Flu vaccine protects pregnant women against pertussis
Research by Wits scientists shows that pregnant women vaccinated against influenza also have less pertussis infection.
Pertussis, also known as whooping cough, is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis.
Wits researchers at the MRC Respiratory and Meningeal Pathogens Research Unit (RMPRU) published a paper in the New England Journal of Medicine, which shows that pregnant women vaccinated against influenza have 50 percent less pertussis infection than those not vaccinated.
Furthermore, pregnant women who received the flu vaccine were not only less likely to become infected with the flu virus throughout pregnancy and for six months after giving birth, but also had fewer infections by the Bordetella pertussis bacterium compared to unvaccinated women.
"This very interesting observation suggests that the benefits of the influenza vaccine extend beyond the direct protection against influenza infection, and informs us about the possible interactions between viruses and bacteria in the upper respiratory tract," says Marta C. Nunes, Associate Professor at the RMPRU and co-author of the paper along with Dr. Clare Cutland and Professor Shabir Madhi.
Because women who received the flu vaccine had less B. pertussis infections (for which the vaccine does not have a direct protective effect), researchers speculated that influenza infections predispose to co-infections with bacteria.
"So by preventing viral infections, we were also preventing bacterial super-infections that might be very severe," says Nunes, adding that flu vaccinations for pregnant women could curb severe pertussis disease in their babies later.
"Most severe pertussis disease happens before babies are immunized against pertussis. Household contact – particularly by mothers – is a major source of infection in infants, so combined flu and pertussis vaccination during pregnancy might have a cumulative benefit against B. pertussis infection in future."