Plasma taken from the blood of recovered COVID-19 patients given to sick people with the disease does not reduce their chances of becoming seriously ill or dying, according to new research from a study in India.
The research, which involved more than 400 people who were hospitalized with COVID-19, investigated convalescent plasma as a treatment for people with moderate illness. The results, published in the medical journal BMJ on Friday, concluded that “convalescent plasma showed limited efficacy.”
Findings from one of the first clinical trials to investigate the efficacy of convalescent plasma are a setback for a treatment that US President Donald Trump touted in August as a “historic breakthrough.”
The United States and India, which are battling the world’s worst COVID-19 outbreaks, have authorized convalescent plasma for emergency use.
The United States and India have authorized the use of convalescent plasma in the treatment of COVID-19. [File: Lindsey Wasson/Reuters]
Other countries, including the UK, have been collecting donated plasma so that it can be widely implemented if it is shown to be an effective treatment.
“The … trial was able to show a small effect on how quickly patients were able to shed the virus, but this was not enough to improve their recovery from the disease,” said Simon Clarke, an expert in cell microbiology at the University of Reading.
“In simple terms, there were no clinical benefits for patients.”
With no cure or vaccine, countries have struggled to find ways to moderate the effect of COVID-19.
Rigorous study
The convalescent plasma technique (taking antibodies from recovered patients and using them to treat people who still have the disease) was first tested against diphtheria in 1892 and was shown to help speed recovery from Ebola and acute respiratory syndrome severe (SARS, which is caused by the same family of pathogens as the new coronavirus).
The new study, funded by the Indian Council for Medical Research, enrolled 464 adult patients, with an average age of 52, between April and July and randomly divided them into two groups.
A control group of 229 received the best normal standard of hospital care, while 235 people received two convalescent plasma transfusions and the best standard of hospital care.
After seven days, the use of convalescent plasma appeared to improve some symptoms, such as shortness of breath and fatigue, the researchers said, and led to higher rates of something known as “negative conversion,” a sign that the virus is being neutralized. by antibodies. .
But this did not translate into a reduction in deaths or progression to severe disease within 28 days.
After that period, 44 (19 percent) of the participants in the plasma group and 41 (18 percent) in the control group progressed to severe disease or died from any cause.
When they restricted the comparison to patients who received plasma with detectable levels of antibodies, the results were the same, the authors said.
The trial “was a rigorous randomized controlled study on a topic of enormous global importance,” said public health scientist Elizabeth Pathak in a separate comment also published in the BMJ.
Levels, time
The researchers said future studies could explore using only plasma with high levels of neutralizing antibodies to see if this could be more effective.
The results were greeted with caution by a spokesperson for the UK’s National Health Service, which is also in the process of conducting large randomized control trials of convalescent plasma.
Whole blood samples are placed in a centrifuge to separate plasma for antibody testing in the US A new study suggests that convalescent plasma is not effective as a treatment for COVID-19 [File: Lindsey Wasson/Reuters]The NHS blood and transplant department official said the Indian trial had used donations with antibody levels six to ten times lower than in the UK.
“There is other promising evidence that convalescent plasma transfusions with high levels of antibodies could improve patient outcomes,” the spokesperson told AFP news agency, adding that the results of trials with these higher levels antibody tests “should provide clear answers.”
The point at which a patient receives the plasma could also be important, according to some researchers.
Ian Jones, a professor of virology, also at the University of Reading, says plasma is more likely to work if it is given soon after someone contracts COVID-19.
He urged these and other researchers to continue to conduct convalescent plasma assays in newly diagnosed patients.
“We do not yet have enough early stage disease treatments to prevent severe disease and until this becomes an option, avoiding infection with the virus remains the key message,” he said.
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