Scientists say the world has reached a critical point in the Covid-19 pandemic, where conditions are ripe for the emergence of more new coronavirus variants that could complicate efforts to combat the disease.
The virus continues to spread rapidly in many parts of the world, even though parts of the population have acquired some immunity due to infection or vaccination.
Scientists say that a combination – a high rate of viral transmission and a partially immunized population – encourages the emergence of variants that may be more transmissible or lethal. More transmission means more opportunities for the virus to develop, they say.
“If everyone has immunity, you have almost no virus circulating and can not adapt to the virus,” said Bernem Hodcroft, a molecular epidemiologist at the University of Bern, adding that if no one in a population has immunity, there is no pressure on the virus to develop. “The middle part, where you have a partially vaccinated population, or a partial immune population with a lot of viruses 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 reducing these problems, they say, lies in social distance and other measures to reduce infection, as well as building up vaccination efforts, which have lagged behind in many places.