Dr. William Haseltine says testing a Covid-19 vaccine on a healthy person is unethical and dangerous. "There are plenty of patients out there," he says, adding "it's uninformative because most of the people who [volunteer] are going to be young, and who really needs the vaccine are old people. Nobody in their right mind would give a live virus to an old, susceptible person... It's unethical. We have a good memory of the horrors of human experimentation starting in the 1940's and '50s ... do we r