Most coughs in adults 50 and older come from viruses, not whooping cough infections

If you’re over 50 and a cough won’t quit, odds are good it’s an ordinary virus, not whooping cough. A study in Argentina tested hundreds of older adults with a recent cough. Most of these infections were viral, and whooping cough was found in just one person.

That’s reassuring, and it fits what many of us already guess when we hear a cough in the next room. It doesn’t change what you do when you’re sick. It just helps you know what you’re probably dealing with.

How the study worked

Researchers recruited 391 adults aged 50 or older who came to outpatient clinics at four hospitals in Argentina with a cough that had lasted 3 to 28 days. Each person had a nose and throat swab tested for many respiratory germs at once, and the team checked in by phone after 7 and 30 days. It ran from August 2023 to August 2024 and was published in 2026 in Medicina (Buenos Aires). It covered one year and four hospitals, so other years or places could look different.

What they found

A germ turned up in about two out of three swabs (65%). It was more likely when the cough was newer: 75% of people who had coughed fewer than 7 days tested positive, compared with 56% of those who had coughed 7 days or more.

Whooping cough, caused by a bacterium called Bordetella pertussis, was found in 1 of the 391 people, or 0.3%. Viruses were the main story. The swabs picked up 284 viruses and 8 bacteria. About 1 in 8 people with a germ had more than one at the same time: 34 such cases, or 13%.

About 5.6% of the people ended up in the hospital. The people most likely to be hospitalized were those who already had other health conditions when they came in. Their chance was several times higher than for people without those conditions.

Why does whooping cough still get attention?

Whooping cough has become more common among teens and adults since childhood vaccination became routine. Adults can pass it to babies, who are most at risk. Past studies around the world have found it in anywhere from 2% to 32% of adults with a cough. This study landed at the low end of that range. The authors note that whooping cough rises and falls in cycles, so a different year could show more of it.

What you can do today

Check your vaccine records. Ask your pharmacist or doctor whether your Tdap shot, the one that protects against whooping cough, is current. This matters most if you’ll be around a newborn soon. Many US pharmacies can look up your history and give the shot on the spot.