Researchers could soon have a better indication of how well vaccines protect against the new variant. But the Biden administration is already moving to urge as many Americans as possible to receive booster shots in coming days as the best means to protect against omicron.

That campaign is likely to involve messages urging people to get boosters and efforts to make sure the shots are available in as many locations as possible.

“The vaccinated people, the thing that we know for sure is that when you boost someone who’s been vaccinated with two doses of Pfizer or Moderna, you increase the level of neutralizing antibodies extraordinarily high — many fold higher than even the peak following the first two doses,” Anthony S. Fauci, President Biden’s chief medical adviser, said in an interview with The Washington Post.

Fauci said “it is quite conceivable if not likely” that booster shots will provide at least a partial shield of protection against the new variant.