What omicron's fast spread could mean for the U.S. – and the world

The first country to really get hit by omicron is South Africa.

Before the new variant took off last month, coronavirus cases there were low – only several hundred per day in mid November.

But by early December, the tally of daily infections had shot up to more than 4,500 — and genomic sequencing shows that omicron is to blame.

What's more, the variant quickly swept through all regions of South Africa – and has now shown up in about 60 additional countries.

Omicron hasn't yet triggered a global wave, but...