One of the more promising potential therapies in the war against the coronavirus is the use of plasma from people recovered from the virus. Convalescent plasma — the liquid part of blood — is rich in antibodies. Although the treatment is early in the experimental stage, early reports indicate that injecting those antibodies into people with Covid-19 might give their immune system a much-needed head start, boosting their ability to fight off the virus, preventing the illness from becoming more severe and perhaps hastening their recovery.
This kind of therapy, called passive immunity, has been around for more than a century. Doctors employed it against the 1918 flu and against polio and measles before vaccines for those diseases were developed.
Scores of convalescent plasma clinical trials are taking place in the U.S. and around the world, comparing people with Covid-19 who receive the plasma to patients who don’t. The U.S. Food and Drug Administration (FDA) has also approved an “expanded access” program in which people can receive plasma outside of studies if they’ve been admitted to an acute care facility and consent to the treatment. More than 19,000 people have received plasma under that program, and early data suggests that the treatment is safe. Whether it’s effective against Covid-19 remains to be seen.
More than any substance, plasma exemplifies the promise and perils of modern medicine. The tea-colored liquid was first separated from blood more than a century ago. Today it serves as raw material for an international pharmaceutical industry that’s worth $20 billion and growing. Every year plasma companies in the U.S. collect more than 38 million pints for processing into more than 50 therapeutic agents, including antibodies, clotting factors, and other useful proteins. They also pay people to obtain it. Most other countries don’t allow such arrangements, but it’s always been the norm in the U.S. As such, we’ve become the biggest player of the plasma trade.
Plasma is easily contaminated by bacteria, and if it’s processed improperly it can kill…