Antibody anxieties

Kathy Nyman, a 59-year-old nurse from Rochester, Minn., and her husband, a physician, both received COVID-19 diagnoses at the end of May. They recovered, and after testing negative, donated plasma twice at Mayo Clinic to support research into a treatment doctors hope will help patients recover from the disease faster.

Nyman said she is “really grateful that God brought us through it” and wants to do what she can to support research on the virus.

At the end of August, the U.S. Food and Drug Administration gave hospitals easier access to so-called convalescent plasma from people like the Nymans who have recovered from COVID-19. They transfuse the plasma into hospitalized patients in hopes the antibodies in the plasma will help fight the disease. The FDA is still studying the safety and efficacy of the treatments, but some early findings look positive.

Patients treated with convalescent plasma in two small studies seemed to show better oxygen levels and less organ failure, and they came off ventilators sooner, Medscape reported. And a study posted on the website MedRxiv but not yet peer-reviewed showed improved survival for nonintubated patients who received convalescent plasma—though not for intubated patients.

Scientists working to understand how antibodies help recovered patients avoid catching the virus again have turned up mixed information.

One study, posted Aug. 15 on MedRxiv, a pre-print server for health sciences, found recovered individuals’ immunity to the coronavirus increased over three months following the first symptoms. The study is under review by the journal Nature. A second pre-print study on Aug. 16 indicated immunity might last for several months. And a preliminary report in Cell on Aug. 11 found people who had mild or asymptomatic cases, as well as their family members, showed strong immune responses. The finding suggests infection or natural exposure might prevent severe COVID-19 cases. All of those studies await peer review.

“This is exactly what you would hope for,” Marion Pepper, an immunologist at the University of Washington, told The New York Times.

But reports surfaced in recent weeks of three people who apparently got COVID-19 a second time. In all three cases, genome sequencing of viral samples showed significant genetic differences between the virus associated with the first infection and the second. That likely means the patients caught a different strain of the virus the second time.

In the first two cases, one involving a man from Hong Kong and the other an elderly patient with a compromised immune system in Denmark, the second infection produced mild to no symptoms.

The third case involved a 25-year-old man who experienced mild symptoms the first time but required hospitalization and oxygen support the second, the University of Nevada, Reno, School of Medicine said on Aug. 27. But Mark Pandori, one of the researchers, stressed that “this is a singular finding” and doesn’t mean reinfection is common.