Monoclonal antibodies reduce the risk of hospitalisation 77% in 1,395 patients who had breakthrough COVID-19 infections, found research from the Mayo Clinic in the Journal of Infectious Diseases.
To conduct the retrospective study, researchers compared outcomes of confirmed COVID-19 patients who were fully vaccinated treated with either bamlanivimab, bamlanivimab-etesevimab, or casirivimab-imdevimab, as single infusion from January to August 16, 2021, with those who did not receive treatment.
The average age of breakthrough patients was 54 years. Roughly 10% were cancer patients, and 69.8% had been fully vaccinated with the Pfizer-BioNTech vaccine, a mean 120 days prior to infection.
More than two thirds of the breakthrough infections—71.8%—occurred after June 2021, when the Delta (B1617. 2) variant was the dominant strain in the Midwest, where the study was conducted. The rate of hospitalisation was 2.7% among patients treated with monoclonal antibodies, compared with 10.7% among those who did not receive therapy.
“Since the vast majority of our cohort developed breakthrough COVID-19 during the Delta surge, our finding also provides the clinical correlate to experimental data that suggested that casirivimab-imdevimab retains efficacy against SARS-CoV-2 B.1.617,” the authors said.
Patients with significant comorbidities were most likely to have significant symptoms from breakthrough infections. Patients who had high blood pressure, chronic kidney disease, and cardiovascular disease were at increased risk, the authors said.
Study details
Monoclonal Antibody Treatment of Breakthrough COVID-19 in Fully Vaccinated Individuals with High-Risk Comorbidities
Dennis Bierle, Ravindra Ganesh, Sidna Tulledge-Scheitel, Sara Hanson, Lori Arndt, Caroline Wilker, Raymund Razonable.
Published in the Journal of Infectious Diseases on 16 November 2021
Abstract
Breakthrough COVID-19 may occur in fully vaccinated persons. In this cohort of 1395 persons (mean age, 54.3 years; 60% female; median body mass index, 30.7) who developed breakthrough COVID-19, there were 107 (7.7%) who required hospitalisation by day 28. Hospitalisation was significantly associated with the number of medical comorbidities.
Anti-spike monoclonal antibody treatment was significantly associated with a lower risk of hospitalisation (Odds Ratio: 0.227; 95% confidence interval, 0.128 – 0.403; p<0.001). The number needed to treat (NNT) to prevent one hospitalisation was 225 among the lowest-risk patient group compared to NNT of 4 among those with highest numbers of medical comorbidity.
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CDC: Breakthrough COVID-19 infections mostly rare and mild
Double vaccination cuts breakthrough infection risk substantially — King’s College London
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