The FDA announced Sunday it will grant an emergency authorization (EUA) of convalescent plasma as a treatment for the coronavirus, one day after President Trump accused the agency of slow-walking the development of vaccines and therapeutics to hurt him politically.

The state of play: The authorization for plasma, which is safe but not yet proven to work on COVID-19, had been on hold after federal health officials intervened with the FDA last week and argued that the current data on the effectiveness of the treatment was too weak, The New York Times reported.

• Former FDA commissioner Scott Gottlieb said on Sunday that plasma is "probably weakly beneficial," but that health officials "wanted to see more rigorous data to ground this decision."
• It's unlikely to be the major "breakthrough" that White House press secretary Kayleigh McEnany touted in a tweet previewing the announcement on Saturday, according to Gottlieb and other health experts.

What they're saying:

How it works: The therapeutic, which has been undergoing testing in clinical trials, involves infusions of antibody-rich plasma from people who have recovered from the virus.

• The idea is to kick-start an infected patient's immune system so that they can fight off COVID-19 until they're able to generate their own antibodies, according to Stat News.
• A study of 35,000 people who received plasma treatment through the Mayo Clinic found that the therapeutic has had some impact on reducing mortality among hospitalized coronavirus patients.
• However, the study was not peer-reviewed and did not include a control group, making the data difficult to interpret.

The big picture: White House chief of staff Mark Meadows defended Trump's attacks on the FDA on Sunday, claiming on Fox News that "deep state" bureaucrats don't understand the "urgency" of the moment.

• "We are facing unprecedented times, which require unprecedented action," Meadows said. "This president is right to call it out, and I can tell you that the announcement that's coming today should have been made several weeks ago."

Between the lines: Trump administration officials told Axios' Alayna Treene in July that the president was planning to change his messaging to heavily promote vaccines and therapeutics, including by personally announcing developments at press briefings.

• Officials believe that's the fastest way to restore confidence in Trump and avoid having the election be a referendum on his handling of the pandemic.
• Trump's plasma announcement comes one day before the start of the Republican National Convention.

The bottom line: The EUA — which is not the same as a full FDA approval — will make the treatment easier to obtain in some settings, but won't help advance the type of randomized trial needed to fully determine its effectiveness.