About 33 percent of service members have declined voluntary coronavirus vaccinations, defense officials said Wednesday, acknowledging that more inoculations would better prepare the military for worldwide missions.

Nearly 150,000 service members are fully vaccinated, a panel of defense officials told lawmakers in a House Armed Services Committee hearing on the Pentagon’s coronavirus response. About two-thirds of troops who were offered the vaccine accepted it. There are about 1.3 million active-duty troops.

The acceptance rate “mirrors preliminary data that we see in other communities” of Americans, Air Force Brig. Gen. Paul Friedrichs, a Joint Chiefs of Staff health official, told lawmakers.

The military is collecting data on race and ethnicity among those who accept the vaccine, Friedrichs said in a discussion about reluctance that some communities have about the vaccine. But the officials acknowledged limitations in what they can do to compel troops to receive vaccinations.