From Staff Reporter Kibkabe Araya:
A rise in whooping cough cases among teens suggests that the pertussis vaccine may be wearing off sooner than expected, officials from the Centers for Disease Control and Prevention said Thursday.
After Washington state declared an epidemic in April, the CDC sent investigators here to learn the reason for the spike in cases. The investigation revealed a surprising number of cases among young teens, leading researchers to believe that pertussis vaccines can start to wear off by age 10.
Still, said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases, the vaccine offers very effective protection for several years.
The state continues to advise residents — adults and children — to get vaccinated. Nationally, 8 percent of adults have been vaccinated against pertussis.
“Vaccines have done a good job in protecting against pertussis, but our vaccines are not perfect,” Schuchet said during a Thursday teleconference with state Health Secretary Mary Selecky. “They don’t last as long as we would like them to.”
Pertussis, also known as whooping cough, is a highly contagious disease that can be fatal for infants who cannot handle the strong, consistent cough.
Infants and children under age 7 are immunized against pertussis with the DTaP vaccine. Children who miss a shot of the DTaP five-dose series, teens and adults receive the booster shot called Tdap. Infants and young children often get pertussis from adults who have not been vaccinated.
The DTaP vaccine is relatively new — introduced to the public in 1997 — so the wave of older children and teens experiencing an unusually higher number of cases used DTaP to prevent pertussis. Before 1997, children had the DTP vaccine, which is no longer used in the United States. The switch to DTaP came after DTP caused side effects like fever and swelling at the injection point, and some children had chronic neurological issues. But studies have showed inconsistencies in supporting this theory, Schuchat said.
The CDC found more than 75 percent of infants and children nationwide
Washington state were up to date with their DTaP shots.
Also a newer vaccine, Tdap, was introduced in 2005 to better protect teens and adults from pertussis. Around 43 percent of children ages 11-12 nationwide
in the state and 77 percent of teens ages 13-19 had their Tdap shots.
The state health department reports over 3,000 cases of pertussis cases so far this year, more than three times the number of cases in all of 2011. State officials continue to push for vaccinations mostly in adults, who only have 8 percent vaccination rate nationwide.