Here's what you need to know about the coronavirus right now:
Xian fights biggest outbreak in a Chinese city this year
The Chinese city of Xian reported another 155 local COVID-19 cases, taking the total number of cases to 1,100, the highest seen in any Chinese city this year, as infections keep spreading on Thursday eight days into lockdown for its 13 million people.
Samsung Electronics and Micron Technology, two of the world's largest memory chip makers, have warned the lockdown could affect their chip manufacturing bases in the area.
Experts question new U.S. CDC policy on isolation period
New government rules that halve the isolation period for asymptomatic coronavirus infections lack safeguards that could result in even more infections as the United States faces a record surge driven by the Omicron variant, disease experts said.
A major concern voiced by scientists is that the isolation policy fails to distinguish between vaccinated and unvaccinated people, who recover from the virus at different rates. It also does not require testing to confirm that a person is no longer infectious before they go back to work or socialize.
Omicron cannot escape body's second-line defense
A key part of the immune system's second-line defense - its T cells - are highly effective at recognising and attacking the Omicron variant, thereby preventing most infections from progressing to critical illness, a new study shows.
In test tube experiments, researchers in South Africa exposed copies of the virus to T cells from volunteers who had received vaccines from Johnson & Johnson or Pfizer/BioNTech or who had not been vaccinated but had developed their own T cells after infection with an earlier version of the coronavirus. "Despite Omicron's extensive mutations and reduced susceptibility to neutralizing antibodies, the majority of T cell response, induced by vaccination or natural infection, cross-recognizes the variant," the researchers reported on Tuesday on medRxiv ahead of peer review.
World nations try to balance Omicron restrictions
Global COVID-19 infections hit a record high over the past seven-day period, Reuters data showed on Wednesday, as the Omicron variant raced out of control and governments tried to contain its spread without paralysing fragile economies. Almost 900,000 cases were detected on average each day worldwide between Dec. 22 and 28.
Studies have suggested Omicron is less deadly than some previous variants. But the sheer number of people testing positive could overwhelm hospitals in some countries and leave businesses struggling to carry on without workers who government officials have ordered to quarantine. Governments are increasingly worried by the economic impact of huge numbers of people being forced into isolation because they had been in contact with a coronavirus sufferer.
Mexico authorizes Cuban COVID-19 vaccine for emergency use
Mexico's health regulator Cofepris said on Wednesday it had authorized the Cuban-made COVID-19 vaccine Abdala for emergency use, even though the shot has still not been approved by the World Health Organization (WHO). The vaccine received a "favorable technical opinion" from experts, Cofepris said in a statement.
Cuba has said its homegrown, protein-based vaccine Abdala is among the world's most effective, with more than 90% efficacy. Cuba, however, has not yet published results of its large-scale clinical trials in peer-reviewed journals. Abdala has been authorized for use in some other countries, including Vietnam and Nicaragua.
Reuters