The Association for the Advancement of Blood and Biotherapies (AABB) has released clinical practice guidelines for the appropriate use of COVID-19 convalescent plasma (CCP) in hospital and outpatient settings. Based on two living systematic reviews of randomized controlled trials (RCTs), the guidelines provide five specific recommendations for treating patients with COVID-19 and suggest that CCP is most effective when transfused with high neutralizing titers to infected patients early after symptom onset. The guidelines are published in Annals of Internal Medicine.

COVID-19 convalescent plasma (CCP) has emerged as a potential treatment of COVID-19. However, meta-analysis data and recommendations are limited. A team lead by AABB’s Clinical Transfusion Medicine committee studied published research to inform the guidelines. The two living systematic reviews of RCTs evaluating CCP from 1 January 2019 to 26 January 2022 comprised 33 RCTs assessing 21,916 participants.

Based on the data, the AABB recommends that non-hospitalized patients at high risk for disease progression should have CCP transfusion in addition to the usual standard of care.

The AABB also recommends against CCP transfusion in hospitalized patients with moderate or severe disease but says that CCP transfusion should be added to usual standard of care for those who do not have SARS CoV-2 antibodies detected at admission and for those with preexisting immunosuppression.

The AABB recommends against prophylactic CCP transfusion for uninfected persons with close contact exposure to a person with COVID-19.

The AABB summarized their findings with a good clinical practice statement: CCP is most effective when transfused with high neutralizing titers early after symptom onset.

Researchers summarized results using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method. Recommendations were made under the assumption that patients would highly value avoiding risks for disease progression, morbidity, and mortality from COVID-19. Thus, when the data suggested that there was limited harm from CCP transfusions and that there was benefit to CCP, the panel was prepared to make recommendations for CCP.

The authors say there are several advantages of CCP. While SARS-CoV-2 evolves and new variants of concern (VOCs) emerge that may evade monoclonal antibodies, high-titer CCP continues to be effective. CCP is also relatively easy to collect, making it a less expensive therapeutic option than other passive antibody therapies.