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BackgroundMonoclonal antibody and antiviral treatments for COVID-19 disease remain largely unavailable worldwide, and existing monoclonal antibodies may be less active against circulating omicron variants. Although treatment with COVID-19 convalescent plasma (CCP) is promising, randomized clinical trials (RCTs) among outpatients have shown mixed results. MethodsWe conducted an individual participant data meta-analysis from all outpatient CCP RCTs to assess the overall risk reduction for all-cause hospitalizations by day 28 in all participants who had transfusion initiated. Relevant trials were identified by searching MEDLINE, Embase, MedRxiv, WHO, Cochrane Library, and Web of Science from January 2020 to September 2022. ResultsFive included studies from four countries enrolled and transfused 2,620 adult patients. Comorbidities were present in 1,795 (69%). The anti-Spike or virus neutralizing antibody titer range across all trials was broad. 160 (12.2%) of 1315 control patients were hospitalized, versus 111 (8.5%) of 1305 CCP-treated patients, yielding a 3.7% (95%CI: 1.3%-6.0%; p=.001) ARR and 30.1% RRR for all-cause hospitalization. The effect size was greatest in those with both early transfusion and high titer with a 7.6% ARR (95%CI: 4.0%-11.1%; p=.0001) accompanied by at 51.4% RRR. No significant reduction in hospitalization was seen with treatment > 5 days after symptom onset or in those receiving CCP with antibody titers below the median titer. ConclusionsAmong outpatients with COVID-19, treatment with CCP reduced the rate of all-cause hospitalization. CCP may be most effective when given within 5 days of symptom onset and when antibody titer is higher. Key PointsWhile the outpatient COVID-19 randomized controlled trial meta-analysis indicated heterogeneity in participant risk factors and convalescent plasma, the combined CCP efficacy for reducing hospitalization was significant, improving with transfusion within 5 days of symptom onset and high antibody neutralization levels.
RESUMO
BackgroundTherapies to interrupt progression of early COVID-19 remain elusive. Among them, convalescent plasma in hospitalized patients was unsuccessful, perhaps because antibody should be administered earlier. We advanced plasma infusions to the first 72 hours of symptoms to arrest COVID-19 progression. MethodsA randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against SARS-CoV2 in elderly subjects within 72 hours of mild COVID-19 symptoms. The primary endpoint was severe respiratory disease defined as a respiratory rate [≥]30 and/or an O2 sat<93% in room air. The study was interrupted at 76% of its projected sample size, because cases in the region decreased considerably and steady enrollment of study subjects became virtually impossible. Results160 patients underwent randomization. In the intention-to-treat analysis (ITT), 13/80(16.2%) patients receiving plasma vs. 25/80(31.2%) receiving placebo experienced severe respiratory disease [RR(95%CI)= 0.52(0.29,0.94); p=0.026)] with an RRR=48%. A modified ITT analysis, excluding six subjects who experienced the primary endpoint before infusion, showed a larger effect size [RR(95%CI) = 0.40(0.20, 0.81), p=0.007]. High- and low-titer donor analyses, based on a median IgG titer=1:3,200, evidenced a dose-dependent response with an RRR=73.3% for recipients of high-titer plasma (p=0.016) and a number needed to treat (NNT)=4.4. All secondary endpoints exhibited trends towards protection. No solicited adverse events were observed. ConclusionsEarly administration of high-titer convalescent plasma against SARS-CoV2 to mildly ill infected seniors reduced COVID-19 progression. This safe, inexpensive, outpatient intervention facilitates access to treatment from industrialized to LMIC, can decompress demands on hospitals, and may contribute to save lives. Funded by The Bill & Melinda Gates Foundation and The Fundacion INFANT Pandemic Fund. Registered in the Direccion de Sangre y Medicina Transfusional del Ministerio de Salud (PAEPCC19), Plataforma PRIISA (1421), and clinicaltrials.gov (NCT04479163). All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organization for the submitted work; RL, GPM, DW and FPP are investigators in a phase 3 SARS CoV2 trial from Pfizer; no other relationships or activities that could appear to have influenced the submitted work.
