New variants or strains of COVID-19 are appearing around the world, as it mutates like other viruses do and one big question being asked is, will existing vaccines protect people against the new versions of coronavirus?
The short answer is, scientists don't know yet. One of these new COVID strains was first seen in South Africa and several drugmakers say early tests indicate their vaccines aren't as effective against the South African strain as they are against the dominant strain spreading in the U.S.

Two companies, Moderna and Pfizer say they may develop booster shots if their existing vaccines don't work against new coronavirus strains.
America has seen a decrease in recent COVID-19 infections. On Sunday, just over 88,000 new positive tests were reported in the country and it was the first day this year that fewer than 100,000 were reported.
But a medical expert told cnn that the U.S. could be in the eye of the hurricane — meaning a decrease in cases that's only temporary because of the new disease variants that are spreading.
 1/2    1 2 下一页 尾页