With about 26,000 new cases of pertussis recorded so far this year, 2012 has marked the largest outbreak of the disease in the past 50 years. Now scientists are calling for more vaccine research as a measure to fight the disease, also known as whooping cough, since immunity from the related vaccine eventually fades with time.
Developed in the 1990s, the whooping cough vaccine protected 98% of kids within the first year after injection. Five years later, however, only 70% remained protected, Centers for Disease Control and Prevention (CDC) epidemiologist Tom Clark told USA Today. A child could take all 5 recommended dosages by ages 4 to 6, and could still get the disease by age 10.
"We know the short-term protection is very good," Clark said. "But the protection is wearing off and that is the problem."
That's because the vaccine loses 42% of its effectiveness each year, according to Nicola Klein, co-director of the Kaiser Permanente Vaccine Study Center. She co-wrote a study detailing the problem published in The New England Journal of Medicine.
Declining vaccine effectiveness, combined with growing infection rates, means new R&D is necessary for an improved whooping cough vaccine with better long-term protection. But until a better vaccine becomes available, the best way to protect children, especially infants, is to stick with the vaccine already on the market. Even if a vaccinated child were to get whooping cough, the disease wouldn't be as severe as in an unvaccinated kid, according to Clark. The CDC is considering a booster shot for teenagers as a possible alternative.
- here is the USA Today piece