COVID-19 Convalescent Plasma Seems Safe for High-Risk Children

High-titer COVID-19 convalescent plasma seems safe when given to high-risk children, but recipient plasma neutralization titers decline rapidly, according to a study recently published in JCI Insight.

Oren Gordon, M.D., Ph.D., from the Johns Hopkins University School of Medicine in Baltimore, and colleagues prospectively enrolled high-risk children to receive high-titer COVID-19 convalescent plasma. For up to two months after transfusion, the passive transfer of antibodies and endogenous antibody production were serially evaluated.

Overall, 14 high-risk children received high-titer COVID-19 convalescent plasma: nine within five days of symptom onset and five within four days after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure. The researchers found that no serious adverse events related to transfusion were reported. Antibodies to SARS-CoV-2 were transferred to the recipients, but by 14 to 21 days, the titers declined (half-life for spike protein immunoglobulin G, 15.1 days). Donor plasma had significant neutralization capacity; although this was transferred to the recipient, recipient plasma neutralization titers were 6.2 percent of donor titers as early as 30 minutes after transfusion.

"Achieving higher neutralization titer in recipients will require the use of plasma with much higher neutralizing titers, such as that obtained from individuals who had COVID-19 and were subsequently vaccinated," the authors write. "These data suggest that current use of convalescent plasma in high-risk children may only achieve low titers of neutralizing antibody."