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Record year for whooping cough? Get the shots, health experts say

The U.S. is on course for a record year for whooping cough, health officials said this week. And while vaccinating kids is clearly the most important defense, health experts say adults may not realize they’re supposed to be getting regular shots, too.

Whooping cough, also known as pertussis, is a bacterial infection best known for causing a deep cough in children. They cough so long and so hard that when they can finally catch a breath, they make a distinctive “whoop” sound on the intake. So far this year, the United States has seen more than 16,000 validated cases of whooping cough, said Stacey Martin, an epidemiologist with the Centers for Disease Control and Prevention.

That’s more than the 15,216 cases reported last year. The latest peak was 27,550 cases in 2010, when it killed 27 people, 25 of them babies.

“We are on track to have a record year, I think,” Martin said in a telephone interview.

Pertussis has reached epidemic levels in the state of Washington, with more than 2,700 cases so far this year, and CDC is following outbreaks in 18 other states: Wisconsin, Minnesota, New York, New Jersey, Illinois, Idaho, Montana, Texas, Ohio, Iowa, Missouri, Florida, Arizona, Maine, New Mexico, Pennsylvania, Kansas, and Oregon.

"This time last year we had about 200 cases, which was a lot," said Tim Church, a spokesman for the Washington state department of health. "So to have 2,700 this time is just the most we have seen in my lifetime."

The problem is caused by a number of factors. Babies less than two months old are too young to get the vaccine, so they are especially vulnerable. And the formulation of the vaccine was changed in the 1990s to make it safer, but that also made it a little less effective, Martin said.

“We went to safer vaccine with fewer side effects but the duration of protection is not as good,” she said. Church adds that in Washington state, many parents have opted not to have their children vaccinated -- another factor that could affect the epidemic, although he said there is not data to demonstrate just how badly.

The good news is that 95 percent of U.S. children are vaccinated, Martin says. The bad news is that only 10 percent of adults are.

Children need five doses by age 6 to be fully protected and even then they may need a booster in their teens. Every adult should get at least one dose of the combined tetanus, diphtheria and pertussis vaccine, CDC says in its latest guidelines. The Infectious Diseases Society of America recommends the shot once every 10 years. 

"That’s been our big push in Washington state -- to help adults understand they need to get vaccinated too," Church said.

This is extra-confusing because there are several vaccines on the market, some of which contain just tetanus and diphtheria and some that also protect against pertussis, said Dr. Kathryn Edwards, who directs the Vaccine Research Program at Vanderbilt University in Nashville and who is a board member of the Infectious Diseases Society of America.

To protect the youngest babies, pregnant women should be vaccinated in the later stages of pregnancy, the CDC says. “I think it is hard to vaccinate pregnant women, because pregnant women have this feeling that they aren’t supposed to put anything in their body,” Edwards says. While this is understandable, studies have shown it’s very safe and the mothers-to-be pass on their immunity to their newborns, she said. This is the same for flu, too.

Even health experts often don’t realize the need for adults to be vaccinated. Edwards and colleagues surveyed 1,800 health care workers in 2007, and only 13 percent planned to get a whooping cough shot, with most saying they were unaware they even needed one. Half the time, when babies get whooping cough, a parent is the source, Edwards said. And whooping cough can make adults very sick, as well.

“Adults get whooping cough, and they cough and cough,” Edwards said. The cough can persist for weeks, but doctors and patients alike often don’t even think to check for pertussis. “Certainly, whenever adults need their booster for tetanus and diphtheria, they should include pertussis,” Edwards advised.

It’s not just whooping cough that adults need to be vaccinated against.

The CDC just released updated its adult vaccination recommendations to say adults should think about getting vaccines to prevent a range of diseases: chickenpox; measles, mumps and rubella (German measles); influenza (every single year); hepatitis A and B; and meningitis. Younger adults also need vaccinations against HPV or human papillomavirus, which causes cervical, penis and head and neck cancers (after about age 26 it’s too late), while adults older than 60 need a dose of vaccine against shingles and also should get a shot that protects against a batch of bacterial infections called pneumococcal diseases every five years.

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Washington State, California, Oregon and Vermont are all experiencing similar outbreaks. NBC's Dr. Nancy Snyderman reports.