The discovery of a new coronavirus variant sent a chill through much of the world Friday as nations raced to halt air travel, markets fell sharply and scientists held emergency meetings to weigh the exact risks, which were largely unknown.
A World Health Organization panel named the variant “omicron” and classified it as a highly transmissible virus of concern, the same category that includes the delta variant. The WHO suggested the variant could pose greater risks than delta, which is the world’s most prevalent variant and has fueled relentless waves of infection on every continent.
Early evidence suggests an increased risk of reinfection compared to other highly transmissible variants, the WHO said. That means people who contracted COVID-19 and recovered could be subject to catching it again.
In response, the United States and Canada joined the European Union and several other countries in instituting travel restrictions on visitors from southern