09/26/2021 at 3:13 PM CEST
A Spanish investigation led by a team from the Puerta de Hierro de Majadahonda Hospital, in Madrid, and financed by the ISCIII’s COVID Fund, has analyzed the use of plasma from people convalescing from SARS-CoV-2 infection to treat certain patients entered by Covid-19.
The results point to a favorable effect of plasma since it seems to avoid the need for mechanical ventilation and reduces the risk of death in some people who were admitted with the infection in the first week from the onset of symptoms.
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These conclusions, which have just been published in the international journal Journal of Clinical Investigation, arise from a multicenter clinical trial in which 350 patients from 27 Spanish hospitals participated.
The use of plasma from donations from people convalescing from infections used to treat the same infection in other people is not new.
This possible treatment consists of a transfusion to the infected patient with plasma from the blood of people who have passed COVID-19 and have recovered.
From the biological point of view it has its explanation in the ‘transmission of antibodies’ from those people who have recovered from the disease to patients who begin to suffer from it.
To date, the different clinical trials had failed to identify the group of people who could benefit from this treatment. But the now published study identifies patient groups for whom this treatment might be beneficial.
According to the results of the analysis carried out in Spain, the use of convalescent plasma could be useful in patients admitted in the first days after the onset of symptoms and who have not developed antibodies.
In these cases and provided that the plasta is used before they develop serious disease, it avoids the worsening, the need to intubate the patient and, ultimately, reduce their risk of death.
The improvement results appear as early as 14 days after treatment and reach statistical significance at 28 days.
Specifically, treatment reduces the need for mechanical ventilation or death by more than 50% (8.4% of patients in the plasma group in the aforementioned severity categories compared to 17.0% in the control group at 28 days ).
This improvement begins as early as 14 days (11.7% in the treatment group versus 16.4% in the group without plasma).
Cristina Avendaño-Solá and Rafael Duarte, the main authors of the research, consider that the results are important for two reasons.
The first is that it allows us to identify the group of patients in whom the early use of plasma significantly changes the prognosis of the disease.
And secondly, it makes it possible to safely direct the use of this therapeutic alternative, which is neither effective nor recommended for all infected people.
In fact, the researchers point out that plasma should not be used indiscriminately, especially when the probability of serious disease after infection has dropped dramatically after vaccination.
According to the data obtained so far, immunosuppressed patients with difficulties in developing their own immune response after the vaccine or natural infection, and who have a worse prognosis, could benefit from this type of plasma.
With these results, valuable information is added about one of the possible treatments for Covid-19 that have been investigated and debated since the beginning of the pandemic.
The authors recall that, after some initial enthusiasm for the use of plasma, confidence cooled after several studies that found no evidence of efficacy of plasma in patients with advanced Covid.
Characteristics of convalescent plasma
Once confirmed that it is not useful for advanced cases, research and use of plasma is focusing on certain patients in the early stages of the disease.
Another way of study is the characteristics of the plasma that is administered. The research authors explain that current knowledge makes it clear that plasma used as possible therapy it must not come from an indiscriminate collection of convalescent people, and that it is essential to ensure certain characteristics.
For instance, must contain adequate concentrations of neutralizing antibodies, an analysis work that in the study now published has been carried out from the National Center for Microbiology of the ISCIII.
Another interesting feature of plasma is its neutralizing capacity against the variant of the virus that causes the disease in the patient to whom it is administered, if the plasma has been obtained from donors who have just overcome the disease in the same geographic area as the patient.
This possible advantage of plasma extends to new variants that could escape the immunity developed by the population against previous variants, either through vaccination or after natural infection.
With regard to the short-term future of the possible use of plasma from convalescent people, the authors of this work highlight the efforts of the thousands of donors that have made the plasma used in this study, patients and families, as well as the researchers available.
There are various international initiatives, in which the Spanish trial participates, that will pool the data generated by these clinical trials and re-analyze them with the aim of, for example, determining issues such as usefulness in various groups of patients: immunosuppressed people, with poor prognosis markers in terms of their own immune response and in early stages of the disease.