Study: Older Whooping Cough Vaccine More Effective
But it was phased out because of side effects; newer version works, study notes
The study included teens born from 1994 to 1999 who got their initial four shots of whooping cough vaccine before they were 2 years old at Kaiser Permanente Northern California.
Of the study participants, 138 teens had confirmed whooping cough. They were compared to 899 teens who'd had a lab test that confirmed they didn't have whooping cough, and to 54,339 "matched control" teens.
The researchers found that the fewer number of whole-cell vaccines a teen had received, the greater the risk of whooping cough.
Teens who had received all acellular vaccines had a 5.63 times greater risk of whooping cough than teens who'd gotten all whole-cell vaccines. Teens who received both acellular and whole-cell vaccines had a 3.77 times higher risk of whooping cough compared to those who had all whole-cell vaccines.
"The whole-cell vaccine may stimulate the immune response more, but there were a lot of safety concerns with that vaccine. We're really thinking the way forward is to develop a new vaccine," said Klein. But, she added, "Right now, make sure your children receive all their vaccines and boosters on schedule. This [acellular] vaccine does work, just not for as long as we would've hoped."
Dr. Kenneth Bromberg, director of the Vaccine Research Center and chairman of pediatrics at The Brooklyn Hospital Center in New York City, agreed that there's no going back to the whole-cell vaccine because of its side effects. "It's a moot point. We don't have whole-cell vaccine anymore," he said.
"The acellular vaccine doesn't last as long as the whole-cell vaccine, but it's not like it doesn't work. It does," he said. "And, it's a vaccine that's had almost all of the side effects removed."
Bromberg said it's important to make sure that those who are most vulnerable are protected, and in the case of whooping cough that's usually infants.
"Newborns and babies in the first few months of life are the most likely to die from pertussis," he said. "That's why the CDC recommends that pregnant women get the acellular vaccine in the last trimester of pregnancy. It will give their babies antibodies to protect them when they're most vulnerable."
Results of the study were released online May 20 in Pediatrics and will appear in the June print issue of the journal.