Whooping cough, also known as pertussis, is a highly contagious respiratory disease that produces, among other symptoms, a distinct cough. The name comes from the “whooping” sound infected people often make when they gasp for air after a fit of coughing.  “Whooping cough is an infection of the vocal cords,” Alan Lindemann, MD, an OB/GYN, explained. “They swell and don’t leave much room for air to go through. And it’s a bigger problem for children because they have a smaller larynx.” The disease can be serious or fatal for infants who are not yet old enough to receive their vaccine dose at 2 months old. Many whooping cough-related deaths and hospitalizations occur in newborns younger than 2 months. “This is the first vaccine approved specifically for use during pregnancy to prevent disease in young infants whose mothers are vaccinated during pregnancy,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, in a press release. The whooping cough vaccine is grouped with a class of vaccines called TDaP, an injection that protects against not only pertussis but also tetanus and diphtheria. The recently re-approved TDaP injection, Boostrix, has been around for years to protect adults and older children. What the FDA found after data analysis is that the vaccine was also remarkably good at shielding infants, whose pregnant parent had received a dose.  “Many medical societies have recommended vaccinating pregnant persons with a TDaP in the third trimester (27-36 weeks of pregnancy) to prevent infection with whooping cough in infants but Boostrix has now officially gotten FDA approval for this,” said Oladimeji Oki, MD, a family physician and assistant professor at Albert Einstein College of Medicine.

How Common is Whooping Cough in Babies?

Each year, thousands of cases of whooping cough are reported in every state. Annually, there have been between 10,000 and 50,000 cases of whooping cough since 2010. The country saw a 60-year high of pertussis in 2012 when the U.S. recorded more than 48,000 instances of the disease. Dr. Lindemann stressed that while babies are more susceptible to serious outcomes with whooping cough, adults can and do contract the disease as well. “[Adults] are less symptomatic because their vocal cords are bigger,” Dr. Lindemann said. “In other words, the passage of air through the larynx is bigger in adults and it doesn’t swell shut.” Of the whooping cough cases documented, many fatalities were in babies younger than 3 months with up to 20 babies dying from the illness each year. Before the whooping cough vaccine was widely accessible, the United States was averaging 200,000 cases of the infection annually.

Can My Baby Get Whooping Cough if I Was Vaccinated While Pregnant?

Before the FDA approved the Boostrix vaccine to prevent whooping cough in infants, they re-analyzed data from 108 cases of the disease in infants younger than 2 months against a control group of 183 infants who did not have the disease. What they found was that Boostrix was 78% effective in preventing whooping cough in newborns younger than 2 months if their parent had received the single-dose shot in their third trimester. After the preliminary analysis, researchers used data from published observational studies to update their findings and were able to confirm the 78% figure. So, while the efficacy percentage is high, there is still a chance that your baby can get whooping cough, even if you were vaccinated while pregnant. No vaccine is ever 100 percent effective. But it’s also important to consider that a baby’s only protection against the disease in their first 2 months of life are the antibodies from their parent’s vaccine while they are in utero.

Are there Dangers of Getting the Whooping Cough Vaccine While Pregnant?

The FDA did not report any serious adverse side effects from the vaccine. A study was conducted before approval with 680 pregnant people of which 340 were given the Boostrix vaccine and 340 given a saline placebo. After they gave birth, the placebo group was vaccinated with Boostrix. No vaccine-related effects on the pregnant person nor baby were identified through the study. Some reported side effects of those who received the vaccine were pain, redness at the injection site, fatigue, and gastrointestinal symptoms. “The whooping cough vaccine has been shown to be safe and effective in pregnant women with most side effects being minor,” Dr. Oki said.

What if I Don’t Get the Whooping Cough Vaccine While Pregnant?

For new parents who were not vaccinated while pregnant, Dr. Lindemann advises any adults around the baby to get the TDaP vaccine to prevent spreading the infection to a new baby who isn’t yet vaccinated. “The recommendation is for the [family] to get vaccinated because pertussis is relatively asymptomatic in older people,” Dr. Lindemann said. “In other words, it may just pass as the common cold. They may not know they’re sick. The FDA notes that babies need to be protected against asymptomatic spreading.” Dr. Oki recommends pregnant people get the vaccine as soon as possible if they are eligible. Those who did not receive their whooping cough vaccine while pregnant should get the injection shortly after delivery to prevent possibly spreading the illness. He also urges parents and caregivers to practice strong hygiene practices, especially hand washing. “Keep the infant away from anyone displaying any signs of illness, especially if there is a cough,” Dr. Oki said. “And practice good cough hygiene, meaning cover your mouth whenever you cough or sneeze.”