The World Health Organization officially declared a new coronavirus variant in southern Africa “of concern,” naming it Omicron.

However, at present there is no evidence that the variant is more contagious or lethal, or that it may reduce the protective power of vaccines, but uncertainty on these questions contributed to the speed with which countries around the world moved to restrict travel from the region.

Earlier Friday, the European Commission proposed to its member countries to implement an “emergency brake” on travel from southern Africa and other affected countries to limit the spread of the new variant.

All air travel to these countries must be suspended until we have a clear idea of the danger posed by this new variant,” said Ursula von der Leyen, president of the European Union executive. “Travelers returning from this region must also comply with strict quarantine rules.”

What We Know

The virus, known scientifically as B.1.1.529, has a “very unusual constellation” of over 30 mutations. Of these mutations 10 are in the spike protein, allowing the virus to evade the body’s immune system more quickly and thus becoming more transmissible. In comparison the Beta variant has three, and the Delta variant two. Leading the W.H.O. to state in its official description. “Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other” variants.

Scientists are unsure how effective existing vaccines will be against the variant due to mutations that could render it immune to neutralization. So far, twenty-two cases of the new virus variant have been identified, two of which have occurred in Hong Kong.