The variants that could undo pandemic progress
As the world approaches 100 million coronavirus cases — including 25 million in the U.S. as of Saturday — questions are surfacing about new variants of the virus that could slow or even reverse the progress that has been made toward ending the pandemic.
One of those questions is how effective the current vaccines will be against these altered versions of the virus, which initially appeared in Britain, South Africa, Brazil and the U.S. Some appear to be more contagious than the original version, and all are little understood.
Prime Minister Boris Johnson has said that the variant first found in Britain might also be associated with a slightly higher chance of death, even as he acknowledges it is too soon to be sure.
Here are the latest updates and maps of the pandemic.
In other developments:

■ Taiwan ordered 5,000 people to quarantine on Sunday as it sought to contain a rare domestic cluster of Covid-19 connected to a hospital, Reuters reported.

■ In Hong Kong, the authorities said on Saturday that they had locked down part of the Jordan district and started to test everyone there, one of the most drastic measures that the Chinese territory has taken since the coronavirus surfaced there last winter.

■ Three men who are quarantining in Melbourne ahead of the Australian Open have tested positive for a highly infectious variant. The three men are not players. Only one player is known to have tested positive with the coronavirus — Paula Badosa, 23, of Spain.

■ New Zealand has reported its first coronavirus case in more than two months. The infected woman was a 56-year-old who recently returned from Europe and had quarantined at a hotel in Auckland.

■ Larry King, who interviewed presidents, movie stars and people from all walks of life, died on Saturday in Los Angeles at the age of 87. A statement from his media company did not specify a cause of death, but he had recently been treated for Covid-19.
The New York Times