Scientists say the world has reached a precarious point in the Covid-19 pandemic, one where conditions are ripe for the emergence of more new variants of coronavirus that could complicate efforts to control the disease.
The virus continues to spread rapidly in many parts of the world, even as parts of the population have acquired some degree of immunity from being infected or vaccinated.
Scientists say the combination – high rates of viral transmission and a partially immunized population – encourages the emergence of variants that are potentially more transmissible or deadly. More transmission means more opportunities for the virus to evolve, they say.
“When everyone has immunity, then virtually no virus is circulating and the virus cannot adapt,” said molecular epidemiologist Emma Hodcroft of the University of Bern, adding that if no one in a population has immunity, there is no pressure on the virus. . evolve. “That middle part, where you have a partially vaccinated population, or a partially immune population where a lot of viruses are circulating, that’s kind of your dangerous point,” she said.
New variants may also reduce the effectiveness of Covid-19 vaccines and treatments and lead to reinfections in people who have already recovered from Covid-19, scientists say. The key to minimizing these problems, they say, lies in social detachment and other measures to reduce contamination, and in ramping up vaccination efforts, which are lagging in many places.