Still, her mother’s age, medical condition and living situation put her at “very, very, very high risk for Covid,” Dr. Inouye said. “When you balance that tremendous fear, I just think the risk for her of getting Covid is so much higher than the risk of a side effect, which we know is going to be very rare.” Fear of side effects deterred Jeffrey Balkind’s wife from volunteering for the vaccine trials, but Mr. Balkind, 74, has stared down death twice — once during a 13-day hijacking in Pakistan in 1981, and again three years ago when his Vespa crashed. 