Donald Trump has fired the remaining members of his advisory panel on HIV and Aids, abruptly and without full explanation, and drawing accusations that he is retaliating against activists and experts who oppose his healthcare agenda.

The White House said such moves are typical when one administration takes over from another.

The presidential advisory council on HIV and Aids, known as Pacha, is a diverse team of experts from across the US that was set up under Bill Clinton. It volunteers advice to the White House and government agencies on all aspects of HIV and Aids prevention, research, activism and community care and outreach.

Six members of the panel resigned in the summer, protesting against what they saw as a lack of support from the Trump administration. They accused the White House of not caring about the issue.

On Wednesday, the remaining members of the panel received letters informing them they were being terminated. Some had more than a year left on their contracts.

The White House said it was a routine move, a step towards changing the guard from members appointed by Barack Obama. But some panel members were left surprised, bruised and suspicious.

“I had recently been re-sworn in through 2018, so why now?,” said Gabriel Maldonado, one of the fired advisers, who is chief executive of TruEvolution, a California group that works for the elimination of HIV and Aids and justice for lesbian, gay, bisexual and transgender (LGBT) people.

“The timing feels awkward.”

I think we all know there is a hostility that this administration has to people in the LGBTQ community Gabriel Maldonado

Maldonado said he was shocked to receive his termination letter by FedEx courier.

“It feels like retribution,” he told the Guardian. “I’ve criticized the Trump government’s HIV policy … I think we all know broadly that there is a hostility that this administration has to people in the LGBTQ community, particularly [among] those on the evangelical right wing.”

The post of national director of Aids policy has not been filled under Trump. Maldonado said that left a glaring hole in policy work at the top level.

He also said repealing or severely weakening the Affordable Care Act – a Trump promise – would have a disproportionate effect on Aids sufferers and population groups more vulnerable to contracting HIV.

When members of the panel quit last summer Maldonado stayed on, hoping to have a greater effect from inside the administration than outside it.

Donald Trump sent termination letters to the council by FedEx courier. Photograph: Jim Lo Scalzo/EPA

He said he was very concerned by a recent report by the Washington Post that the federal Centers for Disease Control and Prevention (CDC) has been prohibited from using words including fetus, transgender, evidence-based and diversity in policy advice documents. The same report said language about sexual orientation and gay issues was being cut from some health department literature and websites.

“It’s unclear exactly what is happening but it seems to be a foreshadowing of what they are thinking on policy,” Maldonado said.

It is not unusual for a new administration to replace panel members appointed by a predecessor. Obama replaced Pacha members appointed by George W Bush. But Maldonado said it was the way the panel was fired by Trump that gave him pause.

Another dismissed panel member, Emory University public health expert Patrick Sullivan, told the Washington Blade a strong national policy on HIV and Aids was “critical to people’s health and to making new HIV infections rare”.

Trump has proposed deep cuts to budgets for Aids prevention and research domestically and internationally, prompting accusations he is abandoning the cause.

Earlier in the year the president signed an executive order reinstating the policy known as the global gag rule. This removes US aid from groups involved with abortion services in any way. Many such groups help people living with HIV and Aids.

In Congress and then as governor of Indiana, vice-president Mike Pence had a track record of promoting policies designed to thwart LGBTQ rights and opposing federal funding for HIV and Aids support groups.

The administration is expected to pick a replacement Pacha panel. Those terminated were told they can re-apply if they choose. Maldonado said he would not do so.

A statement issued by B Kaye Hayes, executive director of Pacha, said: “The members of Pacha received a letter informing them that the administration was terminating their appointments. They were also thanked for their leadership, dedication and commitment to the effort.

“Changing the makeup of federal advisory committee members is a common occurrence during administration changes.”