Un-vaccinated kids don't explain rise in pertussis cases. - CDC official

[postulater]

There were more cases of whooping cough in the U.S. in 2012 than in any year since 1955, provisional data suggest. The disease, which still sounds a little old-fashioned to these young ears, has been on the rise in America since 1980. What's going on?

It's easy to blame parents who choose not to vaccinate their kids, based on anti-science beliefs. Indeed, researchers have found that unvaccinated kids have sparked whooping cough (scientifically known as pertussis) and measles outbreaks in certain schools.

Yet because their numbers are small, they're not enough to explain the overall U.S. rise. "We don't believe the small numbers of parents who are refusing pertussis vaccines for their children are driving the large numbers of cases we’re seeing across the country," Alison Patti, a health education specialist with the Centers for Disease Control and Prevention, wrote in an email response to my questions.

Instead, the CDC attributes the trend to doctors' increased awareness of the disease, improved diagnostic tests, and a newer version of the vaccine that kids began receiving in the 1990s. That last reason has gotten extra scientific oomph recently, with the publication of several studies over the past year.

http://www.popsci.com/science/article/2013-05/fyi-are-unvaccinated-kids-really-causing-resurgence-whooping-cough

Site shows a nice graph also. Interesting how the incidence of whooping cough was decreasing already by the time the first DTP vaccine was widely used.

[Warpy]

1. Most viruses tend to wax and wane in numbers of cases

The present increase in pertussis might be related more to vaccinated adults whose protection has long since worn off. There is now an adult vaccine available and anyone who is going to be around a young infant really needs to get it. Pertussis can be ugly in adults, but it's quite often fatal to infants who are too young to vaccinate.

[SheilaT]

2. Does this suggest that the vaccine is not as effective

as assumed?

I've never had whooping cough, and to the best of my knowledge I've never even been around it, and I'm 64. I wonder if the incidence was already decreasing simply because of better hygiene, since this is a bacterial infection. Just a guess on my part.

But along those lines, it's important to understand that the spread of various diseases in the past depended very much on people living in very unhygienic conditions, or alongside of their farm animals. We do live very differently these days, and that does make a difference.

[Warpy]

3. No, it wears off. See above.