Whooping Cough Vaccine May Not Give Long-Term Protection
Study Suggests Protection From the Vaccine May Lessen After 3 Years
Revising the Immunization Schedule continued...
That's because the test used to screen for the disease shows only that a person is carrying the bug. That doesn't mean he or she has an active infection, says Michael Decker, MD, of Vanderbilt University in Nashville, Tenn.
The CDC says further research is needed.
"At this time, the data are too preliminary to warrant a change in timing of the adolescent booster dose, especially when it would impact the rest of the adolescent vaccine platform," says CDC spokeswoman Alison Patti.
Witt agrees the findings are preliminary and that further study is needed.
Still, Witt says, "The 11 deaths in California are a catastrophe. Our population has lost their fear of childhood illness."
The greatest fear is transmission to infants who cannot be fully vaccinated until they are 6 months of age, he says. "Families are at risk of transmitting to infants. We know the vaccine mitigates the impact, but it is still dangerous to younger siblings."
Witt recommends vaccination even while the optimal schedule is debated.
"We still find there was a higher risk among unvaccinated children in Marin County. Any group that is unprotected multiplies the risk to the rest of the community," he says.
Plus, vaccination appears to offer good protection for at least two to three years and may help symptoms to resolve more quickly, he notes.
About 8% of Marin County residents are not vaccinated against whooping cough, Witt says.
Whooping Cough in Adults
Illness can be severe, even in adults, according to Witt.
"We know there are ongoing outbreaks among adults. We know that adults represent a reservoir for the disease. We still have a large unimmunized herd that is a danger to young infants," he says.
The benefits of vaccinating beyond school age were questionable with the previous vaccine. But in the late 1990s, the nation started using a new type of whooping cough vaccine that has fewer side effects, making adult vaccination more feasible, he says.
Patti tells WebMD that preliminary results of a study of the new vaccine show "modest waning each year after, but still some protection even five years out."