Monday, October 19, 2009

It's Just a Vaccine Kind of Day

I started the day listening to Kerri Miller's Midmorning program on Minnesota Public Radio, where a doctor from the Mayo Clinic and two other doctors discussed medical myths in general and myths about the H1N1 vaccine specifically for an hour.

The upshot (no pun intended):

  • The vaccine is functionally no different than the seasonal flu vaccine. If H1N1 had surfaced three or four months earlier, it would have been part of this year's seasonal vaccine.
  • The vaccines used in the U.S. are not made in China and meet FDA standards for safety.
  • They can be had with or without thimerosal if someone is concerned about that.
  • Pregnant women particularly should get innoculated. 28 women have died from the disease in the U.S. alone, so any theoetical risk of the vaccine seems to recede compared to that reality.
Green and white circle graphsLater, checking Boing Boing led me to a site called Information Is Beautiful, which has a wonderful illustration of the odds of complications or dying from the HPV vaccine, Gardasil, compared with the odds of dying from cervical cancer, car accidents, and a bunch of low-occurrence events like lightning and train crashes.

You'll have to look at it on the IIB site to read it, but the gist is that the dark green areas are the number of women who've had the shot -- the big one is the total, the little one you can just see here is the number who've had some type of complication (dizziness, nausea, headache) and the final green dot (invisible here) is the number of deaths (20 out of over 20 million doses). (The white circles with a green border represent the lifetime odds of dying of various causes; the big ones are cervical cancer and car crashes.)

Be sure to note the spot just below the tiny green dot that represents those 20 deaths: "There are no unusual patterns or clustering in the deaths that would suggest they were caused by the vaccine." -- CDC

Which means those 20 people could easily have died from some other cause or preexisting condition, like the 14-year-old who died from a large tumor in her chest, but whose death was reported as being caused by the vaccine.

Gregory Poland of the Mayo Clinic talked about this type of occurrence with the H1N1 vaccine on Midmorning today:
Kerri Miller: Every now and then, we get a report in the media that someone has died after having gotten a flu vaccine shot. And we'll find out a couple days later they had some other condition and it wasn't related to the vaccine, but the initial reports sound ominous.

Gregory Polland: That happens so frequently. That anecdotal, emotional reaction to hearing that someone has died and it's sort of in the fine print, three days later, that, Oh, well, they had a heart attack and they had known heart disease... If we give 30 million doses of this [vaccine], say, by the end of October to November, in that time frame by chance there are going to be people who die, people who have new diagnoses, women who have spontaneous abortions. And the list goes on and on. Some of those will happen by coincidence, within hours, days, weeks, of getting a vaccine.
Sandra Quinn from the University of Pittsburgh's school of public health pointed out that part of the reason people have an unscientific attitude toward vaccines is because we have all forgotten what life was like before vaccines were common. It's easy for us to have a lackadaisical attitude about vaccines because there is "herd immunity" for many of the diseases that are prevented by vaccines. But that herd immunity starts to break down when larger and larger numbers of people don't get their kids vaccinated.

According to pediatrics.about.com, "Herd immunity only works if immunization rates in a community are high, though, and can range from 85% for diphtheria to 92% for pertussis or whooping cough." The Wikipedia entry on what's called the Vaccine Controversy includes a litany of examples when vaccine rates have fallen and outbreaks of measles, whooping cough, and small pox have followed.

The final point I come back to on the issue of whether to vaccinate or not: Generally, the small risk of being vaccinated does not compare with the large risk of not being vaccinated.

2 comments:

susann said...

The new Nov. 2009 issue of Wired has a great cover story about vaccine fear that you have probably seen. One of the observations that stuck with me the most this week is that "rates of non-vaccination often correspond with higher levels of education and wealth." Noting this didn't make me feel any better about my heated argument with my own normally intelligent family member about getting the flu vaccines. Knee jerk distrust of experts and the lazy, sensationalist need to see correlations as cause and effect make me crazy.

Daughter Number Three said...

Yes, I saw the Wired article and read a long thread of comments about it on Boing Boing as well. Heard the author on NPR some time recently as well.

Slate has a good article on herd immunity that's been getting a lot of attention lately as well.

When writing my post on vaccines, I came across a jaw-droppingly stupid anti-vaccine site trying to sound authoritative on the subject of herd immunity. I still haven't gotten over it.