China shut down a city of 13 million people on Thursday in a bid to extinguish a tiny Covid-19 outbreak and chase its zero-case goal, as other nations around the globe battled huge infection surges driven by the Omicron variant.
Early studies from South Africa and Britain gave some cause for hope, however, indicating Omicron infections appear to result in fewer hospitalisations compared with the Delta variant.
But despite that initial data, scientists have warned that Omicron is highly contagious, driving record infection numbers in many countries and forcing governments to tighten virus controls.
China locked down the northern city of Xi'an -- home to the world-famous Terracotta Warriors -- to stamp out a cluster of several hundred cases.
"I think it is necessary to have the lockdown," a Xi'an resident, who wanted to be identified only as Yuan, told AFP.
Omicron has not been reported in Xi'an, with only dozens of cases of the less infectious Delta variant detected in the city of 13 million people in recent days.
But the Chinese government, in pursuit of its zero-case strategy ahead of the Beijing Winter Olympics, has reacted with typical forcefulness and ordered all Xi'an residents to stay indoors.
Only one person per household can go outside every two days to buy necessities, while non-essential businesses are closed.
February's Olympics are set to be the most restrictive mass sporting event since the pandemic began, with international spectators banned and all participants required to stay inside a closed-loop system.
In addition to mandatory vaccinations before landing in China, all athletes and personnel inside the bubble must undergo daily testing.
Those who test positive will not be able to participate, officials have said.
Europe has been hit hard by the ongoing surge, recording 60 percent of global cases over the past week, according to an AFP tally from official sources on Wednesday.
"We have to be more careful than ever in this period," Belgian Prime Minister Alexander De Croo said, with an impending wave threatening to overwhelm the country's already burned-out health workers.
The European Union's drug regulator last week allowed member states to use Pfizer's Covid treatment ahead of formal approval as an emergency measure against the Omicron wave.
And on Wednesday, Pfizer won US approval for the anti-Covid pill for high-risk people aged 12 and up.
Pills that are available at pharmacies are likely to be much easier to access than synthetic antibody treatments, which require infusions at hospitals or specialised centres.
The United States has spent $5.3 billion procuring 10 million courses of the treatment, according to the White House.
AstraZeneca said Thursday that a third, or booster dose of its Covid-19 vaccine "significantly" lifted antibody levels against the Omicron strain in a laboratory study.
While better able to bypass prior immunity, the Omicron variant is less likely to result in hospitalisation compared with Delta, according to the research from Britain published Wednesday.
The two preliminary studies, one from England and the other from Scotland, were cautiously welcomed by experts.
They stressed that any advantage in milder outcomes could still be negated by the new strain's heightened infectiousness, which may still lead to more overall severe cases.
"We're saying that this is qualified good news," said Jim McMenamin, a co-author of the Scottish research.
But healthcare workers in Europe have said there has not been much of a reprieve as they struggle to cope with a constant stream of patients, many needing intensive care.
Doctors and nurses are in a state of "extreme exhaustion", said Martial Moonen, head of the infectious diseases service at the public hospital in Liege, Belgium.
Several of the country's virologists and epidemiologists say they expect a fifth Covid wave to strike within days.
But Moonen said: "We are still going to try to make sure everyone gets their Christmas holidays".
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