Preteen Whooping Cough Vaccine Loses Strength Over Time, CDC Finds
Preteen Whooping Cough Vaccine Loses Strength Over Time, CDC Finds
Results help explain recent surge in cases
To answer that concern, the study team zeroed in on a pertussis epidemic in Washington state in 2012. Five thousand people came down with whooping cough, many of them in their early teens, despite the state's 86 percent Tdap coverage rate.
Focus was placed on about 1,700 teens born between 1993 and 2000 -- kids who would have received the newer vaccine. This group experienced 450 cases of whooping cough.
Overall, Tdap effectiveness for this group was pegged at about 64 percent, but that plummeted to 34 percent two to four years post-inoculation, the investigators found.
Similar findings emerged from a Wisconsin study, leading the CDC to attribute the recent spike in whooping cough to a waning of Tdap effectiveness.
Going forward, CDC investigators said two things are needed: a better understanding of how exactly the pertussis bacteria works and an improved vaccine. But for the time being they don't recommend any shift in vaccine protocols.
Acosta stressed that expectant mothers should continue to get inoculated against whooping cough during their third trimester. Maternal inoculation "will protect the infant until they are able to receive their own doses at 2, 4, and 6 months of age," she said.
Another reason to get vaccinated, Acosta said, is that if an immunized person does become sick, the disease will be less severe.
Dr. Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia, expressed little surprise at the notion that Tdap effectiveness wanes with time.
However, "you're still better off getting the vaccine than not," he said.
"I think the path forward is to get a better vaccine," Offit added, "and people are working on that."
The study findings are published online May 4 in the journal Pediatrics.
Whooping Cough Vaccine Loses Strength Over Time
Results help explain recent surge in cases
To answer that concern, the study team zeroed in on a pertussis epidemic in Washington state in 2012. Five thousand people came down with whooping cough, many of them in their early teens, despite the state's 86 percent Tdap coverage rate.
Focus was placed on about 1,700 teens born between 1993 and 2000 -- kids who would have received the newer vaccine. This group experienced 450 cases of whooping cough.
Overall, Tdap effectiveness for this group was pegged at about 64 percent, but that plummeted to 34 percent two to four years post-inoculation, the investigators found.
Similar findings emerged from a Wisconsin study, leading the CDC to attribute the recent spike in whooping cough to a waning of Tdap effectiveness.
Going forward, CDC investigators said two things are needed: a better understanding of how exactly the pertussis bacteria works and an improved vaccine. But for the time being they don't recommend any shift in vaccine protocols.
Acosta stressed that expectant mothers should continue to get inoculated against whooping cough during their third trimester. Maternal inoculation "will protect the infant until they are able to receive their own doses at 2, 4, and 6 months of age," she said.
Another reason to get vaccinated, Acosta said, is that if an immunized person does become sick, the disease will be less severe.
Dr. Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia, expressed little surprise at the notion that Tdap effectiveness wanes with time.
However, "you're still better off getting the vaccine than not," he said.
"I think the path forward is to get a better vaccine," Offit added, "and people are working on that."
The study findings are published online May 4 in the journal Pediatrics.