Blood plasma of recovered coronavirus patients helps save severely ill and may be a key solution, study shows
COVID-19 is currently a big threat to global health. However, no specific vaccine or treatments are presently available. The key to managing the COVID-19 pandemic could lie with those that are able to fight it and have recovered. Doctors, who conducted a pilot study, have found evidence that seriously ill coronavirus patients can benefit from blood plasma collected from people who have recovered from the disease.
In the study, doctors from China gave a single 200ml dose of “convalescent plasma” to 10 severely ill patients. They found that the patients showed improvement in symptoms shortly after treatment and the virus levels in their bodies dropped rapidly. The patients did not experience any severe adverse effects. Within three days, the doctors saw improvements in the patients’ symptoms, which had ranged from shortness of breath and chest pains to fever and coughs.
Six days after receiving the infusion, the COVID-19 virus was undetectable in seven of the 10 patients. “Of note is that SARS-CoV-2 RNA was decreased to an undetectable level in three patients on day 2, three patients on day 3, and one patient on day 6 after CP therapy,” says the team.
The results, says the team, suggests potential therapeutic effect and low risk in the treatment of severe COVID-19 patients. “One dose of CP with a high concentration of neutralizing antibodies can rapidly reduce the viral load and tends to improve clinical outcomes. The optimal dose and treatment time point, as well as the definite clinical benefits of CP therapy, need to be further investigated in randomized clinical studies. These results indicate that convalescent plasma (CP) can serve as a promising rescue option for severe COVID-19, while the randomized trial is warranted,” says the study published in the Proceedings of the National Academy of Sciences (PNAS).
Known as convalescent plasma therapy, the treatment has been around for over 100 years and was used during the 1918 Spanish flu pandemic. It uses donated blood plasma from patients who have recovered from the infection. The reason: plasma from someone who has recovered from COVID-19 contains antibodies made by the immune system and used to kill the virus. This antibody-rich plasma is then transfused into someone infected with the virus in the hopes that antibodies from the recovered person can help the person who is sick by killing the virus the next time it attacks.
Blood plasma is the largest part of the blood, making up for more than half (about 55%) of its overall content. When separated from the rest of the blood, plasma is a light yellow liquid, explains a University of Rochester Medical Center article.
“The approach involves giving patients an infusion of antibody-rich plasma from people who have recovered from an infection with SARS-CoV-2, the virus that causes COVID-19. The treatment is based on the function of antibodies, proteins created by the immune system that combat invaders to the body in a variety of ways,” says a Mayo Clinic blog.
During more recent global outbreaks, researchers tested convalescent plasma in small clinical studies and found it had positive effects against coronaviruses that caused severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), as well as against H1N1 influenza. “However, the very same approach turned out not to be effective against Ebola, a filovirus,” says Mayo Clinic.
According to researchers of the current study, the results suggest that the inflammation and overreaction of the immune system were alleviated by antibodies contained in convalescent plasma.
A previous study, published in JAMA, also describes positive results with the same treatment in five critically ill patients with COVID-19 and acute respiratory distress syndrome (ARDS). The condition of all five patients in the study -- who were on mechanical ventilation -- improved after treatment with plasma. The analysis shows ARDS resolved in four patients at 12 days after transfusion, and three patients were taken off the ventilator within 2 weeks of treatment. Of the 5 patients, 3 have been discharged from the hospital, and 2 are in stable condition at 37 days after transfusion, says the March 27 report.
“Administration of convalescent plasma containing neutralizing antibody was followed by an improvement in clinical status. These preliminary findings raise the possibility that convalescent plasma transfusion may be helpful in the treatment of critically ill patients with COVID-19 and ARDS, but this approach requires evaluation in randomized clinical trials,” says the study.
Meanwhile, the US Food and Drug Administration (FDA) has also approved this treatment for coronavirus patients. “Although promising, convalescent plasma has not yet been shown to be effective in COVID-19. It is therefore important to determine through clinical trials, before routinely administering convalescent plasma to patients with COVID-19, that it is safe and effective to do so,” says a statement.
Subsequently, Houston Methodist became the first academic medical center in the US to transfuse donated plasma from a recovered COVID-19 patient into a critically ill patient.
According to an article in Science News, at least 11 patients critically ill with COVID-19 at hospitals in New York City and Houston are the first in the US to receive convalescent plasma.
Writing in the Washington Post, Dr Faheem Younus -- chief quality officer and chief of infectious diseases at the University of Maryland Upper Chesapeake Health -- says that every crisis can present an opportunity. “Right now, we have the opportunity to study convalescent plasma therapy in robust clinical trials. If they work, the treatment could be the bridge the world needs between now and the day we have an effective COVID-19 vaccine,” he says.