Testing Zika Vaccines

Here's a question for you. Suppose that you had been working on a vaccine for the Zika virus, and now you have what you think might be a good one. How are you going to prove its safety and effectiveness?

Testing your vaccine for safety would be relatively easy; you'd give it to just a few people at first, and then to dozens, then hundreds of volunteers until you could prove that it was free of dangerous side-effects. But the real difficulty would be to prove that it is effective; that is, that it actually would prevent a Zika virus infection. Zika infections are relatively rare, even in Zika-infections regions. And you can't just test the vaccine on the persons who do become infected; vaccines have to be given before an infection occurs, not after.

So here are your options: 1) Administer the vaccine (or a placebo) to tens or even hundreds of thousands of healthy people in a Zika-infected region, so that just by chance you will have vaccinated a few people who will contact Zika at some time in the future, and then wait, or 2) administer the vaccine (or a placebo) to perhaps a few hundred volunteers and then deliberately infect them with the Zika virus.

Because Zika infections are relatively rare, the first approach is likely to be prohibitively expensive, time-consuming, and might never achieve the desired result. That's why researchers are proposing the second approach; deliberately infecting vaccinated and unvaccinated volunteers with Zika. The researchers argue that a Zika infection, like the flu or a cold, is a relatively minor illness for an adult. The real danger is to a woman who is pregnant, because a Zika infection during pregnancy can lead to serious birth defects in an infant. For that reason, the researchers say that any women in the proposed study would have to agree to avoid pregnancy for the duration of the study.

Still, some ethicists are queasy about the proposed study. Accidents (including unplanned pregnancies) happen. And this study would be of no benefit whatsoever to the persons who would choose to volunteer; they'd have to be doing it solely out of altruism.

What do YOU think?