Whooping cough vaccination success – Why did it work?
It’s a triumph, no doubt about it.
There was not a single California death from whooping cough in 2011, one year after a record 10 infants died from the disease. This is truly good news, the first time since 1991 that no one in the Golden State has succumbed to the highly infectious illness.
So how did California go from such an awful record to such a good one? Let’s turn to the experts for an explanation.
In a press release last month, state health officials said three things led to the striking decline. There was greater general awareness of the disease this past year because of its deadly toll the year before. That, in turn, led to greater physician awareness, hence more rapid diagnosis and treatment. Finally, there were increased vaccination rates, due partly to the new state law that required all 7-12th graders to get a Tdap booster shot.
But a closer look tells a slightly different tale. When asked why the state was so successful, CDPH epidemiologist Kathleen Harriman agreed that 2010 apparently had a huge impact on awareness this past year.
“We put so many materials out there in 2010. We really put a lot of effort out there in 2010, from April on,” she said.
The biggest effort, though, was the state campaign to encourage hospitals to use Tdap, a combo vaccine that protects against diphtheria, tetanus and pertussis, or whooping cough. In fact, it may have been a game-changer.
“In the last big outbreak, that tool was not available,” Harriman said. “It was only licensed in 2005. There had been no pertussis vaccine for anyone over 6 – ever -- so it was never available before.”
The state urged post-partum women to get the vaccine. “We did a survey of hospitals to see how many were offering it, and only 25 percent were,” she said. “We decided to offer free Tdap to any hospitals that would participate. It was a big initiative.”
Still, they faced resistance. There were standing recommendations of who should take Tdap and when. Should people over 64 take it? What about people who recently had been given other vaccinations?
“There were barriers, like hospitals being afraid to give it,” Harriman said. “We made our own recommendations – ‘you can get it no matter when you received your last dose of tetanus or diphtheria vaccine.’”
So general awareness led to better and earlier diagnosis. And state public health officials worked hard to see that susceptible Californians – recent mothers in particular – got inoculated.
But one thing that likely had little effect on last year’s astounding low numbers was the much-ballyhooed new state law requiring 7-12th grade vaccinations. Most of those vaccinations didn’t occur until the last third of 2011, when the height of the pertussis season was over.
“It couldn’t have played a big role last year in terms of increasing population immunity,” said Harriman. But, she said, “Going forward we hope that it could do that.”