Convalescent plasma for people with COVID-19: a living systematic review.

BACKGROUND: Convalescent plasma may reduce mortality in patients with viral respiratory diseases, and is being investigated as a potential therapy for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of this intervention is required. OBJECTIVES: To assess the effectiveness and safety of convalescent plasma transfusion in the treatment of people with COVID-19; and to maintain the currency of the evidence using a living systematic review approach. SEARCH METHODS: To identify completed and ongoing studies, we searched the World Health Organization (WHO) COVID-19 Global literature on coronavirus disease Research Database, MEDLINE, Embase, Cochrane COVID-19 Study Register, and the Epistemonikos COVID-19 L*OVE Platform. We searched monthly until 03 March 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) evaluating convalescent plasma for COVID-19, irrespective of disease severity, age, gender or ethnicity. We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)), as well as studies evaluating standard immunoglobulin. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methodology. To assess bias in included studies we used RoB 2. We used the GRADE approach to rate the certainty of evidence for the following outcomes: all-cause mortality at up to day 28, worsening and improvement of clinical status (for individuals with moderate to severe disease), hospital admission or death, COVID-19 symptoms resolution (for individuals with mild disease), quality of life, grade 3 or 4 adverse events, and serious adverse events. MAIN RESULTS: In this fourth review update version, we included 33 RCTs with 24,861 participants, of whom 11,432 received convalescent plasma. Of these, nine studies are single-centre studies and 24 are multi-centre studies. Fourteen studies took place in America, eight in Europe, three in South-East Asia, two in Africa, two in western Pacific and three in eastern Mediterranean regions and one in multiple regions. We identified a further 49 ongoing studies evaluating convalescent plasma, and 33 studies reporting as being completed. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease 29 RCTs investigated the use of convalescent plasma for 22,728 participants with moderate to severe disease. 23 RCTs with 22,020 participants compared convalescent plasma to placebo or standard care alone, five compared to standard plasma and one compared to human immunoglobulin. We evaluate subgroups on detection of antibodies detection, symptom onset, country income groups and several co-morbidities in the full text. Convalescent plasma versus placebo or standard care alone Convalescent plasma does not reduce all-cause mortality at up to day 28 (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.92 to 1.03; 220 per 1000; 21 RCTs, 19,021 participants; high-certainty evidence). It has little to no impact on need for invasive mechanical ventilation, or death (RR 1.03, 95% CI 0.97 to 1.11; 296 per 1000; 6 RCTs, 14,477 participants; high-certainty evidence) and has no impact on whether participants are discharged from hospital (RR 1.00, 95% CI 0.97 to 1.02; 665 per 1000; 6 RCTs, 12,721 participants; high-certainty evidence). Convalescent plasma may have little to no impact on quality of life (MD 1.00, 95% CI -2.14 to 4.14; 1 RCT, 483 participants; low-certainty evidence). Convalescent plasma may have little to no impact on the risk of grades 3 and 4 adverse events (RR 1.17, 95% CI 0.96 to 1.42; 212 per 1000; 6 RCTs, 2392 participants; low-certainty evidence). It has probably little to no effect on the risk of serious adverse events (RR 1.14, 95% CI 0.91 to 1.44; 135 per 1000; 6 RCTs, 3901 participants; moderate-certainty evidence). Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces or increases all-cause mortality at up to day 28 (RR 0.73, 95% CI 0.45 to 1.19; 129 per 1000; 4 RCTs, 484 participants; very low-certainty evidence). We are uncertain whether convalescent plasma reduces or increases the need for invasive mechanical ventilation, or death (RR 5.59, 95% CI 0.29 to 108.38; 311 per 1000; 1 study, 34 participants; very low-certainty evidence) and whether it reduces or increases the risk of serious adverse events (RR 0.80, 95% CI 0.55 to 1.15; 236 per 1000; 3 RCTs, 327 participants; very low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus human immunoglobulin Convalescent plasma may have little to no effect on