Romania's health ministry said it has detected the first two cases of the Omicron variant of the coronavirus in two Romanians who returned from South Africa on Nov 30.

The two travellers, a 48-year-old woman from the central county of Brasov and a 59-year-old man from the eastern county of Vaslui, were isolated in their homes and had no symptoms, the ministry said.

Authorities were sequencing a third test to identify virus variant, Reuters reported.

Romania has introduced travel bans for non-European Union citizens arriving from several African states and has sent planes to recover Romanians stranded by cancelled flights. The returnees are expected to quarantine for two weeks.

Ten people aboard a Norwegian Cruise Line ship approaching New Orleans have tested positive for Covid-19, officials said.

The Norwegian Breakaway had departed New Orleans on Nov 28 and is due to return this weekend, the Louisiana Department of Health said in a news release.

Over the past week, the ship made stops in Belize, Honduras and Mexico, according to AP. More than 3,200 people are on board the ship, officials said.

Australia has cleared the first Covid-19 vaccine for children aged five to 11, with the next stage of its vaccine rollout expected to start in early 2022.

Health Minister Greg Hunt said medical regulators had granted provisional approval for the Pfizer-BioNTech vaccine to be administered to younger children for the first time.

It follows similar decisions in the European Union, the United States, Israel and Canada, AFP reports.

Hunt said the vaccination of 2.3 million Australian children in the cohort will start on January 10, subject to approval from the nation's immunisation advisory body.

Denmark's prime minister has apologised after being filmed shopping without a mask four days after her government reintroduced mandatory face coverings in some places and on public transport, reports AFP.

The video, published on the website of the Ekstra Bladet newspaper, was taken on Friday by a passer by at a clothes shop in Copenhagen.

“It was simply an oversight after the new rules came into force,” Prime Minister Mette Frederiksen said on social networks. “I know it can happen to anyone. But ideally not me. So I obviously regret it and I want to thank you again for everything we are doing together to contain the epidemic.”

Britain has reported 42,848 new Covid-19 cases, reports Reuters, citing government figures.

The figures show a drop in daily cases following two straight days when more than 50,000 cases were recorded.

As many as 127 deaths have been reported within 28 days of a positive coronavirus test, down from 143 deaths reported on Friday.

Thousands of people marched through Vienna to protest against restrictions on public life designed to curb the coronavirus pandemic, reports Reuters.

Faced with surging daily infections, the government last month made Austria the first country in Western Europe to reimpose a lockdown and said it would make vaccinations mandatory from February.

People carried signs saying: “I will decide myself”, “Make Austria Great Again” and “New Elections” — a nod to the political turmoil that has seen three chancellors within two months — as crowds gathered.

Around 1,200 police officers were deployed to handle scattered protests that were supposed to merge into a march on the Ring boulevard in central Vienna. Police said they would remind marchers to wear masks and charge people who do not.

Sindh has recorded 178 coronavirus cases and four deaths over the past 24 hours, according to the daily situation report issued by the Chief Minister's Office.

The province's infection tally now stands at 475,599 and the death toll has climbed to 7,626.

Two hippos have tested positive for Covid-19 at Antwerp Zoo in Belgium in what could be the first reported cases in the species, Reuters has reported, quoting zoo staff.

Hippos Imani, aged 14, and 41-year-old Hermien have no symptoms apart from a runny nose, but the zoo said the pair had been put into quarantine as a precaution.

“To my knowledge, this is the first time in this species. Worldwide, this virus has been reported mainly in great apes and felines,” said the zoo's vet, Francis Vercammen.

Dutch health authorities have said the final tally of passengers on two flights from South Africa last week who had tested positive for the Omicron coronavirus variant was 18, reports Reuters.

The Netherlands' Institute for Health (RIVM) added in a statement that its investigation on passengers on the two flights has now been wrapped up.

The flights had already taken off on November 26 when the Dutch government introduced new travel restrictions due to worries about the newly detected Omicron variant.

More than 600 passengers travelling on the flights were kept isolated and tested for Covid-19, with 61 testing positive, including the 18 who were found to have the Omicron variant.