When Will Wilson was diagnosed with AIDS in 2002, he relied on trips to Canada and credit cards to get the life-saving medication he needed.

The Affordable Care Act, passed in 2010, changed his life. Illinois expanded Medicaid under Obamacare in 2013, giving Wilson, who lives in Chicago, an even greater sense of security. Thanks to Medicaid, he pays nothing for his $3,000-per-month bottle of pills. Treatment has helped him bring his viral load — the amount of HIV in his blood — to an undetectable level, which prevents transmission.

"The biggest thing I've noticed is a sense of serenity,” Wilson, 64, told NBC News on World AIDS Day. "Before the passage of the Affordable Care Act, I worried almost on a daily basis."

Will Wilson, who has lived with HIV since 2002, poses for a portrait in downtown Chicago on Nov. 30, 2017. Wilson is currently receiving insurance through Obamacare's medicaid expansion. Alyssa Schukar / for NBC News

But, lately, that worry has returned. HIV/AIDS advocates say dismantling Obamacare — a signature goal of President Donald Trump's administration — will have a detrimental impact on Americans, especially LGBT and lower-income people, living with the disease.

Critics have expressed concern that Trump's executive actions on health care (and his support for failed GOP measures to replace the law) are indicative of his administration's indifference to combating HIV/AIDS, especially in comparison to his predecessors. Others, however, say they're withholding judgment as federal agencies like the Department of Health and Human Services, the National Institutes of Health and Centers for Disease Control and Prevention continue critical work.

Scott Schoettes, HIV Project Director at Lambda Legal and one of six members who resigned in protest from the Presidential Advisory Council on HIV/AIDS in June, said Trump has consistently failed to lead on the issue.

"I don’t think anyone at the White House is paying attention to this," Schoettes, who is HIV-positive, told NBC News. "The HIV crisis and epidemic has not disappeared, it just disappeared from public view."

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The State Department issued a recent report reaffirming the country's commitment to foreign aid for HIV/AIDS, but there's no sign yet of a domestic strategy, advocates said.

More than 10 months into his first term, Trump has yet to appoint an HIV/AIDS czar, making him the first president without one since President Bill Clinton created the position in 1993. Trump has not appointed someone to lead the White House Office of National AIDS Policy, and the office's informational page on the White House website is blank. Ten members remain on the Presidential Advisory Council, which Clinton also created in 1995, and its first and only meeting happened in August. The committee sent a letter to former HHS Secretary Tom Price warning him that repealing Obamacare would cause "catastrophic damage" to HIV prevention.

A White House spokesperson did not respond to a request for comment on this article.

John Peller, the president of the AIDS Foundation of Chicago, said the HIV/AIDS crisis requires a national approach.

"The scientific advances that we’ve made in over just the past five years put us in a position nationally that we really have an opportunity to talk about getting to zero new HIV cases or ending the HIV epidemic in a reasonably short time frame," he said. "We believe that a Republican administration that's focused on saving taxpayer dollars should embrace that as a goal."

But the White House budget proposal earlier this year would have slashed nearly $1 billion from HIV-related programs across the federal government. (The cuts were ultimately rejected by Congress.) Other Trump-backed policies not strictly health care-related have caused concern, like the Republican tax bill headed to a vote Friday in the Senate. The bill includes a proposal to repeal Obamacare's individual mandate, which experts say could cause premiums to spike and leave millions uninsured.

"For the Trump administration to turn around and say we're going to everything we can to undermine the Affordable Care Act and make it harder for people to enroll, which would be harmful and would reduce health care coverage for people with HIV and other chronic diseases, is taking us in the wrong direction," Peller said.

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Before Obamacare, people with HIV had trouble getting insurance because of pre-existing condition exclusions, Medicaid limitations and steep costs. Coverage for people with HIV increased nationwide after the law was enacted, from 36 percent in 2012 to 42 percent in 2014, mainly due to the Medicaid expansion, a recent study by the Kaiser Family Foundation found. Annual HIV infections in the U.S. fell 18 percent between 2008 and 2014, according to the Centers for Disease Control and Prevention.

Carl Schmid, deputy executive director of the AIDS Institute, a non-profit group, said he doesn't believe that the administration in uncaring about HIV/AIDS policy, but harm could come from some of Trump's positions as well as the seeming lack of direction on the issue from the White House.

"It's a mixed bag," Schmid said. "I think the jury is still out and we're still into the first inning of this."

An HHS spokesman told NBC News that all HHS entities remain "firmly committed" to supporting people living with HIV/AIDS through research, funding and various services.

In a proclamation commemorating World AIDS Day Friday, Trump said, "We pray for all those living with HIV, and those who have lost loved ones to AIDS."

"As we remember those who have died and those who are suffering, we commend the immense effort people have made to control and end the HIV/AIDS epidemic," Trump said.

But his statement was denounced by activists for its failure to address the LGBT community, which is disproportionately affected by the crisis, and seen by some as further proof of his administration's indifference. President Barack Obama mentioned the LGBT community in his proclamations, as did Clinton. President George W. Bush's statements on World AIDS Day did not, though Bush created the U.S. President’s Emergency Plan for AIDS Relief, or PEPFAR, in 2003 to address the global HIV/AIDS crisis.

"The White House’s utter failure to take HIV/AIDS seriously is potentially disastrous," Schoettes said in a statement. "Prayers are good, but we need much more than prayers from this White House to solve the HIV/AIDS epidemic in the United States."

Wilson, the Chicago man who relies on Obamacare for his AIDS medications, is still most concerned about what's to come on health care policy.

"Should they get their wish and totally dismantle the health care system in the country, I might have to leave the country," he said.