all-cause mortality at up to day 28 (RR 1.07, 95% CI 0.76 to 1.50; 464 per 1000; 1 study, 190 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and mild disease We identified two RCTs reporting on 536 participants, comparing convalescent plasma to placebo or standard care alone, and two RCTs reporting on 1597 participants with mild disease, comparing convalescent plasma to standard plasma. Convalescent plasma versus placebo or standard care alone We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (odds ratio (OR) 0.36, 95% CI 0.09 to 1.46; 8 per 1000; 2 RCTs, 536 participants; very low-certainty evidence). It may have little to no effect on admission to hospital or death within 28 days (RR 1.05, 95% CI 0.60 to 1.84; 117 per 1000; 1 RCT, 376 participants; low-certainty evidence), on time to COVID-19 symptom resolution (hazard ratio (HR) 1.05, 95% CI 0.85 to 1.30; 483 per 1000; 1 RCT, 376 participants; low-certainty evidence), on the risk of grades 3 and 4 adverse events (RR 1.29, 95% CI 0.75 to 2.19; 144 per 1000; 1 RCT, 376 participants; low-certainty evidence) and the risk of serious adverse events (RR 1.14, 95% CI 0.66 to 1.94; 133 per 1000; 1 RCT, 376 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (OR 0.30, 95% CI 0.05 to 1.75; 2 per 1000; 2 RCTs, 1597 participants; very low-certainty evidence). It probably reduces admission to hospital or death within 28 days (RR 0.49, 95% CI 0.31 to 0.75; 36 per 1000; 2 RCTs, 1595 participants; moderate-certainty evidence). Convalescent plasma may have little to no effect on initial symptom resolution at up to day 28 (RR 1.12, 95% CI 0.98 to 1.27; 1 RCT, 416 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. This is a living systematic review. We search monthly for new evidence and update the review when we identify relevant new evidence. AUTHORS' CONCLUSIONS: For the comparison of convalescent plasma versus placebo or standard care alone, our certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. It probably has little to no effect on SAEs. For individuals with mild disease, we have very-low to low certainty evidence for most primary outcomes and moderate certainty for hospital admission or death. There are 49 ongoing studies, and 33 studies reported as complete in a trials registry. Publication of ongoing studies might resolve some of the uncertainties around convalescent plasma therapy for people with asymptomatic or mild disease.

Hyperimmune immunoglobulin for people with COVID-19.

BACKGROUND: Hyperimmune immunoglobulin (hIVIG) contains polyclonal antibodies, which can be prepared from large amounts of pooled convalescent plasma or prepared from animal sources through immunisation. They are being investigated as a potential therapy for coronavirus disease 2019 (COVID-19). This review was previously part of a parent review addressing convalescent plasma and hIVIG for people with COVID-19 and was split to address hIVIG and convalescent plasma separately. OBJECTIVES: To assess the benefits and harms of hIVIG therapy for the treatment of people with COVID-19, and to maintain the currency of the evidence using a living systematic review approach. SEARCH METHODS: To identify completed and ongoing studies, we searched the World Health Organization (WHO) COVID-19 Research Database, the Cochrane COVID-19 Study Register, the Epistemonikos COVID-19 L*OVE Platform and Medline and Embase from 1 January 2019 onwards. We carried out searches on 31 March 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that evaluated hIVIG for COVID-19, irrespective of disease severity, age, gender or ethnicity. We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)), as well as studies that evaluated standard immunoglobulin. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methodology. To assess bias in included studies, we used RoB 2. We rated the certainty of evidence, using the GRADE approach, for the following outcomes: all-cause mortality, improvement and worsening of clinical status (for individuals with moderate to severe disease), quality of life, adverse events, and serious adverse events. MAIN RESULTS: We included five RCTs with 947 participants, of whom 688 received hIVIG prepared from humans, 18 received heterologous swine glyco-humanised polyclonal antibody, and 241 received equine-derived processed and purified F(ab')2 fragments. All participants were hospitalised with moderate-to-severe disease, most participants were not vaccinated (only 12 