized control group of 44 women who had not received a pertussis-containing vaccine in pregnancy and their 47 infants were enrolled post-partum. RESULTS: Following infant primary immunization, there was no difference in the geometric mean concentrations (GMCs) of anti-pertussis toxin, filamentous haemagglutinin or pertactin IgG between infants born to women vaccinated with TdaP(5)-IPV (n = 67) or TdaP(3)-IPV (n = 63). However, the GMC of anti-pertussis toxin IgG was lower in infants born to TdaP(5)-IPV- and TdaP(3)-IPV-vaccinated mothers compared to infants born to unvaccinated mothers (n = 45) (geometric mean ratio 0.71 [0.56–0.90] and 0.78 [0.61–0.98], respectively); by 13 months of age, this difference was no longer observed. CONCLUSION: Blunting of anti-pertussis toxin IgG response following primary immunization occurs in infants born to women vaccinated with TdaP(5)-IPV and TdaP(3)-IPV, with no difference between maternal vaccines. The blunting effect had resolved by 13 months of age. These results may be helpful for countries considering which pertussis-containing vaccine to recommend for use in pregnancy. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02145624, registered 23 May 2014 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12916-021-02005-5.