Cases of Covid-19 are growing worldwide, fueled by highly contagious coronavirus variants that appear far from where they were first discovered.
The proliferation of these variants, scientists say, underscores how small, random changes in the virus’s genetic code threaten to undo progress in overcoming a global pandemic that has killed at least three million people. The options are spread in the US and Canada, Europe and Latin America.
Scientists say options can be brought under control with already known public health measures, such as wearing masks and social distancing, despite evidence that some strains can avoid the immune response elicited by vaccination or past infection.
In the United Kingdom, for example, when a variant known as B.1
The researchers also hope that the current harvest of vaccines will limit at least the number of people who become seriously ill and die from Covid-19, even if the options weaken the effectiveness of vaccines to prevent infection. Vaccine manufacturers are already testing new versions of their photos, which are tuned to attack variants.