With chronic asthma, food allergies and a heart condition, Thomas Silvera does everything he can to safeguard his health, including getting vaccines. So if and when a Covid-19 vaccine becomes available, he said, he’s leaning toward getting that, too.
But before vaccines reach the market, they go through wide-scale testing for safety and efficacy. The first two trials in the U.S. officially started Monday, from drug companies Moderna and Pfizer.
