The coronavirus variant that emerged in the United Kingdom belongs to the world now, and mounting evidence is confirming some scientists’ early suspicions: It is a super spreader capable of turbocharging the pandemic and muscling less transmissible strains of the virus into oblivion.

Now that the new variant has established a beachhead in the United States and more than 40 other countries, the race to contain it is on.

That contest pits humans armed with vaccine, masks and hand sanitizer against a viral strain with a handful of genetic changes that has raised fears from the moment they were detected.