Over Easy: Correlation, Causation, and Preventable Diseases
In July 2013, famous “anti-vaxxer” Jenny McCarthy was hired to replace Elisabeth Hasselbeck on The View, causing a storm of protest, including my post on July 19 here at Over Easy.
Jenny McCarthy gained considerable notoriety with her unfounded and refuted claims that childhood vaccines caused her son’s autism. (It is unclear whether he even has autism.) The study she based her claims on was retracted by The Lancet, and its author, Andrew Wakefield, was stripped of his medical credentials. Thanks in large part to Jenny McCarthy, an anti-vaccination (“anti-vaxxer”) movement has sprung up in recent years since the Wakefield study, causing many parents to elect not to have their youngsters vaccinated. You can still read, “My child was normal and bright until he received the MMR vaccine, and immediately began showing alarming symptoms!” testimonials from anguished parents who flock to articles about the subject to comment, insisting that correlation between the vaccination and the onset of symptoms must mean that the vaccination caused the condition. Many scientific studies have refuted the link, but the belief persists.
Not everyone has bought into McCarthy’s schtick, however. According to Slate, she invited people to respond to a question about their ideal mate using the Twitter hashtag #jennyasks, and “got a dose of her own anti-medicine.” The results are probably not what she expected.
The purpose of this post is not to rehash the debate, but to point out the impact of the anti-vaxxer movement, which is beginning to show alarming results.
Before the U.S. vaccination program started in 1963, 400 to 500 people died from measles every year here. Tens of thousands more were made very ill and were hospitalized. Today, that number has dropped to almost—but not quite—zero. And that’s because of vaccines.
Cases of measles tripled here [in the US] in 2013, mostly due to anti-vaccination propaganda. There’s an outbreak in NYC going on right now, and one doctor isn’t afraid to point a finger right at the anti-vax movement. I don’t blame him; outbreaks tend to be centered in places where vaccine rates are low and someone traveling abroad brings the disease back with them.
An interactive map from the Council on Foreign Relations, Vaccine-Preventable Outbreaks, shows clearly how diseases that had been nearly eliminated have come roaring back in the past five years. The number of MMR vaccine recipients fell sharply during the 2000s, because charlatans like Jenny McCarthy and her often ignorant followers spread vaccine-autism hysteria. There was no effect on the incidence of autism, but it had a significant effect on the incidence of measles and mumps.
Vaccines.gov has an excellent diagram of Community or “Herd” Immunity that shows how vaccination affects the spread of illness. There are segments of the population — very young infants, those with compromised immune systems or allergies to components of the vaccine, etc. who cannot receive vaccinations of various kinds. The CDC has a comprehensive list of vaccines and who should not receive them at all, or should wait before being vaccinated.
I have seen reports of some physicians who refuse to treat unvaccinated individuals because of the risk to their other patients, especially vulnerable immune compromised individuals. There is some controversy among doctors about this decision, especially when parents claim a religious exemption from vaccinations.
But the fact remains that we are risking a comeback of preventible diseases, not only measles and mumps, but pertussis (whooping cough) and polio, which had been nearly eradicated. Michelle Bachmann spread the falsehood that the HPV vaccine, recommended for girls ages 9–14, causes mental retardation. Human papillovirus is the most common sexually transmitted infection, so common that nearly all sexually active men and women get it, and some types can cause health problems including cancers. But the HPV vaccine can stop this widespread health problem.
In the words of Phil Plait, author of the Slate article cited above,
…the lives we save may not be just our own, but that of the lovely toddler across the street, that of the carefree four-year-old next door, and every baby, every immune-compromised person, every elderly person we see. I’m even happy that my family’s own contribution to the herd immunity may save the life of some child whose parents didn’t vaccinate him.
No one deserves to die of measles. Of pertussis. Of polio. Of the flu. Talk to your board-certified doctor, and if they recommend it, get vaccinated.
UPDATE: BoxTurtle adds (comment #3) that there is a renewed outbreak of whooping cough, because the vaccines may be wearing off.
Why Whooping Cough Vaccines Are Wearing Off
Photo Credit: James Gathany, CDC