ELLSWORTH — In an effort to identify possible convalescent plasma donors and as an incentive to get blood donations up after they plummeted this spring, the American Red Cross is testing blood donations for COVID-19 antibodies, giving those who donate confidential results in a week to 10 days.
The Red Cross rolled out antibody testing in mid-June after months of stay-at-home orders and physical distancing resulted in canceled blood drives and a “severe blood shortage,” according to a press release from the organization in mid-March.
Drives usually held at colleges, workplaces and schools were canceled, resulting in 86,000 fewer donations, according to the press release. Volunteer donors are the only source of blood for patients needing transfusions after car accidents, for surgery or for cancer treatments.
Blood is perishable and can’t be stockpiled, so it has to be constantly replenished. Red blood cells have to be used within 42 days of donations and platelets within five days. To meet the needs of the nation’s patients, the Red Cross needs to collect nearly 13,000 blood donations and 2,600 platelet donations every day.
In Ellsworth, the organization has a goal of 90 donations per month. Donations dropped off sharply in February, according to figures provided by the Red Cross, to 37 percent of the monthly goal (from 73 percent in January). Numbers were up in March, nearly hitting the 90-donation target, and down in April, but have rebounded significantly since May, when the Ellsworth Rotary Club began volunteering.
“The Ellsworth Blood Drive program has become one of the most productive programs in the state,” said Market Manager Thomas Hinman in an email last week.
The Red Cross in Ellsworth has exceeded its target every month since May, with a peak of 110 donations in July. The organization has sought to assure volunteers that it’s safe to give blood, with donors spaced 6 feet apart and extra precautions in place.
Donors may learn whether they have been exposed to COVID-19 in the past.
Antibodies develop in the body in response to infections, helping guard against future exposure. They exist in plasma, the liquid aspect of blood that’s mostly water and what’s left over after everything else (red and white blood cells, platelets and other cellular components) is removed.
Convalescent (a fancy word for recovered) plasma has been used for more than a century as a treatment for certain diseases, a therapy known as “passive immunity” (as opposed to “active immunity,” when you develop your own antibodies).
Hospitals have treated more than 70,000 people hospitalized with coronavirus with convalescent plasma, according to a press release from the Food and Drug Administration (FDA). The agency gave emergency approval for expanded use of plasma to help hospitalized coronavirus patients on Aug. 23 but scrambled after experts questioned a statistic cited by President Trump and two top health officials that the treatment reduced deaths by 35 percent.
Researchers have said that convalescent plasma does show promise, but the data released from the Mayo Clinic study cited by President Trump show a more nuanced picture: among a group of roughly 35,000 patients who were given plasma within three days of diagnosis, the death rate was about 22 percent after 30 days, compared with a 27 percent death rate among patients who were given plasma four or more days after diagnosis. Researchers also found that patients given plasma with higher levels of antibodies appear to be more likely to survive.
And those who do test positive for the antibodies that respond to COVID-19 should be cautious about interpreting the results, scientists warn.
The most widely available tests, for “binding antibodies,” are designed to see whether a person has developed antibodies in response to a COVID-19 infection, but don’t indicate how extensive or effective that immune response is, according to the Mayo Clinic.
More sensitive tests done after a person is tested for binding antibodies look for “neutralizing antibodies,” a subgroup that can inactivate the virus. The presence of those antibodies can tell clinicians more about how long immunity to COVID-19 might last.
Testing positive for antibodies, in other words, doesn’t mean you should start walking around maskless and throwing parties.
In guidelines published earlier this month, experts from the Infectious Diseases Society of America (IDSA) warned that many antibody tests are inaccurate and cannot determine if someone is immune. Scientists are also still unsure how long immunity lasts, and the fewer cases of the virus in your area, the more likely you are to have a false-positive test. A positive antibody test, the guidelines note, “cannot inform decisions to discontinue physical distancing or lessen the use of personal protective equipment.”
But large-scale antibody testing can be useful for figuring out how prevalent the virus is in the population and for “tracking the course” of the pandemic in the community, the guidelines note.