Q. A.

If you look at the phase one study, which was only a small study of 45 people, [the vaccine] induced neutralizing antibodies and at a robust level, equivalent to or better than what you see with natural infection. Historically, that is a good sign. I would guess that it’s going to be around 70 to 75 percent effective, but that’s purely a guess.

What do you say to people who won’t take a vaccine that only works three-quarters of the time?