participants were vaccinated). The studies were conducted before or during the emergence of several SARS-CoV-2 variants of concern. There are no data for people with COVID-19 with no symptoms (asymptomatic) or people with mild COVID-19. We identified a further 10 ongoing studies evaluating hIVIG. Benefits of hIVIG prepared from humans We included data on one RCT (579 participants) that assessed the benefits and harms of hIVIG 0.4 g/kg compared to saline placebo. hIVIG may have little to no impact on all-cause mortality at 28 days (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.43 to 1.44; absolute effect 77 per 1000 with placebo versus 61 per 1000 (33 to 111) with hIVIG; low-certainty evidence). The evidence is very uncertain about the effect on worsening of clinical status at day 7 (RR 0.85, 95% CI 0.58 to 1.23; very low-certainty evidence). It probably has little to no impact on improvement of clinical status on day 28 (RR 1.02, 95% CI 0.97 to 1.08; moderate-certainty evidence). We did not identify any studies that reported quality-of-life outcomes, so we do not know if hIVIG has any impact on quality of life. Harms of hIVIG prepared from humans hIVIG may have little to no impact on adverse events at any grade on day 1 (RR 0.98, 95% CI 0.81 to 1.18; 431 per 1000; 1 study 579 participants; low-certainty evidence). Patients receiving hIVIG probably experience more adverse events at grade 3-4 severity than patients who receive placebo (RR 4.09, 95% CI 1.39 to 12.01; moderate-certainty evidence). hIVIG may have little to no impact on the composite outcome of serious adverse events or death up to day 28 (RR 0.72, 95% CI 0.45 to 1.14; moderate-certainty evidence). We also identified additional results on the benefits and harms of other dose ranges of hIVIG, not included in the summary of findings table, but summarised in additional tables. Benefits of animal-derived polyclonal antibodies We included data on one RCT (241 participants) to assess the benefits and harms of receptor-binding domain-specific polyclonal F(ab´)2 fragments of equine antibodies (EpAbs) compared to saline placebo. EpAbs may reduce all-cause mortality at 28 days (RR 0.60, 95% CI 0.26 to 1.37; absolute effect 114 per 1000 with placebo versus 68 per 1000 (30 to 156) ; low-certainty evidence). EpAbs may reduce worsening of clinical status up to day 28 (RR 0.67, 95% CI 0.38 to 1.18; absolute effect 203 per 1000 with placebo versus 136 per 1000 (77 to 240); low-certainty evidence). It may have some effect on improvement of clinical status on day 28 (RR 1.06, 95% CI 0.96 to 1.17; low-certainty evidence). We did not identify any studies that reported quality-of-life outcomes, so we do not know if EpAbs have any impact on quality of life. Harms of animal-derived polyclonal antibodies EpAbs may have little to no impact on the number of adverse events at any grade up to 28 days (RR 0.99, 95% CI 0.74 to 1.31; low-certainty evidence). Adverse events at grade 3-4 severity were not reported. Individuals receiving EpAbs may experience fewer serious adverse events than patients receiving placebo (RR 0.67, 95% CI 0.38 to 1.19; low-certainty evidence). We also identified additional results on the benefits and harms of other animal-derived polyclonal antibody doses, not included in the summary of findings table, but summarised in additional tables. AUTHORS' CONCLUSIONS: We included data from five RCTs that evaluated hIVIG compared to standard therapy, with participants with moderate-to-severe disease. As the studies evaluated different preparations (from humans or from various animals) and doses, we could not pool them. hIVIG prepared from humans may have little to no impact on mortality, and clinical improvement and worsening. hIVIG may increase grade 3-4 adverse events. Studies did not evaluate quality of life. RBD-specific polyclonal F(ab´)2 fragments of equine antibodies may reduce mortality and serious adverse events, and may reduce clinical worsening. However, the studies were conducted before or during the emergence of several SARS-CoV-2 variants of concern and prior to widespread vaccine rollout. As no studies evaluated hIVIG for participants with asymptomatic infection or mild disease, benefits for these individuals remains uncertain. This is a living systematic review. We search monthly for new evidence and update the review when we identify relevant new evidence.

Convalescent plasma for people with COVID-19: a living systematic review.

