A ban on acquiring fetal tissue for research has derailed promising research in the fight against HIV/AIDS.

The Trump administration has quietly put a stop to scientists employed by the U.S. National Institutes of Health (NIH) acquiring new human fetal tissue for experiments, leading to a shutdown of vital HIV/AIDS research.

The change came back in September, without any public announcement, and is part of a broad review of all fetal tissue research funded by the federal government, Science Insider reports.

The Department of Health and Human Services (HHS) announced that same month that a contract between the Food and Drug Administration and Advanced Bioscience Resources, Inc., a non-profit based in Alameda, California, had been terminated.

“HHS was not sufficiently assured that the contract included the appropriate protections applicable to fetal tissue research or met all other procurement requirements,” the statement read.

“HHS has initiated a comprehensive review of all research involving fetal tissue to ensure consistency with statutes and regulations governing such research, and to ensure the adequacy of procedures and oversight of this research in light of the serious regulatory, moral, and ethical considerations involved,” it continued. “Finally, HHS is continuing to review whether adequate alternatives exist to the use of human fetal tissue in HHS funded research and will ensure that efforts to develop such alternatives are funded and accelerated.”

A spokesperson for NIH confirmed to Science Insider that the agency had put a “pause” in place pending the outcome of the review.

That pause hit two laboratories, according to NIH officials: One operated by the National Eye Institute, and one by the National Institute of Allergy and Infectious Diseases (NIAID). The latter, NIAID’s Rocky Mountain Laboratories in Hamilton, Montana, was in the middle of promising research in search of an HIV cure.

Researchers were in the process of researching an antibody that had shown impressive results in lab dish studies, leading them to believe it might prevent HIV from establishing reservoirs in the human body.

“This effectively stops all of our research to discover a cure for HIV,” Kim Hasenkrug, one of the researchers on the project, wrote in an email passing on the news that HHS had put the ban in place to his colleague, Warner Greene, director of the Gladstone Center for HIV Cure Research in San Francisco.

Greene noted that the lost time imposed by the ban has already proven detrimental.

“If we were given the green light right now (to resume fetal tissue collection), it would probably take us a year to get back in the position we were in when the ban was put in place,” he said.

Thomas Packard, a postdoctoral student of Greene’s who was also involved in the study, called the government’s change in policy “a travesty for the outlook for HIV research.”

“Blocking this significantly hurts our chances of finding an HIV cure,” he added.

Fears remain that the policy will be expanded outward to also include universities that receive NIH funding.

“It would shut my lab down if we were not able to use fetal tissues,” said Jerome Zack, a virologist who studies HIV at UC Los Angeles.

NIH emailed an additional statement to Science Insider after the story ran, saying the pause was “an action NIH thought was prudent given the examination of these procurements. Research with tissue already on hand could proceed, and NIH leaders asked to be notified by intramural investigators if new procurement would be necessary. NIH leadership was not informed that new procurement was necessary for the study you reference in your story. We are looking into why this did not occur.”

Fetal tissue is obtained from elective abortions, and has long been opposed by anti-abortion groups and the religious right.

The issue gained further spotlight after deceptively edited videos claimed to show Planned Parenthood officials inappropriately looking to sell fetal body parts. Investigations have found that claim to be fraudulent.

An effort to prevent people from using Medicare for pregnancy-related health services at Planned Parenthood that rose out of the backlash has been struck down by the courts, with the Supreme Court deciding not to take up the case and leave the lower court ruling in favor of the group stand.