On Apr. 18, 2022, the Military Health System reported that active-duty service members who received a COVID-19 vaccine booster shot were significantly less likely to be infected and show symptoms of the disease during the surge of the Omicron variant in the winter, according to a recent study.

As of Jan. 31, only 24% of active-duty service members who were eligible for a booster had voluntarily received the additional shot. By comparison, in the general U.S. population as of Feb. 10, about 46.8% of the booster-eligible population had received the additional shot.

The study found that service members were less likely to get a booster shot if they were younger, lower in rank or had lower education levels. Similar studies of the civilian population show that younger and healthier people have been less likely to seek out vaccines and booster shots.