In less than four months since the beginning of the epidemic, the number of confirmed cases of Covid-19 has already exceeded 2.5 million – and no vaccines or drugs are currently available or expected in the near future for coronavirus infection. In the absence of effective treatment, doctors around the world, including in Russia, are trying to save seriously ill patients by transfusing blood plasma from people who have already recovered. Moscow has even introduced extra payments for such donors. However, the effectiveness of such treatment has not been proven, clinical trials of the therapy are just beginning, and medical experts sometimes make recommendations for its use that directly contradict each other.
The BBC’s Russian service looks at why doctors are taking risks with experimental therapies, how justified such experiments are, and whether blood transfusions can help fight the pandemic. In theory, plasma treatment seems simple and logical. Cured patients have beaten the disease precisely because their immune systems have learned to fight the infection by producing antibodies – special proteins that neutralize the virus. These antibodies (immunoglobulins) are found in the blood, or more specifically, in its liquid component, plasma.
And in theory, if they are taken from a healthy donor and given to a sick patient, they should fight the virus in the new host’s body in the same way. This method has long been used in medicine to prevent viral infections. Perhaps the best known example is rabies vaccination, which is administered after being bitten by a wild animal. The bitten person receives an injection of immune serum from horse blood, whose antibodies neutralize the virus and prevent the development of the deadly disease (the probability of a fatal outcome in case of infection is almost 100%). The prospect of such a successful treatment for coronavirus infection sounds very appealing.
The method is relatively inexpensive, and in theory there should be no shortage of donors: around the world, hospitals have discharged nearly 700,000 people who have recovered from Covid-19 (about 4,000 in Russia). “This is the only way we can affect the coronavirus, by directly blocking it,” said Pavel Madonov, BBC Doctor of Medical Sciences, Head of the Department of Pharmacology, Clinical Pharmacology and Evidence-Based Medicine at NGMU. At the same time, he emphasized that in the case of Covid-19, plasma transfusions should be used with extreme caution.
In Moscow, three patients have already recovered after plasma transfusions from donors previously treated with Covid-19, said the deputy mayor of the Russian capital, Anastasia Rakova, on Tuesday. According to her, two of them were discharged from the hospital 10 days after the procedure and the third after two weeks. “All of them are currently in good condition. We hope that the number of such recovered cases will continue to increase and that this treatment method will help us cope with the coronavirus pandemic,” Rakova said. The study of the use of plasma in recovered persons is being conducted in St. Petersburg. It is not known whether such plans exist in other regions. In Moscow, plasma for transfusion is accepted at two locations: the N.V. Sklifosovsky Emergency Medical Research Institute and the City Clinical Hospital No. 52, where BBC confirmed that in several cases, patients with Covid-19 were treated with plasma transfusion from recovered individuals.
We explain quickly, simply and clearly what happened, why it matters and what will happen next. The number of episodes should remain the same. End of story. Podcast Advertising. The Moscow government has issued a resolution stating that blood donors with antibodies to Covid-19 will receive 1250 rubles (approximately $16) for every 150 ml of plasma. It is possible to donate from 300 to 600 ml at a time. Before becoming a donor, former patients must provide a medical certificate stating that they have recovered from Covid-19. Donors must also have negative tests for HIV, hepatitis B and C, a complete blood count, data on biochemical blood tests and tests for the presence of specific antibodies to SARS-CoV-2. The Moscow City Hall website states that donor plasma transfusion is “one of the most effective methods of treating coronavirus in the absence of a vaccine”. After the procedure, patients with coronavirus feel better and no side effects have been observed.
However, the medical community is reluctant to announce the discovery of a cure-all. “In my opinion, despite its apparent effectiveness and relative simplicity, the therapeutic effect of this drug may be somewhat exaggerated,” said Ratchik Grigoryants, a doctor of medical sciences at the Department of Blood Transfusion of the Bakulev Scientific Center for Cardiovascular Surgery, according to the BBC. All medical prescriptions are based on evidence-based medicine. The efficacy and safety of a particular drug or procedure must be proven in clinical trials – and in the case of the new coronavirus, there are currently none. Any publications on the subject in scientific journals are nothing more than attempts by doctors to share their experiences with a few patients.
In order to comply with all the necessary formalities, it is necessary to recruit a sufficient number of critically ill patients with Covid-19 who are already connected to a ventilator, randomize them into two groups and transfuse one group with donor plasma containing antibodies, while the other group receives a placebo solution. Only by comparing the outcomes of the two groups is it possible to draw a scientific conclusion about the efficacy and safety of such a treatment. This is the only accepted method. However, in the conditions of a pandemic of a new virus, such experiments are not possible. It is possible to give the control group of seriously ill patients a placebo instead of real plasma, depriving them of their only chance of recovery.
The only acceptable option is when the patient is already in intensive care, but his condition continues to deteriorate. Then it is possible to try to save the hopeless patient with an experimental method that is not officially recommended. This is exactly what was done in 2003 when the atypical pneumonia SARS outbreak began, and many lives were saved. Later, the practice of transfusion was approved by the WHO as a last resort and was used during the Ebola and Middle East Respiratory Syndrome (MERS) epidemics. According to Grigoryants, it makes sense to transfuse plasma specifically in the last critical stage of the disease, when “the effect of transfusing pure plasma – with all its inherent fundamental advantages – far outweighs the effect of experimental antiviral treatment on patients. “This is exactly what puzzles me when I see a lot of propaganda promoting the use of antiviral plasma. I am convinced that the problem of the shortage of blood factors and components is much more important today than the experimental use of immunized plasma,” he says.
At the same time, Grigoryants notes that widespread use of plasma therapy is unlikely anyway. Only 30% of people with the disease have a sufficient concentration of antibodies in their blood, and not all of them are willing to become donors. On the other hand, Pavel Madonov believes that ideally – after clinical trials – antiviral plasma will be needed not for critically ill patients, but for those whose disease is just beginning to develop. According to him, it makes sense to fight the virus when it has just entered the bloodstream from the respiratory organs. “The virus is dangerous only because of complications,” he explains. “The fact of its presence in the body is not so dangerous, but it causes specific complications: intense inflammation in the lung tissue, which leads to acute respiratory failure. As they would say in court, the virus is absolutely indirectly responsible – it didn’t do it, the patient’s body did it itself in response to its attack”. When a patient develops respiratory failure, it is too late to fight the virus,” says the professor. However, the main hope is still the development of a special vaccine against the virus. “The vaccine is the body’s training for defense. It is preventive: as soon as an unwelcome guest appears, he is immediately caught, put in a car and taken to the police. And antibodies are the work that has already been done. It is no wonder that in medicine this method of treatment is called the therapy of despair,” the scientist points out.