Sweeping layoffs in the federal Health and Human Services department, including shuttering the entire San Francisco branch this week, could have catastrophic consequences for HIV/AIDS services and potentially put at risk longstanding efforts to end the epidemic, public health experts say.

The job cuts began Tuesday, after the Trump administration announced plans last week to slash 10,000 positions across Health and Human Services; the San Francisco office employed 318 people.

On the federal level, several agency leaders were either laid off or forced out of their office this week, including Dr. Jeanne Marrazzo, head of the National Institute of Allergy and Infectious Diseases — the department charged with HIV/AIDS services, which was formerly led by Dr. Anthony Fauci.

Critics of the cuts said they appear to be disproportionately aimed at HIV/AIDS services, and in particular resources for vulnerable communities that are especially at risk of being infected and having poor health outcomes.

But any disruption in HIV services could be disastrous, both for people who are already infected and for the nation’s efforts to end transmission of the disease, critics said.

“San Francisco and the region generally are about to be hit pretty seriously by the process that the HHS reorganization has unleashed,” said Ernest Hopkins, senior strategist and adviser for the San Francisco AIDS Foundation.

“In a place like San Francisco that has been on the cutting edge, to have this kind of disruption — where the federal government, your partner, abruptly steps away — it completely puts everything at risk,” Hopkins said. “San Francisco has done a very good job over the years of backfilling cuts at the federal level for HIV programs. But we’ve never experienced anything of this magnitude.”

The Trump administration plans to dramatically reshape the nation’s public health system, which is run by the Health and Human Services department that oversees the National Institutes of Health, the Centers for Disease Control and Prevention, the Food and Drug Administration and other agencies.

Health and Human Services employs about 82,000 people, so the layoffs happening this week account for an eighth of the total staff. Another 10,000 staff had already left since President Donald Trump took office in January.

But experts in HIV care said they weren’t concerned only about job cuts. Perhaps more worrisome are efforts to dismantle diversity and inclusion programs that are critical for robust public health care, they say. Many diseases, including HIV, disproportionately affect certain communities — often communities of color — and health officials need to be able to focus on those areas.

“This administration has been concerning for HIV since Day One,” said Carl Schmid, founder of the HIV+Hepatitis Policy Institute, a national nonprofit that provides health care. He referred specifically to White House attacks on diversity, equity and inclusion, “and everything we do in HIV is based on disparities, whether you’re gay, Black, Latino.”

Schmid noted that Trump is especially interested in wiping out services for transgender people and immigrants — two groups that also are disproportionately affected by HIV.

“HIV has been a disease of disparities. And so you’ve got to prevent where the virus is, and you’ve got to treat the people who have it, no matter who they are,” Schmid said.

It’s possible, Schmid and other health experts said, that the administration will continue funding services like the Ryan White HIV/AIDS Program, which provides care to half a million people with HIV in the United States. Much of the concern now is simply not knowing which services will remain once the cuts are complete.

“It’s a little bit difficult to draw the clear connection of what is being cut and how it will impact services, because it’s all happening real time right now,” said Chuan Teng, chief executive of PRC, a San Francisco nonprofit that provides services for people with HIV. “Part of the challenge is just the chaos. I don’t know if that’s by design but it feels like it. Just the level of uncertainty alone is causing a lot of issues.”

Though HIV cannot be cured, when infected people are treated with antiviral drugs they cannot spread the disease. So getting people tested and treated is key to ending the epidemic. And that strategy has proven very effective in San Francisco, where new infections are at record low levels.

But experts in HIV care said that the systems in place to prevent spread of the disease are especially vulnerable to interruptions in funding. Stopping HIV requires a multi-faceted approach — including testing, pre-exposure prophylaxis (PrEP) medication regimen for prevention, and care for those who are infected — and impeding any of those efforts can lead to an increase in new cases.

“The progress that we’ve made is still very fragile, and these cuts really put at serious risk these efforts,” said Jorge Reyes Salinas, a spokesperson for Equality California, which advocates for LGBTQ people. “In cities like Los Angeles and San Francisco, agencies are already working with very limited resources and any reduction in funding could mean catastrophe.

“The path to ending the HIV epidemic isn’t automatic. It’s been a long process that we’ve been fighting for years,” Salinas said. “We’re talking about dismantling all of these efforts quickly and reducing decades of hard-won gains.”

Reach Erin Allday: e allday@sfchronicle.co m ; X: @erinallday

Trump’s HHS layoffs in S.F. could be a ‘catastrophe’ for fight against AIDS, experts say