The Israeli booster push is a possible success story, and a model for countries that can get access to adequate supplies of vaccine for population-wide booster rollouts, experts told The Daily Beast. Israel’s experience might also cast into relief U.S. authorities’ own hesitancy when it comes to boosters.

Despite the United States sitting on a huge stockpile of unused vaccines, the U.S. Food and Drug Administration and Centers for Disease Control and Prevention have authorized boosters for just a relatively small portion of the adult population.

Other countries should copy Israel, not the U.S., Ali Mokdad, a professor of health metrics sciences at the University of Washington Institute for Health, told The Daily Beast. “The science is clear and there is a need for a booster.”

But for a lot of countries, that might not be possible anytime soon owing to a shortage of doses. “Even considering a booster strategy is a luxury that most countries will not enjoy this year,” Andrea Taylor, a Duke University public health expert, told The Daily Beast.