OBJECTIVE: To evaluate the efficacy and safety of antiviral antibody therapies 
and blood products for the treatment of novel coronavirus disease 2019 
(covid-19).
DESIGN: Living systematic review and network meta-analysis, with pairwise 
meta-analysis for outcomes with insufficient data.
DATA SOURCES: WHO covid-19 database, a comprehensive multilingual source of 
global covid-19 literature, and six Chinese databases (up to 21 July 2021).
STUDY SELECTION: Trials randomising people with suspected, probable, or 
confirmed covid-19 to antiviral antibody therapies, blood products, or standard 
care or placebo. Paired reviewers determined eligibility of trials independently 
and in duplicate.
METHODS: After duplicate data abstraction, we performed random effects bayesian 
meta-analysis, including network meta-analysis for outcomes with sufficient 
data. We assessed risk of bias using a modification of the Cochrane risk of bias 
2.0 tool. The certainty of the evidence was assessed using the grading of 
recommendations assessment, development, and evaluation (GRADE) approach. We 
meta-analysed interventions with ≥100 patients randomised or ≥20 events per 
treatment arm.
RESULTS: As of 21 July 2021, we identified 47 trials evaluating convalescent 
plasma (21 trials), intravenous immunoglobulin (IVIg) (5 trials), umbilical cord 
mesenchymal stem cells (5 trials), bamlanivimab (4 trials), 
casirivimab-imdevimab (4 trials), bamlanivimab-etesevimab (2 trials), control 
plasma (2 trials), peripheral blood non-haematopoietic enriched stem cells (2 
trials), sotrovimab (1 trial), anti-SARS-CoV-2 IVIg (1 trial), therapeutic 
plasma exchange (1 trial), XAV-19 polyclonal antibody (1 trial), CT-P59 
monoclonal antibody (1 trial) and INM005 polyclonal antibody (1 trial) for the 
treatment of covid-19. Patients with non-severe disease randomised to antiviral 
monoclonal antibodies had lower risk of hospitalisation than those who received 
placebo: casirivimab-imdevimab (odds ratio (OR) 0.29 (95% CI 0.17 to 0.47); risk 
difference (RD) -4.2%; moderate certainty), bamlanivimab (OR 0.24 (0.06 to 
0.86); RD -4.1%; low certainty), bamlanivimab-etesevimab (OR 0.31 (0.11 to 
0.81); RD -3.8%; low certainty), and sotrovimab (OR 0.17 (0.04 to 0.57); RD 
-4.8%; low certainty). They did not have an important impact on any other 
outcome. There was no notable difference between monoclonal antibodies. No other 
intervention had any meaningful effect on any outcome in patients with 
non-severe covid-19. No intervention, including antiviral antibodies, had an 
important impact on any outcome in patients with severe or critical covid-19, 
except casirivimab-imdevimab, which may reduce mortality in patients who are 
seronegative.
CONCLUSION: In patients with non-severe covid-19, casirivimab-imdevimab probably 
reduces hospitalisation; bamlanivimab-etesevimab, bamlanivimab, and sotrovimab 
may reduce hospitalisation. Convalescent plasma, IVIg, and other antibody and 
cellular interventions may not confer any meaningful benefit.
SYSTEMATIC REVIEW REGISTRATION: This review was not registered. The protocol 
established a priori is included as a data supplement.
FUNDING: This study was supported by the Canadian Institutes of Health Research 
(grant CIHR- IRSC:0579001321).
READERS' NOTE: This article is a living systematic review that will be updated 
to reflect emerging evidence. Interim updates and additional study data will be 
posted on our website (www.covid19lnma.com).