Fauci told Insider he thinks it’s a “prudent” move to simplify the US booster campaign, for two reasons — to bolster immunity among the vaccinated, and to clear up confusion, because most adults who are already eligible have not gotten boosted.

“Right now, don’t make it complicated,” Fauci said.

Fauci is hopeful that booster shots for all adults will help “keep people out of the hospital” and “keep people from dying,” the two primary goals of the US vaccination campaign.

He points to data from Israel, that shows booster shots provide an additional layer of protection on top of an initial vaccination, nearly zeroing out severe COVID-19 infections, and resulting in a 93% lower risk of hospitalization among people over age 40.

“The effect of boost is very, very favorable to preventing people from getting infected,” Fauci said.