Plain language summary Is plasma from the blood of people who have recovered from COVID‐19 an effective treatment for other people with COVID‐19? Key messages • We are very confident that plasma from the blood of people who have recovered from COVID‐19 (convalescent plasma) has no benefits for the treatment of people with moderate to severe COVID‐19. • Convalescent plasma may have little to no benefit for treating people with mild COVID‐19. • We found49 ongoing studies and 33 finished studies with unpublished results. We will update our review with evidence from these studies as soon as possible. New evidence may answer our remaining questions, especially for people with mild COVID‐19 or who have no symptoms. What is convalescent plasma? The body produces antibodies as one of its defences against infection. Antibodies are found in part of the blood called plasma. Plasma from people who have recovered from the COVID‐19 virus contains COVID‐19 antibodies, and it can be used to make convalescent plasma, which is plasma that contains these antibodies. Convalescent plasma has been used successfully to treat some viruses. This treatment (given by a drip or injection) is generally well‐tolerated, but can cause unwanted effects. What did we want to find out? We wanted to find out whether convalescent plasma is an effective treatment for people with confirmed COVID‐19. We looked at: • deaths from any cause after treatment with convalescent plasma; • worsening of patients’ condition, measured by the number of people who needed support from a ventilator (a machine that helps people breathe if they cannot breathe on their own) or died; and improvement of patients’ condition, measured by participants discharged from hospital; • quality of life; and • unwanted effects. What did we do? We searched for studies that investigated convalescent plasma to treat people with COVID‐19. Studies could take place anywhere in the world and include people of any age, gender or ethnicity, with mild, moderate or severe COVID‐19. Where possible we pooled (added up) the studies’ results to analyse them. We rated our confidence in the evidence, based on factors such as study methods and sizes. What did we find? We found 33 studies with 24,861 participants that investigated convalescent plasma. Among these, 29 studies included people with moderate to severe COVID‐19 and four studies included people with mild COVID‐19. Studies mainly took place in hospitals, in countries all over the world. The following findings apply to convalescent plasma compared with placebo (the same treatment but with no active ingredients) or standard care. People with moderate to severe COVID‐19 • Convalescent plasma makes no difference to deaths from any cause at up to 28 days after treatment, about 225 in 1000 people died, compared to 220 in 1000 people who had been given convalescent plasma (21 studies, 19,021 people). • Convalescent plasma makes little to no difference to needing invasive mechanical ventilation or dying . About 287 in 1000 people needed invasive mechanical ventilation support or died, compared to 296 in 1000 people given convalescent plasma (6 studies, 14,477 people). It makes no difference to participants being discharged from hospital. About 665 in 1000 people were discharged from hospital, compared to 665 in 1000 people given convalescent plasma (6 studies, 12,721 people). • Convalescent plasma probably makes no difference to serious unwanted effects, about 118 in 1000 people may be at risk to have serious unwanted effects compared to 133 in 1000 people given convalescent plasma (6 studies, 4901 people). • Convalescent plasma may result in no difference in quality of life (1 study, 483 people). People with mild COVID‐19 • Convalescent plasma may result in no difference to deaths from any cause up to 28 days after treatment. About 22 in 1000 people given placebo or standard care died, compared to 9 in 1000 people given convalescent plasma (2 studies, 536 people). • Convalescent plasma may result in no difference to admission to hospital or death within 28 days after treatment. About 112 in 1000 people given placebo or standard care were admitted to hospital or died, compared to 117 in 1000 people given convalescent plasma (1 study, 376 people). • Convalescent plasma may result in no difference in the time until COVID‐19 symptoms resolved (1 study, 376 people). • Convalescent plasma may result in no difference to serious unwanted effects . What are the limitations of the evidence? • We are very confident in the evidence for deaths from any cause, and worsening and improvement of patients’ condition in people with moderate to severe COVID‐19, as the results are consistent and are from many high‐quality studies. • Our confidence in the other evidence for people with moderate and severe, and mild COVID‐19 is still limited, as we could not identify enough consistent results from a lot of studies. • We still have little evidence on quality of life and for people with mild disease, and none for people without COVID‐19 symptoms. How up to date is this evidence? This is the fifth version of our review. The evidence is up to date to 03 March 2022.
【저자키워드】 COVID-19, SARS-CoV-2, immunoglobulins, humans, COVID-19 serotherapy, Virus diseases, COVID-19/therapy,