Expert: Antibody response can start to fade in as little as 30 days


Preliminary data from a study out of the University of Missouri has found that the antibody response to COVID-19 can start to fade in as little as 30 days.

Dr. Mark Daniels is an Associate Professor of Molecular Microbiology and Immunology at the university and one of the authors of the study. He told KCBS Radio’s “Ask An Expert” segment Friday about some of the study’s early findings.

They enrolled 3,500 participants, mainly students, and sampled the blood of both known COVID patients and others for antibodies.

“We see some very diverse sets of responses. A lot of patients that have had no symptoms and are surprised about the fact that they have antibodies. We have a number of patients that had very mild symptoms and are rather surprised by the fact that they don’t have antibodies,” he said.

While the study is still in progress, Dr. Daniels said that patients who experience no symptoms or only mild symptoms may not have a lasting antibody response.

“They have a low titer of antibodies that comes early and then fades over time, and sometimes between as early as 30 days and as late as 90 days they can lose their antibody responses.”

Dr. Daniels said this study and others have demonstrated that people who have a more severe infection also develop a stronger antibody response.

What is not known is how this can impact a patient’s chances of becoming infected with the virus for a second time.

“That’s the million-dollar question,” said Dr. Daniels. It is not clear what level of immune response is needed to protect a person from becoming re-infected.

While there have been documented cases of patients falling sick a second time, these cases are still relatively rare.