biostudies-literaturePark HSNCATSNCATS NIH HHSNIAID NIH HHSNHLBI NIH HHSState of MarylandMoriah FundNIAIDMental Wellness FoundationHealthnetwork FoundationNHLBIOctapharmaShear Family FoundationBloomberg PhilanthropiesNIGMS NIH HHSDefense Health Agencye178460https://www.ebi.ac.uk/biostudies/studies/S-EPMC11141865biostudies-literatureUnknown9(8)BACKGROUNDCOVID-19 convalescent plasma (CCP) virus-specific antibody levels that translate into recipient posttransfusion antibody levels sufficient to prevent disease progression are not defined.METHODSThis secondary analysis correlated donor and recipient antibody levels to hospitalization risk among unvaccinated, seronegative CCP recipients within the outpatient, double-blind, randomized clinical trial that compared CCP to control plasma. The majority of COVID-19 CCP arm hospitalizations (15/17, 88%) occurred in this unvaccinated, seronegative subgroup. A functional cutoff to delineate recipient high versus low posttransfusion antibody levels was established by 2 methods: (i) analyzing virus neutralization-equivalent anti-Spike receptor-binding domain immunoglobulin G (anti-S-RBD IgG) rJCI insightOutpatient COVID-19 convalescent plasma recipient antibody thresholds correlated to reduced hospitalizations within a randomized trial.PMC11141865R01 AI152078W911QY2090012T32 GM149382U24TR001609-S3U24 TR001609123UL1 TR0014094K23 HL1518265T32 AI102623671K23HL151826NIH3R01AI152078-01S1Huaman MAGebo KANa YBWu JCluzet VCPatel BBlair JELane KArroyo-Curras NRausch WEhrhardt SLee JSPark HSSitaras IBetenbaugh MJPaxton JHOu JOei KCordisco MEKnoll MDCurrier JSKarlen NJabs DARam MCasadevall APekosz AKassaye SGBloch EMSachithanandham JYoon SHanley DFGniadek TJLi MLevine ACMeisenberg BRCaputo CAFord DEOrnelas-Gatdula ENdahiro NShoham SForthal DNSpivak ESShade DMMcBee NAZiman AYin AHammel JSutcliffe CGHammitt LLMosnaim GSJedlicka ACachay ERAbinante MZand MSKlein SLCruser DHeath SLGreenblatt BShapiro JRSingh ALaeyendecker OSullivan DJBaker ORGawad ALBarranta CEby YAnjan SAppel LJShenoy AGBroderick PBRaval JSFernandez REFukuta YYarava APetrini JRCaturegli PMarshall CEGerber JMLau BBaksh SNTobian AAfalseOutpatient COVID-19 convalescent plasma recipient antibody thresholds correlated to reduced hospitalizations within a randomized trial.BACKGROUNDCOVID-19 convalescent plasma (CCP) virus-specific antibody levels that translate into recipient posttransfusion antibody levels sufficient to prevent disease progression are not defined.METHODSThis secondary analysis correlated donor and recipient antibody levels to hospitalization risk among unvaccinated, seronegative CCP recipients within the outpatient, double-blind, randomized clinical trial that compared CCP to control plasma. The majority of COVID-19 CCP arm hospitalizations (15/17, 88%) occurred in this unvaccinated, seronegative subgroup. A functional cutoff to delineate recipient high versus low posttransfusion antibody levels was established by 2 methods: (i) analyzing virus neutralization-equivalent anti-Spike receptor-binding domain immunoglobulin G (anti-S-RBD IgG) r2024-01-01T00:00:00Z2024 Mar2026-04-08T19:51:13.712Z2026-04-08T14:32:06.92ZS-EPMC111418653848353410.1172/jci.insight.178460