Immunisation providers can be confident that mothers vaccinated against whooping cough during pregnancy pass on high levels of protective antibodies to their newborn, according to the largest pertussis vaccine trial to date.

The findings showed maternally transferred whooping cough antibodies persisted until babies received their own first dose at two months of age, supporting the current advice to vaccinate during pregnancy to prevent early cases in infants.

The randomised controlled trial included 687 pregnant women from six countries, including Australia, and assessed both the safety and immunogenicity of a single-dose diphtheria, tetanus and pertussis (Tdap) vaccine versus placebo at 27-36 weeks’ gestation.

The 346 women who received a placebo were given a crossover postpartum immunisation in the three days post-delivery, and pain was the most commonly reported adverse event, being similar in both groups.