At the South Africa National Institute for Communicable Diseases, scientists identified a coronavirus mutation that one scientist described as a “big jump in evolution”.

Within hours of the announcement, Israel, Singapore, and the United Kingdom imposed travel restrictions from Southern Africa. Ursula von der Leyen, European Commission president, also announced the EU will propose limiting air travel to union countries from the area due to concerns regarding the new variant.

Referred to by its scientific name, B.1.1.529, the virus contains a “very unusual constellation” of over 30 mutations. Ten of the mutations are in the spike protein alone, allowing the virus to evade the body’s immunity system more quickly, making it more transmissible. At the same time, the Beta variant has three, and the Delta variant has two.

Scientists are unsure how effective existing vaccines will be against the variant due to mutations that may make it resistant to neutralization. So far, twenty-two cases of the new virus variant have been identified, with two of them occurring in Hong Kong.

“All these things are what give us some concern that this variant might have not just enhanced transmissibility, so spread more efficiently, but might also be able to get around parts of the immune system and the protection we have in our immune system,” Richard Lessells, an infectious diseases specialist at the KwaZulu-Natal Research and Innovation Sequencing Platform, told the N.Y. Times.

While cases of the new variant are primarily concentrated in the country’s capital, Pretoria, according to experts, it’s only a matter of time before the virus reaches the rest of the country.

On Friday, South African scientists will meet with the World Health Organization technical team to discuss the new variant, which will be assigned a letter of the Greek alphabet.