Gabriel Maldonado, the chief executive of TruEvolution, an advocacy group for lesbian, gay, bisexual and transgender people and an H.I.V. and AIDS services organization, who was among those dismissed, said federal officials could have removed him and his colleagues when Mr. Trump was inaugurated or at one of the two meetings the council held this year.
During those meetings, he said the council had voiced concerns over the Trump administration’s position on the Affordable Care Act, among other issues.
Six members announced their departure in June. Writing in Newsweek, one of the former members, Scott A. Schoettes, who is counsel and H.I.V. project director at Lambda Legal, said that “the Trump administration has no strategy to address the ongoing H.I.V./AIDS epidemic, seeks zero input from experts to formulate H.I.V. policy, and — most concerning — pushes legislation that will harm people living with H.I.V. and halt or reverse important gains made in the fight against this disease.”
Mr. Maldonado said he also found it strange that Mr. Trump issued an executive order in September continuing 32 advisory committees — including the council on H.I.V. and AIDS — whose operating authorities had been set to expire. That would have been an appropriate time to relieve the remaining members of their appointments, he said.
David Kilmnick, the president of the LGBT Network, criticized the dismissals. “We have finally made significant progress in trying to end the epidemic once and for all and the irrational and immature moves by Trump will only set us back,” he said in a statement.
Patrick Sullivan, a professor of epidemiology at Emory University in Atlanta who studies H.I.V. prevention and was among the council members terminated, said the move came as a surprise, but added that he thought it was a “positive sign” that Mr. Trump had signed the executive order continuing the council.
He urged the administration to formally affirm the National H.I.V./AIDS Strategy drawn up during the Obama administration, which he said would help ensure “we’re all pulling in the same direction toward a common goal.”
The strategy’s basic premise is that everyone old enough to be sexually active should be tested for H.I.V. regularly, either as part of routine care or through special efforts. Everyone who tests positive should be put on triple-therapy treatment immediately and kept on it for life.
It also recommends that anyone at high risk — gay men with many sexual partners, people who inject drugs, people whose regular partner is infected, and so on — should be offered pre-exposure prophylaxis, a daily antiretroviral pill that, if taken faithfully, reduces the chances of infection almost to zero.
The domestic strategy on the disease is overseen by the director of National AIDS Policy, a White House post created by Mr. Clinton in 1993. The advisory council helps with that strategy.
But since 1993 — around the time that antiretroviral triple-therapy cocktails turned H.I.V. infection from a death sentence into a dangerous but manageable illness — the White House job has been fairly low profile.
Eleven people have held the post since 1993, none for more than three years. Mr. Trump has left the job vacant since January.