During the pandemic, convalescent plasma was widely used as a potential treatment for COVID-19. But a new systematic review of 48 randomized trials involving over 24,500 people delivers a clear verdict: for people with moderate to severe COVID-19, convalescent plasma does not reduce the risk of death or the need for a ventilator. It also doesn't speed up hospital discharge or improve quality of life.
The review, which compared convalescent plasma to placebo or standard care, found little to no impact on key outcomes. The risk of serious side effects was slightly higher in the plasma group, though the evidence is moderate certainty. For people with mild COVID-19, the picture is less clear. The evidence is uncertain for most outcomes, including death and hospital admission. One comparison suggested that convalescent plasma might reduce hospital admissions or death, but this finding is based on very low certainty evidence.
It's important to note that the review included trials with varying quality and patient populations. The results are most reliable for moderate to severe disease, where the evidence is stronger. For mild disease, more research is needed to draw firm conclusions.