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Study Proves Tdap Vaccine in Pregnancy Prevents Whooping Cough in Babies

A new report by the CDC shows how pregnant women can help prevent their newborns from catching this deadly disease.

Tdap Vaccine DonyaHHI/Shutterstock
Getting vaccines in pregnancy can sound scary, but they can be your baby's best chance at avoiding even scarier illnesses like whooping cough. A new study by the Centers for Disease Control and Prevention (CDC) published in the journal Clinical Infectious Diseases proves that getting the Tdap vaccine (tetanus, diphtheria and pertussis) in the third trimester drastically reduced babies' risk of developing whooping cough, which can be fatal in newborns.

Moms of sick babies weren't vaccinated

Looking at three years' worth of data from six states around the US, the research showed that the Tdap vaccine in pregnancy prevented most cases of whooping cough, also called pertussis, in newborns. "Our study found that vaccinating pregnant women at 27 to 36 weeks' gestation was 78 percent effective at preventing pertussis in babies less than eight weeks of age—i.e., when they're too young even to have received their first pertussis vaccine," study author Paul Cieslak, MD, medical director of Communicable Diseases and Immunizations at the Oregon Health Authority, tells Parents.com. Even more convincing evidence that the vaccine works showed it was 90 percent effective at preventing serious cases of the disease that required hospitalization.

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In 2012, the CDC issued its recommendation that women get the vaccine in every pregnancy, a decision supported by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics. "If the mother is exposed to a disease, she will make antibodies to it and give those antibodies to the child in the uterus and in the initial breast milk," David F. Colombo, MD, division chief of Maternal Fetal Medicine at Spectrum Health in Grand Rapids, Michigan, who was not involved in the study, tells Parents.com. "Giving the vaccine in the third trimester ensures that the mother will have higher antibody levels to pertussis so that she can give them to her child." Yet only 49 percent of women who delivered between fall 2015 and spring 2016 received the vaccine, according to the CDC.

In this new study, the mothers of babies who came down with the sickness were less likely to have been vaccinated. "We have no doubt that infants, especially those less than two months of age, are at very high risk for pertussis—high percentages of whom do require hospitalization—and most of the deaths from pertussis are suffered by these young babies," says Dr. Cieslak. The CDC says between five and 15 babies die every year in this country from whopping cough.

A dangerous disease, a safe vaccine

Whooping cough causes uncontrollable coughing that makes it hard to breathe, and is extremely contagious. Before the vaccine for children was developed, there were more than 200,000 cases a year in the US; that number dropped drastically to few than 10,000 after the vaccine came out. "The vaccine has significantly decreased the number of cases in the US," says. Dr. Colombo. But, that number has been on the rise again, and recent outbreaks have prompted renewed efforts at awareness of the importance of vaccination. In 2017 so far, more than 11,000 cases of whooping cough have been reported in the US.

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Despite what anti-vaccine websites say, this study and other research (including two studies from the UK and two from California) back up that Tdap in pregnancy is effective in preventing what we know to be a killer disease. "I get very concerned when people state that they refuse the vaccine or encourage other people around them to refuse the vaccine as well," Dr. Colombo says. "This leaves a group of unprotected people more susceptible to getting sick."

But what about safety? "It's always worthwhile to ask whether any medicine is safe to give during pregnancy, so we're always on the lookout for potential side effects," Dr. Cieslak says. "The data are convincing that Tdap is safe during pregnancy. Studies involving tens of thousands of women haven't found any risk to the baby."

While it has been recommended that caregivers receive the vaccine as well in order to protect your baby during his most vulnerable newborn stage, Dr. Cieslak says that strategy isn't very effective. "We know that trying to vaccinate mom and family members after the baby is born doesn't work very well," he says. Instead, the vaccine in pregnancy is a better method. "It's really good to know that we now have a strategy that's consistently proven effective," he says.