Most of the people who got whooping cough in San Diego County so far this year were up to date with their immunizations, according to county data.
Of the 621 people who contracted the illness, 85 percent had all their preventative shots — calling into question the efficacy of the vaccine.
“Pertussis vaccines offer high levels of protection within the first year of completing vaccinations,” said Dr. Wilma Wooten, a San Diego county public health officer.
“But then the protection decreases over time,” Wooten said.
KPBS and inewsource first raised questions about how well the vaccine worked in 2010, after its statewide analysis of the data showed the majority of people who got the disease were already vaccinated.
When Immunity Fails: The Whooping Cough Epidemic, a documentary co-reported by KPBS and inewsource, examined the worst epidemic in California in 60 years. One that made thousands sick and killed 10 babies.
The investigation led to several scientific studies which found that immunity faded sooner than expected after people were vaccinated.
Wooten said even with decreased immunity, the vaccine helps to lessen the severity of the illness.
Currently, children and teenagers are required to get a total of six shots to be considered up to date.
Of the 621 people who got whooping so far this year, 527 were up-to-date, 67 were not, and the immunization status was unknown for 27.
The vast majority, more than 400, were between 10 and 18 years old.
The number of positive cases so far this year has already surpassed total cases for last year, suggesting 2014 is on track to be as bad or worse than the 2010 epidemic.
