ATLANTA — The whooping-cough vaccine given to babies and toddlers loses much of its effectiveness after three years — a lot faster than doctors believed — and that could help explain a recent series of outbreaks in the U.S. among children who were fully vaccinated, a study suggests.
The study is small and preliminary, and its authors said the results need to be confirmed through more research. But the findings are likely to stir debate over whether children should get a booster shot earlier than now recommended.
“I was disturbed to find maybe we had a little more confidence in the vaccine than it might deserve,” said the lead researcher, Dr. David Witt, chief of infectious disease at Kaiser Permanente Medical Center in San Rafael, Calif. Witt presented his findings Monday in Chicago.
The study was done in California, where whooping-cough vaccinations are a hot-button issue. The state had a huge spike in whooping- cough, or pertussis, cases last year, during which more than 9,100 people fell ill and 10 babies died. California schools have turned away thousands of middle- and high-school students this fall who haven’t gotten their booster shot.
