For Quadmama: The Unvaccinated and the Vaccinated

Quadmama asked: Occasionally when I take my daughters to day care there is a sign posted saying some of the children have not been vaccinated. What risk does this pose to my children? Who is at a bigger risk in this situation: the unvaccinated kids or the vaccinated ones? I'm not trying to start a to-vaccinate-or-not debate, but I am curious about what all this means.

As I've mentioned before, I'm not a doctor and I knew, as big a topic as this is, that it needed an expert hand. I looked on Wikipedia on this, of course, but I didn't think it was good enough (though compelling in explaining why vaccinations are so damned important). I wanted an expert opinion damn it. Fortunately, I knew one. I contacted The Mother over on The Mother's Handbook and asked her to do a guest post for me. Fortunately for all of us, she complied. Without even calling me names.

She told me I could tone this down, but I'm not going to. I'll be frank. I look on those that think vaccinations haven't changed drastically (and for the better) the health of our children the same way I look at the Moon Hoax crowd. History is, in my opinion, unequivocal on this and, if you think simple childhood maladies can't kill, you don't know your history. My husband nearly died with chicken pox which manifested in his lungs. And he was born in 1983. I'm at a loss to understand parents who are willing to unnecessarily subject their children to disease. I'm not objective. To be honest, I don't know how you can know anything about science OR history and be so. Without more ado, here's The Mother.

Stephanie has asked me to field this question for her, being as she's a rocket scientist, and doesn't even play a doctor on TV. And I'm happy to do so, since I'm on record all over the blogosphere on this topic.

The answer to the first question is: it depends.

Herd immunity plays an enormous role in our protection from disease. Although vaccinated children should, theoretically, be protected from the diseases that they are vaccinated for, there are caveats.

The first is that some children don't mount the appropriate immune response to their vaccines. And we don't generally know which ones they are, because we do not routinely check titers for antibody response. It's not cost effective to do so, and as long as the children AROUND the non-responders are also vaccinated, herd immunity protects them from disease, just as if they, themselves, had developed antibodies.

The second is that some children are too young to develop an appropriate response to a particular vaccine. The vaccination schedule as currently recommended by the American Academy of Pediatrics is designed as it is largely because those dates are the very EARLIEST that a child can reasonably be expected to respond to that vaccine. If you have a little one who is too young to get, say, the MMR, and an unvaccinated child in the school contracts the measles, the youngster is at risk.

As to the second question: The unvaccinated children are, obviously, at great risk of developing dangerous, potentially lethal diseases that were on the brink of being eradicated just a decade ago, before all this anti-vax crap got started.

But yours MIGHT be just as at risk, for the reasons already mentioned.

Another risk: some vaccines "wear off." The biology behind this is fairly complicated, but the short version is that when a system isn't stimulated for a long time, the antibody-making cells just sort of disappear. We see this with tetanus, which is why we have always recommended a booster every ten years or so (tetanus comes from the soil, not from people, so it isn't part of the whole anti-vax risk scenario).

But the anti-vax movement has brought pertussis (whooping cough) back from oblivion. And our teens are starting to catch it, because their vaccines are wearing off. So current recommendations are that we send our teens back to the pediatrician for a TDaP (tetanus, diptheria, and acellular Pertussis).

The really, truly scary part of this wearing off phenomenon is that we honestly don't know what the wearing off risk is for immunity to some of the bugs that we thought were gone. Polio, for instance, is gone in America. But it's endemic in parts of Africa and India. Travelers to these areas are recommended to receive a polio booster.

In 1997, the US switched to using the IPV, a killed virus polio vaccine. This was done because polio had been essentially eradicated in the US. It is slightly less effective than the OPV, but carries fewer risks (the OPV is still the vaccination of choice in endemic areas, as it offers the best protection against all three wild strains).

Now imagine a traveler from India or Nigeria getting on a plane with an infective case of polio. If he or she runs into only vaccinated children, the virus won't have a chance to take hold in America. But if he manages to infect a few unvaccinated kids, we will have a new experiment on our hands. We will get to find out exactly what percentage of IPV receivers aren't immune to the wild virus. And we'll get to find out exactly what percentage of those vaccines wear off.

Terrifying, isn't it?

For an absolutely fabulous (and completely accurate) tutorial on the whole anti-vaccination movement, I refer you to Harriet Hall's impressive piece for eSkeptic magazine last week. She works through the entire hoax, from its beginnings in the laboratory of a doctor who received nearly $1million from plaintiff's attorneys, to the stupidity of Jenny McCarthy pitting her "mommy sense" against decades of scientific research.

And for a reminder of what the world used to be like, before vaccines, I refer you to David Oshinsky's excellent Polio: An American Story, about the scourge of polio, and the ordinary Americans who decided to fight back.

People forget. I think it's time we remembered.