Covid-19 cases are on the rise around the world, fueled by highly contagious variants of the coronavirus that occur far from where they were first detected.
The spread of these variants, scientists say, underscores how small random changes in the virus’s genetic code threaten to nullify progress in fighting a global pandemic that has killed at least three million people. Related variants are spread in the USA and Canada, Europe and Latin America.
Scientists say the variants can be controlled through public health measures that are now familiar, such as wearing a mask and social distancing, despite evidence that some strains could evade the immune response triggered by vaccination or a past infection.
In the UK, for example, where a variant known as B.1.1.7 caused a new fatal outbreak in winter, new cases slowed to a leak after a strict blockage and rapid vaccination process. .
Scientists also hope that the current vaccine harvest will limit at least the number of people who become seriously ill and die from Covid-19, even if the variants weaken the effectiveness of vaccines in preventing infection. Vaccine manufacturers are already testing new versions of photos that are set to attack variants.