On April 27, David D. Kirkpatrick reported in the N. Y. Times that Oxford's Jenner Center is close to starting human trials on a potential Covid-19 vaccine. According to Kirkpatrick, "ethics rules, as a general principle, forbid seeking to infect human test participants with a serious disease. That means the only way to prove that a vaccine works is to inoculate people in a place where the virus spreading naturally around them." It ain't necessarily...