South Bay hospitals are trying plasma transfusions

Santa Clara County hospitals have begun transfusing plasma from recovered COVID19 patients into people who are critically ill from the coronavirus in hopes the fluid will save lives.

The effort in one of the California counties hardest hit by the coronavirus is part of a national study from the Mayo Clinic to determine whether plasma — a liquid component of blood — can help people who are critically ill from COVID19. Because the plasma comes from people who have recovered from the virus, it contains antibodies to the coronavirus and may help others recover from the disease.

Antibodies are proteins made by the immune system to fight infections caused by viruses, bacteria or other pathogens. Researchers don’t yet know whether patients who have recovered from COVID19 become immune to getting it again, as happens for some diseases.

“Infections like the new coronavirus are dangerous because we do not have antibodies against them. We hope to learn if supplying antibodies can save lives,” said Dr. Dayani NuallesPercy, the lead investigator of the study at the Santa Clara Valley Medical Center. “Given the lack of natural immunity and the lack of a vaccine, plasma therapy may help to provide the body what it needs to fight the infection.”

The study comes at a time when treatment options for the coronavirus are few. Nationally, 2,228 sites are participating in the study to see if it works and, so far, 9,374 people have been infused with convalescent plasma. In Santa Clara County, where the study began on April 9, five patients have so far received the treatment. In addition to Santa Clara Valley Medical Center, O’Connor Hospital and St. Louise Regional Hospital are participating in the study.

The goals of the study are to see whether plasma from recovered patients can help patients breathe, keep them off ventilators, prevent them from having to go to the ICU, and ultimately, keep them alive.

A separate but similar study is being conducted at UCSF and San Francisco General Hospital.

Blood is composed of white and red blood cells, platelets and plasma. Everything but the plasma is filtered out, NuallesPercy said.

“It’s just a component of your blood,” she said. “The blood centers separate it and they only keep, in this particular case, the portion of blood that has the antibodies. And that’s what we infuse.”

Transfusing the plasma through an IV takes about an hour. To qualify for the study, COVID19 patients must be over 18 and in the hospital with severe complications.

“The hope is to help people by providing antibodies early on … they could fight the infection faster and don’t get as sick,” NuallesPercy said.

Using convalescent plasma to transfuse antibodies into an ill patient is different from the antibody testing that is occuring globally.

Antibody testing is intended to determine whether a person has previously been infected with the coronavirus, in which case antibodies would be present. But such tests have high error rates: Negative results do not rule out the coronavirus and positive results may be false.

The Mayo Clinic study is focusing instead on a potential treatment.

“This (study) is looking at people who have recovered, and it’s not based on widespread testing to see if someone has antibodies,” said John Swartzberg, a UC Berkeley infectious disease expert. “The operative word is convalescent. If you’ve gotten over a case of COVID, you have got something in your blood that might really help somebody else.”

The trial is a promising step forward in studying the virus that can’t be contained yet by a single drug, said Robert Siegel, an infectious disease expert at Stanford.

For one thing, it will help scientists determine what role antibodies will play in controlling the infection. In some cases, like measles, antibodies are very effective in conferring immunity. But in other cases, like HIV, people can have lots of antibodies, but it doesn’t help control the infection, Siegel said.

“This trial will not only be important in terms of a possible therapy, it may also tell us something about the nature of the infection,” Siegel said. “It will help us understand what parts of the immune systems are most important in controlling the virus.”

Access to convalescent plasma is largely dependent on community participation — people donating at their local Red Cross blood banks or Stanford.

“We call it liquid gold because it’s so valuable and we treat each one with reverence,” said Dr. Peter ChinHong, UCSF infectious disease specialist. “When it comes, it’s like, wow, someone actually donated this and we are so lucky to able to get it.”

ChinHong is also leading a study on convalescent plasma and said a total of 10 patients at UCSF and San Francisco General Hospital have been infused. The criteria for each patient is similar to the work being done by the Mayo Clinic — the plasma is reserved for the sickest patients, but in ChinHong’s case, also those who are immunocompromised.

Of the 10 patients who have received the treatment, none have gotten sicker, ChinHong said. The next step in using convalescent plasma will be to determine when to administer it — early in the diagnosis or when a patient is at their sickest and heading to intensive care.

“We think it’s safe and it probably does work, but we need to know in COVID19 specifically when it works the best,” ChinHong said.