COVID-19: Fitness Centers / Antibodies & Future Infection / Monoclonal Antibody Guidance

By Amy Orciari Herman

Edited by Susan Sadoughi, MD, and Richard Saitz, MD, MPH, FACP, DFASAM

Here's a look at some of the latest COVID-19 developments:

Fitness centers: Two articles in MMWR highlight the high risk for COVID-19 transmission at indoor fitness centers. In the first, two thirds of 81 people who attended indoor classes at a Chicago gym during the last week of August 2020 developed COVID-19. Of these cases, three fourths attended classes during their infectious period, including some who were symptomatic. Many said they infrequently wore masks (less than 60% of the time). In the second article, researchers report on 21 COVID-19 cases linked to a fitness instructor at Hawaii exercise facilities. The instructor had taught classes before he developed symptoms. Of note, when the instructor wore a mask for a yoga class, none of the unmasked attendees developed COVID-19. When he did not wear a mask for other classes, the COVID-19 attack rate was as high as 100%. The authors of the first article note that "the increased respiratory exertion that occurs in the enclosed spaces of indoor exercise facilities facilitates transmission of SARS-CoV-2."

Antibodies & future infection: People who are seropositive for SARS-CoV-2 seem at lower risk for future infection — at least for several months — according to a large, retrospective study in JAMA Internal Medicine. Using data from diagnostic laboratories and electronic health records, U.S. researchers studied nearly 3.3 million people who had SARS-CoV-2 antibody tests in 2020. Most were initially seronegative. At 90 days or more of follow-up, 3% of those who were initially seronegative had a positive nucleic acid amplification test for SARS-CoV-2 — versus just 0.3% of those who were initially seropositive. Of note, in a small subset of patients who underwent repeat antibody testing, 18% of those who were initially seropositive became negative after 90 days' follow-up. The researchers say their findings suggest that "seropositivity is associated with protection from infection" but caution that "the duration of protection is unknown."

Monoclonal antibody guidance: The National Institutes of Health now recommends the combination of bamlanivimab (700 mg) plus etesevimab (1400 mg) for the treatment of outpatients with mild-to-moderate COVID-19 who are at high risk for clinical progression. The FDA granted an emergency use authorization to the monoclonal antibody combination earlier this month. High-risk patients include those with a BMI at or above 35, diabetes, chronic kidney disease, or an immunocompromising condition; adults 65 and older; and those aged 12-17 years with sickle cell disease or congenital heart disease (see full-list of high-risk criteria in the guidance linked below). The NIH recommends against use of bamlanivimab plus etesevimab in patients hospitalized for COVID-19.