Why are more contagious COVID variants emerging?

Why are more contagious COVID variants emerging?

By David Welch, Jemma Geoghegan, Joep de Ligt & Nigel French Why are more contagious variants emerging now, more than a year into the COVID-19 pandemic? New variants of SARS-CoV-2 have now evaded New Zealand’s border protections twice to spread into the community....