In a real-world cohort study of 2,571 people, the use of monoclonal antibodies to treat COVID-19 within 2 days of receiving a positive COVID-19 test reduced the risk of hospitalization or death by 39% percent compared with nonrecipients. Persons with immunocompromising conditions benefited even more, with a 55% reduction in risk of hospitalization or death.
Researchers conducted a hypothetical pragmatic randomized trial of patients treated with monoclonal antibodies matched with data from 5,135 patients with COVID-19 who were eligible for monoclonal antibodies but did not receive them. “The risk for hospitalization or death at 28 days was 4.6% in 2,571 treated patients and 7.6% in 5,135 nontreated control patients (risk ratio [RR], 0.61 [95% CI, 0.50 to 0.74]),” the authors report. “In sensitivity analyses, the corresponding RRs for 1- and 3-day treatment grace periods were 0.59 and 0.49, respectively. In subgroup analyses, those receiving mAbs when the Alpha and Delta variants were presumed to be predominant had estimated RRs of 0.55 and 0.53, respectively, compared with 0.71 for the Omicron variant period. Relative risk estimates for individual mAb products all suggested lower risk for hospitalization or death. Among immunocompromised patients, the RR was 0.45 (CI, 0.28 to 0.71).”