BACKGROUND: Convalescent plasma may reduce mortality in patients with viral respiratory diseases, and is being investigated as a potential therapy for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of this intervention is required. OBJECTIVES: To assess the effectiveness and safety of convalescent plasma transfusion in the treatment of people with COVID-19; and to maintain the currency of the evidence using a living systematic review approach. SEARCH METHODS: To identify completed and ongoing studies, we searched the World Health Organization (WHO) COVID-19 Global literature on coronavirus disease Research Database, MEDLINE, Embase, Cochrane COVID-19 Study Register, and the Epistemonikos COVID-19 L*OVE Platform. We searched monthly until 03 March 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) evaluating convalescent plasma for COVID-19, irrespective of disease severity, age, gender or ethnicity. We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)), as well as studies evaluating standard immunoglobulin. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methodology. To assess bias in included studies we used RoB 2. We used the GRADE approach to rate the certainty of evidence for the following outcomes: all-cause mortality at up to day 28, worsening and improvement of clinical status (for individuals with moderate to severe disease), hospital admission or death, COVID-19 symptoms resolution (for individuals with mild disease), quality of life, grade 3 or 4 adverse events, and serious adverse events. MAIN RESULTS: In this fourth review update version, we included 33 RCTs with 24,861 participants, of whom 11,432 received convalescent plasma. Of these, nine studies are single-centre studies and 24 are multi-centre studies. Fourteen studies took place in America, eight in Europe, three in South-East Asia, two in Africa, two in western Pacific and three in eastern Mediterranean regions and one in multiple regions. We identified a further 49 ongoing studies evaluating convalescent plasma, and 33 studies reporting as being completed. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease 29 RCTs investigated the use of convalescent plasma for 22,728 participants with moderate to severe disease. 23 RCTs with 22,020 participants compared convalescent plasma to placebo or standard care alone, five compared to standard plasma and one compared to human immunoglobulin. We evaluate subgroups on detection of antibodies detection, symptom onset, country income groups and several co-morbidities in the full text. Convalescent plasma versus placebo or standard care alone Convalescent plasma does not reduce all-cause mortality at up to day 28 (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.92 to 1.03; 220 per 1000; 21 RCTs, 19,021 participants; high-certainty evidence). It has little to no impact on need for invasive mechanical ventilation, or death (RR 1.03, 95% CI 0.97 to 1.11; 296 per 1000; 6 RCTs, 14,477 participants; high-certainty evidence) and has no impact on whether participants are discharged from hospital (RR 1.00, 95% CI 0.97 to 1.02; 665 per 1000; 6 RCTs, 12,721 participants; high-certainty evidence). Convalescent plasma may have little to no impact on quality of life (MD 1.00, 95% CI -2.14 to 4.14; 1 RCT, 483 participants; low-certainty evidence). Convalescent plasma may have little to no impact on the risk of grades 3 and 4 adverse events (RR 1.17, 95% CI 0.96 to 1.42; 212 per 1000; 6 RCTs, 2392 participants; low-certainty evidence). It has probably little to no effect on the risk of serious adverse events (RR 1.14, 95% CI 0.91 to 1.44; 135 per 1000; 6 RCTs, 3901 participants; moderate-certainty evidence). Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces or increases all-cause mortality at up to day 28 (RR 0.73, 95% CI 0.45 to 1.19; 129 per 1000; 4 RCTs, 484 participants; very low-certainty evidence). We are uncertain whether convalescent plasma reduces or increases the need for invasive mechanical ventilation, or death (RR 5.59, 95% CI 0.29 to 108.38; 311 per 1000; 1 study, 34 participants; very low-certainty evidence) and whether it reduces or increases the risk of serious adverse events (RR 0.80, 95% CI 0.55 to 1.15; 236 per 1000; 3 RCTs, 327 participants; very low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus human immunoglobulin Convalescent plasma may have little to no effect on all-cause mortality at up to day 28 (RR 1.07, 95% CI 0.76 to 1.50; 464 per 1000; 1 study, 190 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and mild disease We identified two RCTs reporting on 536 participants, comparing convalescent plasma to placebo or standard care alone, and two RCTs reporting on 1597 participants with mild disease, comparing convalescent plasma to standard plasma. Convalescent plasma versus placebo or standard care alone We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (odds ratio (OR) 0.36, 95% CI 0.09 to 1.46; 8 per 1000; 2 RCTs, 536 participants; very low-certainty evidence). It may have little to no effect on admission to hospital or death within 28 days (RR 1.05, 95% CI 0.60 to 1.84; 117 per 1000; 1 RCT, 376 participants; low-certainty evidence), on time to COVID-19 symptom resolution (hazard ratio (HR) 1.05, 95% CI 0.85 to 1.30; 483 per 1000; 1 RCT, 376 participants; low-certainty evidence), on the risk of grades 3 and 4 adverse events (RR 1.29, 95% CI 0.75 to 2.19; 144 per 1000; 1 RCT, 376 participants; low-certainty evidence) and the risk of serious adverse events (RR 1.14, 95% CI 0.66 to 1.94; 133 per 1000; 1 RCT, 376 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. Convalescent plasma versus standard plasma We are uncertain whether convalescent plasma reduces all-cause mortality at up to day 28 (OR 0.30, 95% CI 0.05 to 1.75; 2 per 1000; 2 RCTs, 1597 participants; very low-certainty evidence). It probably reduces admission to hospital or death within 28 days (RR 0.49, 95% CI 0.31 to 0.75; 36 per 1000; 2 RCTs, 1595 participants; moderate-certainty evidence). Convalescent plasma may have little to no effect on initial symptom resolution at up to day 28 (RR 1.12, 95% CI 0.98 to 1.27; 1 RCT, 416 participants; low-certainty evidence). We did not identify any study reporting other key outcomes. This is a living systematic review. We search monthly for new evidence and update the review when we identify relevant new evidence. AUTHORS' CONCLUSIONS: For the comparison of convalescent plasma versus placebo or standard care alone, our certainty in the evidence that convalescent plasma for individuals with moderate to severe disease does not reduce mortality and has little to no impact on clinical improvement or worsening is high. It probably has little to no effect on SAEs. For individuals with mild disease, we have low certainty evidence for our primary outcomes. There are 49 ongoing studies, and 33 studies reported as complete in a trials registry. Publication of ongoing studies might resolve some of the uncertainties around convalescent plasma therapy for people with asymptomatic or mild disease.

