COULD DELAYING SECOND DOSE LEAD TO NEW VARIANTS?

Experts say delaying the second dose of some vaccines could lead to the emergence of new variants of COVID-19 — but there's no sign it has happened. Dr. Caroline Quach, chair of the federal government's National Advisory Committee on Immunization, said “there is a theoretical risk that if transmission is occurring at a higher rate in people who are partially vaccinated, or partially protected, with a very low protection, that variants could then develop that are going to be harder for vaccines to tackle.” The committee judged that wasn't a problem, because people should have sufficient protection in the first few weeks after they get vaccinated. But, she added, “we might be wrong.” Without enough vaccine or enough data, the advisory committee is trying to make “the best educated guess.” Dr. Andre Veillette, a member of the vaccine task force, said there's a concern the weaker immunity provided by one dose, especially in older people whose immune systems don't respond as well to vaccines, “may favour the selection of variants,” he said.