(Reuters) – The World Health Organization on Monday was cautious about supporting the use of recovered plasma from COVID-19 patients to treat people who are ill, saying that evidence that it works remains “low quality”, even if the United States emergency authorization for such issued therapies.
PHILO PHOTO: Convalescent plasma of a recovered coronavirus disease (COVID-19) patient is seen at the Central Seattle Donor Center of Bloodworks Northwest during the outbreak in Seattle, Washington, US April 17, 2020. The plasma of recovered patients will be used in an experimental treatment study for current coronavirus patients. REUTERS / Lindsey Wasson / File photo
The so-called convalescent plasma, which has long been used to treat diseases, has emerged as the last political flashpoint in the race to find therapies for COVID-19.
The U.S. Food & Drug Administration (FDA) authorized the use on Sunday after President Donald Trump blamed the agency for experiencing the rollout of vaccines and therapies for political reasons.
The technique involves taking antibody-rich plasma from patients recovering from COVID-19 and giving it to those suffering from severe active infections in hopes that they will recover more quickly.
Soumya Swaminathan, WHO chief scientist, said that only a few clinical trials have produced recoverable plasma results, and the evidence, at least so far, is not convincing enough to support it out of use as experimental therapy. While a few tears have shown some benefit, she said, they were small and their data, so far, unintentional.
“At the moment, it is still evidence of low quality,” Swaminathan told a news conference. “That we recommend that convalescent plasma is still an experimental therapy, it should continue to be evaluated in well-designed randomized clinical trials.”
Evidence is conflicting: One Chinese study showed plasma of people recovering from coronavirus failed to make a difference in patients admitted to hospital, while another, pool analysis showed that it may increase the risk of death lower.
One challenge, Swaminathan added, was the variability of plasma, because it is drawn from many different people, producing a product that is less-standardized than monoclonal antibodies made in the lab.
First adviser to the World Health Organization Bruce Aylward added that apart from the effectiveness of plasma, there were also potential safety risks that needed to be controlled.
“There are a number of side effects,” Aylward said, ranging from mild fever to severe lung wounds or circular overload. “For that reason, the results of clinical trials are extremely important.”
The U.S. National Institutes of Health announced this month that it was donating several million dollars to a convalescent plasma test at midday.
Report by John Miller in Zurich, Stephanie Nebehay in Geneva, Kate Kelland in London; Edited by Jon Boyle and Giles Elgood