COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

Treatment Devasenapathy N, Ye Z, Loeb M, et al. Efficacy and safety of convalescent plasma for severe COVID-19 based on evidence in other severe respiratory viral infections: a systematic review and meta-analysis. CMAJ. 2020 Jul 6;192(27):E745-E755. doi: 10.1503/cmaj.200642. Epub 2020 May 22.

BACKGROUND: The safety and efficacy of convalescent plasma in severe coronavirus disease 2019 (COVID-19) remain uncertain. To support a guideline on COVID-19 management, we conducted a systematic review and meta-analysis of convalescent plasma in COVID-19 and other severe respiratory viral infections.

METHODS: In March 2020, we searched international and Chinese biomedical literature databases, clinical trial registries and prepublication sources for randomized controlled trials (RCTs) and nonrandomized studies comparing patients receiving and not receiving convalescent plasma. We included patients with acute coronavirus, influenza and Ebola virus infections. We conducted a meta-analysis using random-effects models and assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS: Of 1099 unique records, 6 studies were eligible, and none of these included patients with COVID-19. One nonrandomized study (n = 40) on convalescent plasma in severe acute respiratory syndrome coronavirus (SARS-CoV) provided uninformative results regarding mortality (relative risk [RR] 0.10, 95% confidence interval [CI] CI 0.01 to 1.70). Pooled estimates from 4 RCTs on influenza (n = 572) showed no convincing effects on deaths (4 RCTs, RR 0.94, 95% CI 0.49 to 1.81), complete recovery (2 RCTs, odds ratio 1.04, 95% CI 0.69 to 1.64) or length of stay (3 RCTs, mean difference -1.62, 95% CI -3.82 to 0.58, d). The quality of evidence was very low for all efficacy outcomes. Convalescent plasma caused few or no serious adverse events in influenza RCTs (RR 0.85, 95% CI 0.56 to 1.29, low-quality evidence).

INTERPRETATION: Studies of non-COVID-19 severe respiratory viral infections provide indirect, very low-quality evidence that raises the possibility that convalescent plasma has minimal or no benefit in the treatment of COVID-19 and low-quality evidence that it does not cause serious adverse events.

Discipline / Specialty Area Score
Public Health
Hospital Doctor/Hospitalists
Internal Medicine
Family Medicine (FM)/General Practice (GP)
General Internal Medicine-Primary Care(US)
Intensivist/Critical Care
Comments from MORE raters

General Internal Medicine-Primary Care(US) rater

Important negative-ish study that is similar to: "Don't use hydroxychloroquine, you idiot!"

Intensivist/Critical Care rater

A well done systematic review, but the evidence base is too underdeveloped for this article to be practice-changing or immediately relevant to COVID-19 practitioners. None of the identified trials addressed COVID specifically, and all had several limitations. RCTs are coming that examine this intervention! I would wait for these.

Intensivist/Critical Care rater

Low-quality meta-analysis due to low-quality studies included in it. The review is trying to extrapolate data on the use of convalescent plasma for treatment of COVID-19 from studies investigating convalescent plasma for other respiratory viruses, but the studies and data just aren't out there. They end up including 6 studies, 4 of which are RCTs; all of the RCTs are in influenza. Overall, the article is just not very informative with regard to the effects of convalescent plasma in COVID-19.

Intensivist/Critical Care rater

More careful analysis of using convalescent serum to treat severe viral illness. Using relatively slim data from studies of SARS, influenza, and Ebola, there was little evidence of benefit or harm. Whether this applies to Covid-19 or not remains to be seen.

Internal Medicine rater

We are coming up with many studies on potential treatments. We need more robust RCTs to truly see if there are benefits to these treatments.

Public Health rater

It's general information that is poorly related to my specialty, but rather interesting due to the current importance of the COVID-19 pandemic.

Public Health rater

Good evidence synthesis that highlights our uncertainties and warrants caution in the use of this therapeutic for COVID-19.