Effects of maternal pertussis vaccination on infant immune response

Pertussis, “Whooping cough” caused by the Bordetella pertussis bacterium, is a highly contagious potentially life-threatening respiratory illness especially in infants less than 6 months of age. Recently there has been a considerable increase in pertussis activity with a sharp increase in incidence rate in infants < 2months of age who are too young to be protected through routine vaccination but with the highest risk of complications and death. A possible alternative way to protect these very young infants is by indirect protection, either through a cocooning strategy, i.e. vaccinating primary caregivers of new-borns, or by passive transfer of maternal antibodies induced by maternal vaccination. The purpose of this trial is to evaluate the possibility to provide initial immunological protection of newborn babies against pertussis infection by passively acquired maternal IgGs after vaccination of pregnant women. Pregnant woman will receive a single dose of a combination vaccine including reduced dose acellular pertussis, tetanus toxoid and reduced dose diphtheria toxoid (Tdap) between week 30 and 32 of pregnancy. The control group will consist of pregnant women who will be vaccinated with the same Tdap vaccine postpartum. All infants, born of pregnant women of both groups, will then be vaccinated with the routine vaccines of the national immunisation program (NIP) DtaP-IPV-Hib-Hep and PCV10 at the age of 3, 5 and 11 months instead of the standard schedule of 2, 3, 4, and 11 months. Experience in other countries and our own research has shown that vaccinations at age 3 and 5 months, followed by a booster dose will result in equal clinical effectiveness in protection against Hib, pneumococcus, diphtheria, tetanus and polio compared with a schedule which starts at 2 months of age. Infants will probably, up to 3 months of age, be protected through the presence of maternal pertussis antibodies (group 1) or by reducing the risk that new-borns will be infected by their parents by vaccinating their mother and partner or other primary caregivers (cocooning strategy, group 2). In this way the total number of vaccines each child gets can be reduced.

Obtain insight into the (difference in) pertussis-specific immunoglobulin G (IgG) levels in the first three months of life between infants whose mothers received a pertussis vaccine (Boostrix) during pregnancy in comparison to infants whose mothers received a pertussis vaccine immediately after having given birth.

IgG antibody levels against pertussis toxin (Ptx) at 3 months after birth

Pregnant woman in group 1 will receives a single dose of Boostrix vaccine between week 30 and 32 of pregnancy and pregnant woman in group 2 will receive a single dose of Boostrix vaccine postpartum. All partners or other caregivers will receive a single dose of Boostrix within 48 hours after birth.