The Skeptical Teacher

Musings of a science teacher & skeptic in an age of woo.

Archive for August 31st, 2010

Why Vaccines Matter: Whooping Cough is Coming Back

Posted by mattusmaximus on August 31, 2010

When talking to people about the importance of getting vaccinated, I often hear the following argument, or some variation thereof: “Why should I bother getting vaccinated, because disease XXX isn’t even around anymore!” Of course, this is a perfect example of ignoring the reason why those diseases are kept in check (a.k.a. the incorrect cause fallacy); so many dangerous diseases are not an issue (or used to not be an issue) in industrialized society is due to widespread vaccination campaigns over the last few generations.  These diseases, such as pertussis (also known as whooping cough), are not completely gone, however – they are merely lying dormant.  In fact, because of the scare tactics put forth by many in the anti-vaccination movement over the last 20-30 years, vaccination rates have been dropping; and that gives an opening for these diseases to come back.  I can think of no other example which so clearly illustrates that pseudoscience & conspiracy mongering misinformation can kill.

And that is exactly what is happening – whooping cough is on the rise again, and rates of infection in the United States are increasing at alarming rates, and people (mostly children) are starting to die from an easily preventable disease. The bottom line really has to do with herd immunity, which basically states that if enough of the population is vaccinated against a particular disease, then not enough people can become infected to allow the virus to effectively propagate (which provides protection to those who, for whatever reason, cannot receive vaccinations).

If you think this isn’t a problem, think again.  The following Livescience.com article outlines very clearly why it is so important that we not become lackadaisical regarding these illnesses.  The solution is simple: talk to your doctor, get yourself vaccinated, and encourage those around you to do likewise…

Whooping Cough Makes Whopping Comeback

Christopher Wanjek
LiveScience’s Bad Medicine Columnist
livescience.com
Sat Aug 28, 2:55 pm ET

Whooping cough sounds fantastically antiquated, up there with scurvy and St. Vitus Dance – diseases you didn’t think anyone in America got anymore.

But whooping cough, named for the high-pitched “whoop” a person makes when inhaling, has made a comeback, with an incidence rate up by a whopping 2,300 percent since 1976, the year when fear of the vaccine began to take hold and vaccination rates started to plummet. In 1976 there were only about 1,000 reported cases; in 2005, the most recent peak, there were nearly 27,000 reported cases (and likely over 1 million unreported cases), according to the Centers for Disease Control and Prevention.

With outbreaks that cycle every three to five years, the respiratory tract infection might peak again this year, and the CDC recommends you get a booster shot soon.

We’re not off to a good start. In June, California declared a whooping cough epidemic after the death of five infants. So far there have been nearly 3,000 reported cases across six states, according to the CDC, a sevenfold increase compared with this time last year. Whooping cough season doesn’t really kick in until the fall.

A reversing trend

Whooping cough, known in the medical trade by its more conservative name, pertussis, is nearly completely preventable through vaccination. Pertussis was once a leading cause of infant death, with over a quarter million cases and about 8,000 total deaths annually in the United States during the peak years in the 1930s, just before the advent of the vaccine in the 1940s, according to CDC statistics.

By the 1970s, through vaccinations, whooping cough was as endangered as the whooping crane, with only about 0.000005 percent of the population infected. Unfortunately, fears that the DPT vaccine (a combo for diphtheria, pertussis and tetanus) could cause brain damage in rare cases – not entirely unfounded – gave rise to the anti-DPT movement in many industrialized countries.

At issue was the “whole-cell pertussis” element of the vaccine, since replaced in most countries, including the United States, with an “acellular” formulation (which includes purified proteins from the Bordetella pertussis bacteria), indicated by the “a” in DTaP, a common abbreviation for the vaccine these days. While never conclusively associated with brain damage, the original formulation was tied to other serious albeit rare side effects, such as allergic reactions and seizures.

Hype and consequences

The impact of the anti-vaccine movement was dramatic. In Great Britain, immunization rates for whooping cough dropped from over 80 percent to 33 percent (and in some regions to less than 10 percent) from 1974 to 1977. Then the epidemic hit. In 1979 there were over 100,000 cases and 36 deaths worldwide. In Japan in 1975, amidst public worry, the government suspended mandatory pertussis vaccines for infants; the 1979 epidemic killed over 40 children there. The same scene repeated itself in other countries, as well.

In June 2009 researchers reported in the journal Pediatrics that children who didn’t receive the whooping cough vaccine were 23 times more likely to contract pertussis. In the June 2010 issue of Pediatrics, researchers found no connection between the vaccine and seizures.

Herd mentality

The recent upsurge of whooping cough cases is not entirely the fault of the anti-vaccine movement. For the pertussis incidence rates to remain low – even among the vaccinated, because the vaccine isn’t 100-percent effective – there needs to be herd protection, in this case over 90 percent of the entire population immunized, to minimize the number of carriers.

Fewer than 85 percent of children are fully immunized against pertussis, according to the CDC. Some parents simply forget to keep up the multi-shot schedule. And for adults, vaccinated as children, the strength of the immunization has waned.

To curb the epidemic, the CDC is recommending that adults get a booster shot. Most adults have never received one and have never been told to get one.

Going natural is perhaps not the best bet. While pertussis is rarely deadly for otherwise healthy adults, struggling through the aptly named “100-day cough” isn’t particularly pleasant, with its uncontrollable fits of violent coughing around the clock.

Also, in the August 2010 edition of Clinical Infectious Diseases, James Cherry of the David Geffen School of Medicine at UCLA addresses a common myth that living through a bout of pertussis offers lifetime immunity. Not so. Protection from the vaccine and booster lasts longer, although no more than 10 years.

One limiting factor for a fully immunized population could be the fact that, for adults, the booster shot might not be covered by medical insurance. So your decision might come down to coughing it up now or coughing it up later.

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