A fourth Covid jab is not yet needed, say UK experts, because booster doses continue to provide high protection against severe disease from the Omicron variant among older adults.
The World Health Organization (WHO) has warned against describing the Omicron variant as mild, saying it is killing people across the world.
India is bracing for a third wave of coronavirus as its largest cities - the capital Delhi and financial hub Mumbai - see a surge in cases.
China has put a second city into total lockdown after just three asymptomatic Covid cases were discovered.
The combination of Delta and Omicron variants is driving a dangerous tsunami of Covid-19 cases, the World Health Organization (WHO) chief has said.
Israel's top health adviser says the surge of Omicron cases could see the country reach Covid herd immunity.
The United Arab Emirates has announced that it will ban citizens who have not had three doses of a vaccine against Covid-19 from travelling abroad.
US health officials have halved the recommended isolation time for people with asymptomatic Covid-19 from 10 to five days, amid a surge in cases.
Former prime minister Gordon Brown says the failure to distribute vaccines to poorer countries is a "stain on our global soul".
People catching Omicron are 50% to 70% less likely to need hospital care compared with previous variants, a major analysis says.
