Dear Science,

I appreciated your recent column about the autism/vaccine issue, but it didn't resolve a basic worry I have about vaccines for babies. I don't really know what's in vaccines (I've heard it's all sorts of horrible poisons). I also don't entirely trust traditional Western medicine to tell the whole story. I know vaccines have done great things for us, but I'm still skeptical. I want to do the right thing when I have kids—so what should a cynical future mom do?

Vaccine Waffler

Vaccines are an interesting bit of modern medicine—in many ways borrowing deeply from traditional, non-Western, and ancient medical thinking, and now referred to as inoculation. Healers had long noted that people do not get smallpox again after surviving the first bout of the disease. In order to protect people from dying of smallpox, healthy people who had never had it before were deliberately exposed to a small amount of "pus powder" from an individual with the illness. If the dosing was wrong or the powder too fresh, the patient would simply get smallpox; too little or too weak, and the patient wouldn't be protected. This practice—medical historians argue about exactly where and when it originated: India? China? Africa?—saved countless lives despite the risks.

The next breakthrough occurred in England, when Dr. Edward Jenner noted that milkmaids—exposed to a disease in cows related to smallpox—were protected from human smallpox. The cowpox virus, vaccinia, was close enough to smallpox to teach a human immune system to fight off the smallpox virus. But because cowpox had evolved in cows, it was (mostly) unable to cause disease in people—especially in comparison to the pus powders from the East. Vaccination was born. All of the childhood vaccinations are the descendants of these breakthroughs in Eastern and Western medicine.

The vaccines given earliest in childhood (at less than a year old) are made of key parts of pathogens or whole pathogens inactivated by being put into a sort of soap. These dead pieces truly cannot cause disease, only train the immune system. Only a few of the remaining vaccines are made up of viruses that are still "alive" (like the original vaccinations against smallpox), and they are carefully bred to not cause disease in humans. These strains are now tamed and demonstrated to be safe in generations of children.

Vaccines—compared to the alternatives of antibiotics, antiviral medicines, hospitalization, or intensive-care-unit stays—are natural and ancient techniques that have done more than just about anything (this side of clean drinking water) to increase human welfare. Science appreciates your open-mindedness and candor, and hopes this is a good starting point for a discussion with your child's pediatrician.

Respectfully Yours,


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