COVID-19 vaccination delays could bring more virus variants, impede efforts to end pandemic - Fox Business

“That middle part, where you have a partially vaccinated population, or a partially immune population with lots of virus circulating, that’s kind of your danger point,” she said.

New variants could also reduce the effectiveness of Covid-19 vaccines and treatments and lead to reinfections among people who have already recovered from Covid-19, scientists say.

The key to minimizing these problems, they say, lies with social distancing and other measures to reduce contagion as well as with ramping up vaccination efforts, which have lagged behind in many places.