A Mayo Clinic–led meta-analysis suggests that transfusion of COVID-19 convalescent plasma improves survival in hospitalized, infected patients who have impaired immune systems.
The antibody-rich plasma, donated by COVID-19 survivors, may help prevent the reinfections to which these high-risk patients are susceptible, the researchers said. The study was published yesterday in JAMA Network Open.
On Aug 12, 2022, the team analyzed 3 randomized clinical trials (RCTs), 5 matched-cohort studies, 13 uncontrolled case series, and 125 case-report series on the use of convalescent plasma in immune-impaired COVID-19 patients.
A 37% risk reduction
In the primary meta-analysis of 8 controlled trials involving 469 intervention patients, COVID-19 convalescent plasma was tied to a lower all-cause death rate than observed in 1,305 control patients in a combination of randomized clinical trials and matched-cohort studies (risk ratio [RR], 0.63; 95% confidence interval, 0.50 to 0.79).
In an individual-level analysis of the 125 case reports or case series involving 265 patients, the median time from symptom onset to receipt of convalescent plasma was 17 days, and the median time from hospitalization to plasma therapy was 11 days. Fifty-one of 218 patients (23.4%) received mechanical ventilation, and 31 of 265 (11.6%) died.
The authors noted that interest in convalescent plasma was renewed when monoclonal antibodies, which had been widely used, were found to be ineffective against the new immune-evasive SARS-CoV-2 variants. Since then, several scientific groups have revised their guidelines to recommend convalescent plasma for immune-impaired patients.
“COVID-19 convalescent plasma appears to have maintained clinical efficacy over time with emerging SARS-CoV-2 variants due to heterogeneous, broad spectrum of neutralizing antibodies and widespread availability,” they wrote, “…particularly for patients who are immunocompromised, who are not able to mount a sufficiently protective antibody response against the virus, and who have contraindications or adverse effects from small molecule antivirals.”
COVID-19 convalescent plasma appears to have maintained clinical efficacy over time with emerging SARS-CoV-2 variants.
The authors pointed out that while most studies included in their meta-analysis used convalescent plasma from unvaccinated donors, “it is noteworthy that Vax-Plasma is now widely available from regular donors and retains higher neutralizing antibody titers and efficacy against most SARS-CoV-2 variants.“