There is a certain percentage of the population that objects to giving their kids vaccinations, because of stuff like Jesus, some book, Jenny McCarthy, whatever. You know, crazy people. Fine, in isolated instances. But when the crazy people reach a critical mass, we all die.
According to the WSJ, immunization rates have to be about 95% in order for the whole thing to work.
That’s just wrong, and (allowing for Gawker-style sensationalism) it’s not what the Journal said. Here’s what the paper actually wrote:
Health experts say a community needs about 95% of its citizens to be immunized against measles to ensure herd immunity, where vaccinating a large percentage of a population keeps even unvaccinated people from getting the disease. Even people who aren’t vaccinated, such as newborns, get some protection from herd immunity as the disease remains limited to a small part of the community
The Journal is saying herd immunity protects unvaccinated people, since high rates of vaccinations make it much less likely that viruses will keep finding unvaccinated people to infect. If you’re vaccinated against a virus, you’re almost certainly protected from it.
Here’s an October USA Today story on the 214 measles cases in the U.S. by that point last year:
Among those people infected, 86 percent were unvaccinated or their vaccination status was unknown. Thirteen percent were under one year old — too young for vaccination.
And here’s a National Institutes of Health graphic on how herd immunity works:
Living cheek to jowl with the unvaccinated hillpeople of the Pacific Northwest, your Audit Seattle bureau was forced to check with the doctor a few months back to be totally sure my vaccinated toddlers are safe from potentially unvaccinated kids at their day care (about one in four kids on Vashon Island, where doc says chicken pox parties are popular, have skipped some vaccines). They are. But I suspect a lot of people don’t know this.
Which you can see from the Gawker commenters. As far as I can tell, just one of the 478 commenters on Gawker’s post (300 more commenters than the original Journal story has, by the way) actually read the WSJ story and figured out that Gawker is wrong. But even she apparently didn’t bother to read the original info Gawker was misaggregating:
This kind of response was more common:
It’s true that vaccines aren’t 100 percent foolproof, and babies too young for vaccinations or people who can’t get them because of immune problems are obviously put at risk by poorly informed refusers who don’t vaccinate their kids.
But that’s a lot different than saying vaccinations don’t work at all unless 95 percent of us get them.
There’s way too much misinformation out there already on vaccines.
UPDATE: Seth Mnookin, who literally wrote the book on this stuff, responds to an email about whether I’m correct about the safety of vaccinated people from unvaccinated people and says that it’s a “little more nuanced” than what I wrote:
Measles is also unique because it’s one of the all-time most infectious diseases known to humanity and it can survive on its own (i.e., on doorknobs or wherever) for a few hours, which is why it has about a 90% infection rate (put someone with measles in a room with 10 unvaccinated people and 9 of them will get infected). So take an imaginary preschool of 45 two- and three-year-olds. Let’s stipulate that it’s in an area of the Pacific Northwest where vaccination rates are relatively low, so only 2/3 of the kids (30 kids total) have been vaccinated and 15 haven’t. Now let’s say that one of those unvaccinated kids goes to Switzerland, gets infected with measles, and shows up at school before he realizes he’s sick. You’d estimate that between 12 and 13 of the 14 other unvaccinated kids would be infected… as, in all likelihood, would the 1 or 2 kids who had been vaccinated but hadn’t developed full immunity.
So are vaccinated kids “safe” from infection? That depends on a whole range of factors. It’s probably worth pointing out that there have been recent cases where fully vaccinated children were infected; I just spoke with a mother whose fully vaccinated daughter was in a coma and lost all motor function after she was infected with Hib and developed meningitis.