The BA.2 sub-variant of Omicron and its sublineage BA.2.12.1 is estimated to make up more than 90 percent of the coronavirus variants in the United States as of April 16, the U.S. Centers for Disease Control and Prevention (CDC) said on April 19.

The U.S. national public health agency said on March 29 that the BA.2 sub-variant of Omicron was estimated to account for more than half the coronavirus variants in the country.

The U.S. Centers for Disease Control and Prevention (CDC) late on March 10 said some 98 percent of the U.S. population live in locations where COVID-19 levels are low enough that people do not need to wear masks indoors.

The BA.2 sub-variant of Omicron was estimated to be 11.6% of the coronavirus variants circulating in the United States as of March 5, the U.S. Centers for Disease Control and Prevention (CDC) said on March 8.

The U.S. Centers for Disease Control and Prevention (CDC) on March 3 said some 93 percent of the U.S. population live in locations where COVID-19 levels are low enough that people do not need to wear masks indoors.

The U.S. Centers for Disease Control and Prevention (CDC) on February 25 dramatically eased its COVID-19 guidelines for masks, including in schools, a move that means 72% of the population reside in communities where indoor face coverings are no longer recommended.

U.S. health officials said on February 16 they are preparing for the next phase of the COVID-19 pandemic as Omicron-related cases decline, including updating CDC guidance on mask-wearing and shoring up U.S. testing capacity.

Part of what is being discovered about the Omicron variant of Covid-19 is how fast it appears to infect people, a median of about three days, compared to four or five with other variants.

Top U.S. infectious disease official Anthony Fauci on Feb. 23 told CNN that he expects the U.S. Centers for Disease Control and Prevention to soon relax some Covid-19 recommendations aimed at curbing its spread for people who have been vaccinated.

The rate of first-time opioid prescriptions declined 54 percent between 2012 and 2017 in the U.S., largely because many doctors stopped prescribing the painkillers, according to a study of more than 86 million people covered by private insurance.