Here's how the news is developing. All times Eastern.
Dec 28, 2021, 12:56 PM EST
Biden ends travel restrictions on 8 African countries
The Biden administration has ended its travel ban on eight African countries, citing increased knowledge of omicron and improved testing requirements for international travelers.
The ban was put in place in late November amid concerns about the new variant that was first found in southern Africa.
President Joe Biden said in a proclamation Tuesday, "Scientific experts have determined that people who are vaccinated against COVID-19 are protected against severe disease and hospitalization from the Omicron variant. Moreover, the Omicron variant has now spread to more than 100 countries, and it is prevalent in the United States. At the same time, my Administration has made international travel to the United States from all countries safer."
-ABC News' Allison Pecorin
Dec 28, 2021, 12:46 PM EST
Chinese city on lockdown
The Chinese city of Xi'an has 175 of the nation's 209 new COVID-19 cases, health authorities said.
Xi'an is under lockdown, leaving highways and walkways empty.
Aerial photo taken on Dec. 28, 2021 shows an empty overpass in Xi'an, China.
Xinhua/Tao Ming via Newscom
-ABC News' Christine Theodorou
Dec 28, 2021, 11:53 AM EST
Harris again tests negative after close contact
Vice President Kamala Harris' PCR test came back negative Monday, following close contact with a staffer who tested positive for COVID-19 on Wednesday, according to a White House official.
The staffer was with Harris throughout the day last Tuesday and tested positive the following morning, Harris' spokeswoman, Symone Sanders, said at the time.
Harris has been tested several times since that close contact, always testing negative, officials said.
-ABC News' Molly Nagle
Dec 28, 2021, 11:18 AM EST
Omicron accounting for about 58.6% of new cases
Last week, the CDC reported that omicron had overtaken delta to become the dominant COVID-19 variant in the U.S. However, on Tuesday, the CDC revised its initial estimates to noticeably lower numbers of omicron cases.
Last Monday, the CDC said omicron was estimated to makeup more than 73.2% of new cases as of Dec. 18. Now, the CDC says just 22.5% of new U.S. cases were estimated to be omicron as of Dec. 18.
People are tested for COVID-19 as the line for testing is seen in the foreground, at a walk-up testing site at Farragut Square, Dec. 23, 2021, just blocks from the White House in Washington.
Jacquelyn Martin/AP
According to new data from this week, the CDC says omicron is now estimated to account for 58.6% of all new cases, officially making it the dominant strain in the U.S. In the New York and New Jersey region as well as the deep South, omicron is estimated to account for more than 85% of new cases.
People line up for a free COVID-19 rapid test at a gas station in the Reseda section of Los Angeles, Dec. 26, 2021, as California braces for a post-holiday virus surge.
Richard Vogel/AP
A CDC spokeswoman said in a statement, "There was a wide predictive interval posted in last week’s chart, in part because of the speed at which omicron was increasing. We had more data come in from that timeframe and there was a reduced proportion of omicron. It’s important to note that we’re still seeing steady increase in the proportion of omicron."
ABC contributor Dr. John Brownstein, an epidemiologist at Boston Children's Hospital, said, "It may be possible that a large portion of their [the CDC's] sequencing data had come from labs that were specifically looking for s-gene samples, thus falsely elevating the percent omicron in samples."
