More countries are tightening their travel restrictions after a new coronavirus variant was identified in South Africa earlier this week.
The UK, Singapore and Japan are among those rushing in stricter quarantine measures and banning flights from South Africa and neighbouring countries.
The EU is proposing to ban flights from the region across the whole bloc.
Scientists still have much to learn about the variant, but say they are very worried about it.
The World Health Organization (WHO) has said it will take a few weeks to understand the impact of the new variant, as scientists work to determine how transmissible it is.
The variant is very different to the others that have emerged so far. Scientists have said it is the most heavily mutated version yet, which means vaccines, which were designed using the original strain from Wuhan, may not be as effective.
The new variant is yet to be given a more memorable name, like Delta or Beta, and right now is known as B.1.1.529. The WHO is expected to name it on Friday, and announce whether it is a variant of concern or just a variant of interest.
The WHO says so far fewer than 100 sample sequences have been reported. Cases have mainly been confirmed in South Africa, but have also been detected in Hong Kong, Israel and Botswana.
The UK’s health minister, Sajid Javid, said on Friday that it is “highly likely” to have spread to other countries.
Most of the cases in South Africa have been from its most populated province, Gauteng, of which Johannesburg is the capital city.
Only about 24% of South Africa’s population is fully vaccinated, which could see a rapid spread of cases there, Dr Mike Tildesley, a member of the Scientific Pandemic Influenza Modelling group (Spi-M), told the BBC on Friday.
