The World Health Organisation (WHO) urged countries to boost healthcare capacity and vaccinate their people to fight a surge in Covid-19 cases driven by the omicron variant, and said travel curbs could buy time but alone were not the answer.
Despite shutting its borders to travel from high-risk southern African countries, Australia became the latest country to report community transmission of the new variant, a day after it was found in five US states.
Omicron has gained a foothold in Asia, Africa, the Americas, the Middle East and Europe and has reached seven of the nine provinces of South Africa, where it was first identified. Many governments have tightened travel rules to keep the variant out.
"Border controls can buy time but every country and every community must prepare for new surges in cases," Takeshi Kasai, the WHO's western Pacific director, told a media briefing.
"People should not only rely on border measures. What is most important is to prepare for these variants with potential high transmissibility. So far the information available suggests we don't have to change our approach."
Kasai urged countries to fully vaccinate vulnerable groups and stick to preventive measures such as mask wearing and social distancing.
Omicron has been listed as a "variant of concern" by the WHO and scientists are still gathering data to establish how severe and contagious it is just as parts of Europe have been hit by surges of winter infections by the more familiar Delta variant.
Michelle Groome, a scientist with South Africa’s National Institute for Communicable Diseases, said the country was facing an unprecedented rise in infections due to omicron.
Almost 264 million people have been reported to be infected by the coronavirus since it was first detected in central China in late 2019 and 5.48 million people have died, according to a Reuters tally.
Vaccination rates vary from country to country but there are worrying gaps in poorer countries. Indonesia, the world's fourth most populous country and once Asia's Covid-19 epicentre, has fully inoculated only about 35% of its population.
Australia's chief medical officer, Paul Kelly, said Omicron was likely to become the dominant variant globally within months, but at this stage there was no evidence it was any more dangerous than Delta.
In the United States, the Biden administration announced measures to guard against the virus spreading. From Monday, international air travellers arriving in the United States will have to have obtained a negative Covid-19 test within a day of travel.
"We're going to fight this variant with science and speed, not chaos and confusion," US President Joe Biden said.
Fewer than 60% of the US population have been fully vaccinated, one of the lowest rates among wealthy nations.
Global travel curbs have accelerated with Hong Kong, the Netherlands, Norway and Russia, among others, announcing new measures on Thursday.
Aside from wreaking havoc in the travel industry, the clampdown has pounded financial markets and undermined major economies just as they were beginning to recover from the lockdowns triggered by Delta.
Germany said it would bar the unvaccinated from all but essential businesses, and legislation to make vaccination mandatory would be drafted for early next year.
Several countries, including Britain and the United States, were bringing forward plans to offer booster shots, but, like travel bans, they are controversial.
Many scientists say the way to stop the virus spreading is to make sure poorer countries have access to vaccines, not to give blanket booster shots to people in richer countries.
