About a month after Donald Trump took office as the 47th US president, almost all grant-review meetings remain suspended at the US National Institutes of Health (NIH), preventing the world’s largest public funder of biomedical research from spending much of its US$47-billion annual budget.

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These review panels are suspended because the Trump administration has barred the agency from taking a key procedural step necessary to schedule them. This has caused an indefinite lapse in funding and left scientists facing difficult decisions about the future of their research programmes.

The Trump administration issued an order on 27 January freezing payment on all federal grants and loans, but lawsuits challenging its legality were filed soon afterwards, putting the order on hold. However, payments are still not going out, because Trump’s team has halted grant-review meetings, exploiting a “loophole” in the process, says Aaron Hoskins, an RNA biochemist at the University of Wisconsin–Madison who has had to reconsider hiring graduate students because of a frozen grant application. “It’s really quite nefarious.”

Some legal scholars say that this ‘back-door’ approach to freezing funding is illegal. That’s because the US Constitution gives Congress, not the president or his team, the power to appropriate funds, says David Super, an administrative-law specialist at Georgetown University Law Center in Washington DC. Blocking “advisory-committee meetings that are legally required to make payments is no different in effect than simply refusing to sign contracts or issue cheques”, he says.

The NIH, which is based in Bethesda, Maryland, did not respond to Nature’s queries about the freeze, its legality or when the freeze would be lifted.

A loophole in the process

To gain approval, NIH research-grant applications are considered in two steps, by two separate panels. The first is a study section, which is a group of independent scientists who convene to score applications. The second is a meeting of the agency’s advisory council, which is a separate group of external and internal scientists and advisers that acts as a final check on an application before a funding decision is made.

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To run either of these grant-review sessions, the agency must post its meeting plans at least 15 days in advance on the Federal Register, which is the official daily publication of the US government. Trump’s team has barred NIH officials from making these posts, according to e-mail correspondence that Nature has obtained. The NIH has posted no notices on the Federal Register since Trump took office; during the same period in 2024, the agency posted more than 150 notices.

According to the e-mail, the Trump administration will, in future, require that these notices be posted at least 35 days before grant-review meetings, instead of the standard 15 in effect previously. This means that, even if these notices were allowed again from today, the earliest date on which a new grant-review meeting could be scheduled is 28 March.

A small number of study sections have convened since Trump took office, but only because a Federal Register notice was posted to schedule them before his inauguration. The continuing cancellation of these meetings has had a snowball effect, and there is now an enormous backlog of applications (see ‘Trend reversal’).

An untenable backlog

Advisory councils at 23 of the NIH’s institutes and centres usually meet only once every four months to discuss grant applications. The first council gatherings for 2025, which were scheduled to be held between late January and early February, were cancelled by the new administration during a ‘communications pause’.

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“As we get more backed up, there will reach a point where it’ll be impossible to do peer review in time for the [second] council meeting date,” says an NIH scientific review officer, who requested anonymity because he is not authorized to speak to the press.