One study says hyperimmune plasma is not effective against coronavirus in severe patients

According to a new Argentine study, hyperimmune plasma would not give significant advantages to patients with severe forms of Covid

(Image: Pixabay) What so far seemed to be a useful tool to give some more chances to patients affected by forms serious Covid-19 could prove to be a chimera. A new study, just published in the New England Journal of Medicine, found no significant benefits in administering hyperimmune plasma. Unlike the observational studies known so far, this survey was carried out with a randomized controlled approach, precisely with the aim of comparing the effects of the therapy with respect to a control group. Does this really mean that we are deluded?

The study, called Plasmar, has the explicit objective of seeing clearly on the therapy based on hyperimmune plasma, the one obtained from Covid-19 patients who have made it and who is rich in antibodies that fight Sars-Cov-2. To do this, researchers recruited 333 patients with a diagnosis of Covid confirmed by Rt-Pcr, pneumonia evident on radiographs and one or more other severity criteria such as a saturation less than 93%. The median age was 62, mostly male, and 65% of them had a previous medical condition.

Patients were divided into two groups: 228 received hyperimmune plasma therapy, while 105 were treated with a placebo. However, all were able to receive treatment with antiviral agents and / or glucocorticoids. Researchers were thus able to compare the effects of treatment by assessing the status of patients 30 days after the infusion of hyperimmune plasma or placebo. according to a six-step staircase that goes from discharge to death.

Unfortunately they found no significant differences. The overall mortality, in fact, was 10.96% in the group that received the hyperimmune plasma and 11.43% in the placebo group. "A risk difference - the authors write in the article - of -0.46 percentage points". The frequency of adverse effects and serious adverse effects did not increase in the treatment group. What was different was the antibody titer of the patients, which was higher in the patients under treatment two days after the infusion.

"In our study we have ensured that over 95% of the plasma units of convalescents transfused had a total anti-Sars-Cov-2 antibody titer of at least 1: 800 and that the volume of plasma infused had a correction factor based on the weight of the participant ”, reads the article. "This finding is in contrast to the results of a number of non-randomized trials which state that convalescent plasma is of substantial benefit, and illustrates the importance of randomized and controlled trials, especially in the context of a pandemic." Researchers, however, admit that the survey has limitations and that the data will have to fit into a wider range of randomized controlled trials.

Median patient recruitment time, for example, is been 8 days from the onset of symptoms. Only 39 received the hyperimmune plasma treatment within 72 (ideal time frame to have the best results according to other observational investigations) and without obtaining any advantages, indeed. The number, however, is too small to draw conclusions.

The Argentine study also does not demonstrate that hyperimmune plasma treatment cannot be effective in other categories of patients, perhaps those with a milder form of Covid-19.