WASHINGTON (NewsNation Now) — The Pentagon is deploying more doses of COVID-19 vaccines to the armed forces in the United States and overseas.

Vaccine fears have stopped some service members from stepping up to get the shot. As recently as mid-February, more than 400,000 active-duty troops were refusing shots — creating a potential threat to national security.

Now, more than a year into the pandemic, military leaders from across the services are seeing the beginnings of change in attitude. Non-profits and the Pentagon teamed up to educate troops, providing credible information on vaccines, through videos, town halls, and social media.

“We continue to see many individuals who were taking a wait and see approach now coming in for the vaccine,” Army Lt. Gen. Ronald J. Place, director of the Defense Health Agency, told reporters.

COVID-19 spread on the U.S.S. Theodore Roosevelt last year infecting more than 1,200 sailors, killing one, and sidelining an aircraft carrier in a critical area.

“As the vaccines have been around, as people have been getting vaccinated, we have seen an increase of a take of the vaccine,” Major General Jill Faris said.

Half a dozen House Democrats, led by Congressman Jimmy Panetta, penned a letter to President Biden last month, urging him to make vaccines mandatory for the military, arguing that not protecting troops from COVID is “a critical threat to our national security and public health.”

To date, the military has administered two million shots to service members and families. Officials say service members who are deployed and overseas receive top priority.

Recent problems with a batch of the Johnson & Johnson vaccine caused 15 million doses last month to be discarded, and officials say it has made it more difficult to provide shots for forces overseas, and that vaccines have been offered to service members’ families or other tier-two beneficiaries in only 40% of the military sites outside the U.S.

The loss in expected vaccines was a greater problem for the military because it had targeted the Johnson & Johnson shot for distribution overseas since it only requires one dose and doesn’t need the strict temperature controls that others do. Speaking at a Pentagon press conference Thursday, military officials said they are making up for the Johnson & Johnson shortfall by shipping more Moderna vaccines to forces outside the country. 

Some troops and their families overseas have expressed frustration at their inability to get a vaccine, particularly since many are in areas, including around Europe, that have been hard hit by the COVID-19 pandemic. Place said that in many locations the vaccines are still being offered only to tier-one individuals, which include troops who are deployed, health care or emergency workers, and beneficiaries who are 65 and older.

He added that while just 7% of the eligible Defense Department population is outside the U.S., the Pentagon is shipping 14 percent of the doses it gets to overseas locations.

“That said, if you’re a service member stationed overseas or a family member, likewise stationed overseas, and you haven’t received a vaccine and you don’t know when you’ll be able to, these numbers mean nothing,” said Place. “And it’s understandably frustrating.”

Place said that he expects to be able to deliver at least an initial dose to every eligible Defense Department person overseas who wants one by the middle of May.

National Guard leaders said Thursday that close to 18 percent of their forces – or more than 76,000 — have been fully vaccinated, and another 111,000 have gotten at least one shot. Guard troops are also working in many states to help deliver the vaccine, particularly in more remote or underserved locations.

There are more than 2,200 guard members spread across 1,000 different sites, including mobile vaccination centers, who are providing vaccines. As of this week, Guard members had administered 6 million shots to people around the country.

President Biden is leaving the decision on vaccines up to military commanders. White House press secretary Jen Psaki declined to comment today on our question about this, referring us to the Pentagon.

The Associated Press contributed to this report