Whooping cough, a very contagious respiratory disease that causes extreme coughing fits, is on the rise among adolescents who received a newer vaccine formula released in the 1990s. Turns out, the newer vaccines aren’t as effective over the long run as the original versions.
In a study published in the journal Pediatrics, researchers found that 69% of 11 and 12-year-olds were protected in the first year after receiving the Tdap vaccination, but after four years, just 9% were protected.
After the release of the original “whole-cell” vaccine back in the 1940s, rates of whooping cough, also called pertussis, dropped sharply. Before the shot was available, it was common for more than 200,000 cases to be reported in a year. By the 70s and 80s, that number was down to just a couple thousand.
But that vaccine caused temporary, but scary side effects, such as constant crying and fussiness, fevers, seizures and muscle weakness in babies. So researchers created the “acellular” vaccines to avoid those problems. The pertussis vaccines available today (called DtaP and Tdap) are all of this newer type. However, whooping cough rates have been steadily rising ever since, even though most kids are getting vaccinated.
The study also found that 10- to 16-year-olds had the highest rates of whooping cough during outbreaks in California in 2010 and 2014. The reason? That generation didn’t receive any doses of the old vaccine – only the new.
Experts worry that this will lead to more—and bigger—whooping cough outbreaks in the future.
So the new vaccines don’t work well. What should I do?
“Even though the vaccine’s protection wanes over time, I would highly recommend that patients stay up to date with the recommendations,” says infectious diseases pediatrician Zachary Hoy, MD, of The Children's Hospital at TriStar Centennial in Nashville.
The whooping cough vaccine, though not perfect, is still the best way to prevent infection. A 2013 study indicated that unvaccinated kids were 28 times more likely to develop whooping cough than children who received all their pertussis vaccinations.
“If you’re concerned about whether your child should receive the vaccine, you should talk to your doctor,” says Dr. Hoy.
While anyone can get whooping cough, it is especially dangerous to babies, whose immune systems aren’t able to fight the infection as well. The more people who get vaccinated, though, the less likely whooping cough will spread.
Vaccine recommendations
DTaP should be given to babies at two, four and six months, and then again at 15-18 months, and 4-6 years, to make it a total of five doses.
Tdap should be given to children and adults 11 years and older, every 10 years.
And pregnant women should get the vaccine during every pregnancy, sometime between 27 and 36 weeks gestation. This protects both the mom and baby.
Future of the vaccine
Researchers are on the hunt for a vaccine that doesn’t wane in immunity. According to Hoy, they are looking for ways to make vaccines last longer and blood tests that could help show how well a person is protected from pertussis.
Learn more about whooping cough.
