Dec. 12: A Supreme Court judge in Brazil has ruled that foreign visitors will need to provide a Covid-19 vaccination certificate to enter the country.

The ruling invalidates regulations issued previously by the national health agency demanding only a negative PCR test for foreign arrivals.

The judge said it would be impossible to check all visitors and prevent the spread of the new Omicron variant. Lenient measures had made the country popular among non-vaccinated tourists.

The ruling is seen as another defeat for President Jair Bolsonaro, who has repeatedly undermined efforts to control the spread of the virus in one of the world's hardest-hit countries by the pandemic.

The president, who says he has not been vaccinated, had denied requests of the health agency Anvisa to demand vaccination proof from visitors.

Judge Luís Roberto Barroso said exceptions would be made for those coming from countries that had been unable to vaccinate most of their populations. They will need to quarantine on arrival for five days.

It is not yet clear when the new requirements will be introduced.

The announcement comes ahead of the country's busy summer season, with cities hosting popular New Year's Eve parties and Carnival parades.

But several celebrations have already been cancelled because of the Omicron variant. In Rio de Janeiro, the famous fireworks display at Copacabana beach on 31 December has been called off for the second year in a row.

Since the start of the pandemic, Brazil has reported 22 million Covid-19 infections and 616,000 deaths. About 65% of the population has been fully vaccinated.

The country has confirmed four cases of the new Omicron variant.