Dr Kirsten Perret led a randomized trial on the effects of vaccines in pregnancy. The study involved 687 pregnant women from six countries, divided into two groups: the first took the diphtheria, tetanus and pertussis vaccine; the second took a placebo. Once the babies were born, doctors checked the levels of antibodies in mothers and babies. Children of unvaccinated women produce a greater number of their own antibodies to pertussis.
Nonetheless, this slight "deficit" is in fact irrelevant in clinical terms. The study in question shows in fact how maternal antibodies transfer to the newborn, protecting it more than effectively. The effect of these antibodies far exceeds that of any antibodies produced by the infant himself, protecting him for months. Their effect wears off after the newborn has been vaccinated. Doctors also checked for any negative effects of vaccines, both on moms and babies.
The two groups showed no difference: neither the vaccinated women nor the infants showed side effects. This means that the vaccination did not harm any of the subjects involved, proving safe. The team conducted the study to verify the safety of current Australian guidelines.
Gynecologists advise all pregnant women to get vaccinated between the 20th and 32nd week of gestation. Infants should instead be vaccinated around 2 months of age. This is enough to guarantee total coverage for children, avoiding infection and hospitalization.