The whooping cough vaccine isn’t just for kids. Adults need a one-time shot if they didn’t get the Tdap — the combined vaccine that protects against tetanus, diphtheria and pertussis – in their teens, according to the Centers for Disease Control and Prevention (CDC).

This shot cuts adults’ risk for pertussis — the super-contagious infection that triggers violent, rib-cracking coughs and sometimes pneumonia — by up to 70 percent. Even more important: Vaccinated adults can save young lives by shielding infants from exposure, the CDC says.

That’s why major medical groups including the CDC, the American Academy of Pediatrics (AAP) and the American Congress of Obstetricians and Gynecologists (ACOG) recommend that adults receive one dose of Tdap and that pregnant women get this important vaccine during each pregnancy.

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Whooping cough is on the rise in the United States, soaring from a national low of 2,900 cases in the 1980s to a high of 48,277 cases in 2012. The age group at highest risk: infants less than a year old, and especially those under three months, who have not yet received the full set of pertussis vaccines, recommended at ages 2, 4, 6 and 15 to18 months.

Babies may develop a high fever, seizures, pneumonia and brain damage, the CDC warns. And whooping cough can be fatal. Between 2000 and 2014, 241 of 277 pertussis deaths were in infants younger than three months old, according to government statistics.

Yet fewer than 18 percent of adults, including pregnant women, receive the vaccine, according to research by the federal government and the Michigan Department of Community Health.

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Pertussis is extremely contagious. Bordetella pertussis, the bacterium behind the disease, rides on tiny droplets pumped into the air with each forceful cough. A person without vaccine protection has up to an 80 percent chance of developing whooping cough if exposed to the germ, infectious-disease specialists warn.

Most babies catch it from family members…but friends and daycare workers transmit it, too. When CDC researchers tracked down the source of whooping cough in 569 babies from seven states for a 2015 study, they found that 66 percent likely caught it from a parent or sibling; another 14 percent picked up the germ from grandparents, aunts or uncles. In the same study, other adults who’d had contact with the babies were identified as the likely source of infection in five to 11 percent of cases.

The Tdap vaccine isn’t perfect. Just three to four people are fully protected from pertussis four years after getting the shot. If you do develop whooping cough, though, your symptoms may be milder than if you hadn’t been vaccinated. That’s good news for you, but means you could still spread the illness — a big reason health experts urge pregnant women to get vaccinated.

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Baby’s best shield is a vaccinated mother. Getting the Tdap vaccine during pregnancy transfers protective antibodies to your growing child, giving him or her protection in the weeks and months after birth, the CDC notes. A 2015 British study, conducted by Public Health England, concluded that vaccination during pregnancy reduced risk for whooping cough by 91 percent in infants younger than three months old.

ACOG and the CDC recommend having this vaccine between weeks 26 and 37 of pregnancy for best results. If you miss out, getting the shot after your baby is born will cut your risk for developing whooping cough and passing it along, according to the AAP. It may also allow you to pass on protective antibodies in breast milk, according to the CDC.

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Tdap isn’t for everyone. Skip it, government health officials advise, if you’re allergic to any component of the vaccine, have a history of seizures or Guillain Barré Syndrome or have had a serious reaction to vaccines for typhoid, diphtheria or pertussis in the past.

Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.