(HealthDay)—Administration of convalescent plasma seems safe and results in improvement in clinical status for patients with severe or life-threatening COVID-19, according to a study not yet peer reviewed and posted on medRxiv.org.

For the study, Eric Salazar, M.D., Ph.D., from Houston Methodist Hospital, and colleagues enrolled 25 patients with severe or life-threatening COVID-19 from March 28 to April 14, 2020. Convalescent plasma was obtained from donors with confirmed severe acute respiratory syndrome coronavirus 2 who had been symptom-free for 14 days and was then transfused into patients.

All patients were receiving supportive care at baseline, including anti-inflammatory and antiviral treatments; all patients were on oxygen support. The researchers found that nine patients had at least a 1-point improvement in the clinical scale at day 7 after transfusion with ; seven of these patients were discharged. Nineteen (76 percent) had at least a 1-point improvement in clinical status by day 14, and 11 were discharged. There were no adverse events observed as a result of plasma transfusion. On sequencing, no strain genotype-disease severity correlation was identified.

"Convalescent plasma therapy has been administered on the front lines during emergencies, and we and others recognize the need for controlled to determine its therapeutic efficacy," the authors write.