Convalescent plasma is currently being used in the treatment of COVID-19. Recommendations regarding use convalescent plasma in COVID-19 requires systematic summaries of available evidence. We searched the databases Medline, Embase, Cochrane CENTRAL, Epistomonikos, Medrxiv and Biorxiv. Title/abstract screening, full text screening and data abstraction were carried out in duplicate by two reviewers. Pooled effect sizes and 95% confidence intervals were calculated using random effects meta-analysis. GRADE tool was used to rate the certainty of evidence. Twenty two studies were found eligible for inclusion: nine randomized controlled trials and thirteen cohort studies. Low certainty evidence from eight RCTs showed inconclusive effects of convalescent plasma on mortality at 28 days (OR 0.85, 95% CI 0.61 to 1.18). Low certainty evidence from thirteen cohort studies showed a reduction in mortality at 28 days (OR 0.66, 95% CI 0.53 to 0.82). The pooled OR for clinical improvement was 1.07 (95% CI 0.86 to 1.34) representing low certainty evidence. Evidence from three RCTs showed inconclusive effect of CP on the need for mechanical ventilation (OR 1.20, 95% CI 0.72 to 1.98). Four cohort studies reporting unadjusted estimates suggested a reduction in the need for mechanical ventilation with convalescent plasma (OR 0.80 95% CI 0.71 to 0.91, low certainty). Pooled estimates from 2 RCTs showed inconclusive effects of convalescent plasma on the proportion of patients with nondetectable levels of virus in nasopharyngeal specimens on day 3 (OR 3.62, 95% CI 0.43, 30.49, very low-quality evidence). The present review reports uncertain estimates on the efficacy of convalescent plasma in the treatment of COVID-19. There is low certainty evidence of a possible reduction in mortality and mechanical ventilation, a faster viral clearance and the absence of any serious adverse events. However, its efficacy for these outcomes requires evidence from good quality and adequately powered randomized controlled trials.

恢复期血浆目前用于治疗 COVID-19。关于在 COVID-19 中使用恢复期血浆的建议需要对现有证据进行系统总结。我们检索了数据库 Medline、Embase、Cochrane CENTRAL、Epistomonikos、Medrxiv 和 Biorxiv。标题/摘要筛选、全文筛选和数据摘要由两名评审员重复进行。使用随机效应荟萃分析计算汇总效应大小和 95% 置信区间。GRADE 工具用于评估证据的确定性。有 22 项研究符合纳入条件：9 项随机对照试验和 13 项队列研究。八项随机对照试验的低质量证据表明，恢复期血浆对 28 天死亡率的影响尚不确定（OR 0.85，95% CI 0.61 至 1.18）。13 项队列研究的低质量证据显示 28 天死亡率降低（OR 0.66，95% CI 0.53 至 0.82）。临床改善的汇总 OR 为 1.07（95% CI 0.86 至 1.34），代表低确定性证据。三项随机对照试验的证据表明，CP 对机械通气需求的影响尚无定论（OR 1.20，95% CI 0.72 至 1.98）。四项队列研究报告未经调整的估计值，表明恢复期血浆机械通气的需求减少（OR 0.80 95% CI 0.71 至 0.91，低确定性）。两项随机对照试验的汇总估计显示，恢复期血浆对第 3 天鼻咽标本中病毒水平未检出的患者比例的影响尚不确定（OR 3.62，95% CI 0.43、30.49，证据质量极低）。本综述报告了对恢复期血浆治疗 COVID-19 疗效的不确定估计。低确定性证据表明，死亡率和机械通气可能会降低，病毒清除速度会更快，并且不会出现任何严重的不良事件。然而，其对这些结果的功效需要来自高质量和充分有力的随机对照试验的证据。