Coronavirus: What is convalescent plasma therapy? Things you should know.

With nearly 2.2 million cases already and over 150,000 deaths to infections globally, the world seems to have become very helpless in the face of the Covid-19 pandemic. Scientists are scrambling for vaccines, drugs and other ways that could be used as treatment against novel  With no surety of a definite treatment in sight, doctors around th world are dusting off a century-old treatment for infections: Infusion of blood plasma teeming with immune molecules that might help survivors beat the infection. The top medical research body of India, the Indian Council of Medical Research (ICMR), on April 16 approved a clinical trial for plasma treatment of those seriously ill with Covid-19.

Here’s all you need to know

What is convalescent plasma therapy?

Plasma therapy uses antibodies found in the blood of people who have recovered from an infection (or convalesced), to treat patients who are infected.

How does plasma therapy work against 

In this therapy, blood is drawn from a person who has recovered from the disease and the serum is separated and screened for virus-neutralising antibodies.

When attacked by a pathogen, our immune systems produce antibodies and in this therapy these antibodies from recovered patients are used to treat other sick people.

As the months progress, the world seems still maddeningly short of definitive treatment or vaccine options against COVID-19. However, as the number of people with active COVID-19 infections has increased globally, scientists are “close” to deciding on some promising drug and vaccine candidates and clinical trials are on at multiple centres to test the safety and efficacy of these options. Among the many scientific terms that seem to have entered common parlance with COVID-19 is convalescent plasma. While we may be, in an optimistic scenario, a few weeks or months away from drugs or vaccines, clearly some front-runners have emerged, including remdesivir (originally designed to target the Ebola virus) and convalescent plasma. Convalescent plasma is a time-tested strategy that has worked successfully with several other diseases, and doctors struggling to bring relief to COVID-19 patients have turned towards it — it is blood derived from patients who have recovered from COVID-19 — on the assumption that their body contains antibodies it used to fight the virus.

What is convalescent plasma? How does it work?

As Dr. Michael Joyner, professor, Mayo Clinic, explains on the institution’s website: People who have recovered from COVID-19 have antibodies to the disease in their blood. Doctors call this convalescent plasma. Researchers hope that convalescent plasma can be given to people with severe COVID-19 to boost their ability to fight the virus. The blood — about 800 ml or so — is collected from the donor through the regular withdrawal process, tested for other pathogens, and if safe, the plasma component is extracted and subsequently used for transfusion on to patients. Everyone who has suffered from a disease possibly carries what are called neutralising antibodies that when extracted via plasma and transfused on to others with the infection can help their immune system fight it off. Whether it works or not depends on whether the disease produced a lot of antibodies in people or not, explains Dr. Priya Sampathkumar, infectious diseases consultant and medical director, infection prevention and control, Mayo Clinic, U.S. For some diseases, the body needs more cellular immunity to fight the infection, while for others, the body needs more antibodies. Most diseases, however, require a combination of both these mechanisms, Dr. Sampathkumar points out.