Pertussis vaccine from pregnant women found to be safe, protects newborn

A new clinical trial revealed that vaccinating pregnant women with the Tdap vaccine both safely induces an immune response in women and is likely to protect newborn infants against pertussis.

The trial, conducted through a national network supported by the National Institute of Allergy and Infectious Diseases, was led by Carol Baker and Flor Munoz of the Baylor College of Medicine.

The researchers vaccinated 33 health pregnant women in the trial with a single Tdap dose and 15 pregnant women with a placebo during the third trimester of pregnancy. The safety of the vaccine was then evaluated, antibody responses induced in the pregnant women were measured and the immune systems of the infants were examined for a response to the vaccine.

No adverse pregnancy outcomes related to the vaccine were found, with Tdap-vaccinated pregnant women and their newborns reported to have significantly higher concentrations of antibodies against pertussis than women who received a placebo and their newborns.

The elevated antibody levels in those vaccinated continued for at least two months, which increased the likelihood that they were protected from pertussis during the time of greatest risk.

Rates of pertussis have been increasing in the U.S. since the 1980s, with more than 24,000 cases reported in 2013. Newborns younger than two months of age are considered too young to receive the Tdap vaccine, leaving them at an increased risk of complications and death if they contract pertussis.