What is blood plasma therapy and does it work for Covid-19?

On Sunday evening Donald Trump announced the emergency authorization of convalescent plasma, a method which has been used to treat flu and measles, for Covid-19 patients.

The move comes after the US president expressed frustration at the slow pace of approval for coronavirus treatments, and caused controversy by publicly linking the Food and Drug Administration (FDA) to the “deep state” conspiracy theory.

The press conference on a still uncertain treatment and its timing on the eve of the Republican convention has triggered a lot of commentary and criticism. Here is a quick guide:

What is blood plasma therapy?

When people are sickened with a disease, such as Covid-19, their immune systems generate antibodies to fight back. These antibody proteins are found in blood plasma, the liquid that surrounds blood cells.

Scientists are able to take blood plasma from someone who has had Covid-19 and isolate the antibodies. These antibodies can then be injected into someone sick with the disease, to help combat it until the patient’s immune system generates enough of its own antibodies and ward off the infection.

Does it work for Covid-19?

Blood plasma therapy is among a group of potential therapeutics for Covid-19 that have been undergoing testing in clinical trials. The FDA has said initial trials show it is safe, with a Mayo Clinic study of 35,000 patientsshowing that those who received transfusions within three days of their Covid-19 diagnoses had a seven-day death rate of 8.7%, while the mortality rate of who got it four or more days later was 11.9%.

However, this trial did not include a placebo group for comparison and the therapy lacks any proof of benefit for Covid-19 from large, randomized studies. Dr Anthony Fauci, the White House’s top infectious disease expert, and Dr Francis Collins, the director of the National Institutes of Health, have both reportedly urged the FDA against a rushed approval of plasma therapy due to the weak supporting evidence of its efficacy.

In a memo, an unidentified FDA staffer who reviewed the data said the therapy “meets the ‘may be effective’ criteria” for it to be used on an emergency basis but that further studies are required.

Why has the Trump administration approved this?

The FDA has issued an emergency use authorization for Covid-19 blood plasma therapy under severe pressure from Trump, who over the past week has accused his own federal officials of delaying approval of blood plasma until after the November election and attacked “the deep state, or whoever, over at the FDA” for hindering efforts to test vaccines and therapeutics. No evidence has been provided to back these claims.

Is this pressure from Trump unusual?

The extraordinary pressure from a president to hurry along the approval of therapies while they are still being evaluated, a process that often takes years to undertake, echoes Trump’s enthusiastic backing of hydroxychloroquine, an anti-malarial drug that the FDA also issued an emergency issuance for, only to later withdraw it.

The FDA “need to feel the heat, because the American people are suffering”,according to Mark Meadows, the White House chief of staff.

Trump has repeatedly claimed the coronavirus will simply disappear and has pondered aloud what he considers potential miracle cures, including the injecting of disinfectant, as the US death toll from the pandemic has surged beyond 175,000 people.

Are Trump’s actions dangerous?

Public health experts have said the president has recklessly pushed unproven and potentially dangerous therapies while ignoring the longer-term measures needed to contain the virus, such as mass mask-wearing, cautious reopening of public venues and contact tracing of those infected.