ANTECEDENTES: El plasma de convaleciente podría reducir la mortalidad en pacientes con enfermedades respiratorias víricas, y se está investigando como posible tratamiento para la enfermedad por coronavirus 2019 (covid­19). Se requiere un profundo conocimiento del conjunto de evidencia actual sobre los beneficios y riesgos de esta intervención. OBJETIVOS: Evaluar la efectividad y seguridad de la transfusión de plasma de convaleciente en el tratamiento de las personas con covid­19; y mantener la vigencia de la evidencia con un enfoque de revisión sistemática continua. MÉTODOS DE BÚSQUEDA: Para identificar estudios en curso y completados, se realizaron búsquedas en la base de datos COVID­19 de la OMS: literatura global sobre la enfermedad por coronavirus, MEDLINE, Embase, el Registro Cochrane de Estudios de covid­19 y la Plataforma COVID­19 L*OVE de Epistemonikos. Se realizaron búsquedas mensuales hasta el 3 de marzo de 2022. CRITERIOS DE SELECCIÓN: Se incluyeron ensayos controlados aleatorizados (ECA) que evaluaron el plasma de convaleciente para la covid­19, independientemente de la gravedad de la enfermedad, la edad, el sexo o el origen étnico. Se excluyeron los estudios que incluyeron poblaciones con otras enfermedades por coronavirus, como el síndrome respiratorio agudo grave (SARS) o el síndrome respiratorio de Oriente Medio (MERS), así como los estudios que evaluaron la inmunoglobulina estándar. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Se siguió la metodología estándar de Cochrane. Para evaluar el sesgo en los estudios incluidos se utilizó la herramienta RoB 2. Se utilizó el método GRADE para evaluar la certeza de la evidencia para los siguientes desenlaces: mortalidad por todas las causas hasta el día 28, empeoramiento y mejoría del estado clínico (para personas con enfermedad moderada a grave), ingreso hospitalario o muerte, resolución de los síntomas de covid­19 (para personas con enfermedad leve), calidad de vida, eventos adversos de grado 3 o 4 y eventos adversos graves. RESULTADOS PRINCIPALES: En esta cuarta versión actualizada de la revisión se incluyeron 33 ECA con 24 861 participantes, de los cuales 11 432 recibieron plasma de convaleciente. De ellos, 9 estudios son unicéntricos y 24 multicéntricos. Se realizaron 14 estudios en América, 8 en Europa, 3 en el Sudeste Asiático, 2 en África, 2 en el Pacífico occidental, 3 en el Mediterráneo oriental y 1 en varias regiones. Se identificaron otros 49 estudios en curso que evaluaron el plasma de convaleciente, y 33 estudios que informaban de que se habían completado. Personas con un diagnóstico confirmado de covid­19 y enfermedad de moderada a grave El uso de plasma de convaleciente se investigó en 29 ECA con 22 728 participantes con enfermedad moderada a grave. En 23 ECA con 22 020 participantes se comparó el plasma de convaleciente con el placebo o la atención habitual sola, en 5 se comparó con plasma estándar y en 1, con inmunoglobulina humana. Se evalúan subgrupos sobre detección de anticuerpos, aparición de síntomas, grupos de ingresos de países y varias comorbilidades en el texto completo. Plasma de convaleciente versus placebo o atención habitual sola El plasma de convaleciente no reduce la mortalidad por todas las causas hasta el día 28 (razón de riesgos [RR] 0,98; intervalo de confianza [IC] del 95%: 0,92 a 1,03; 220 por cada 1000; 21 ECA, 19 021 participantes; evidencia de certeza alta). Tiene poca o ninguna repercusión en la necesidad de ventilación mecánica invasiva o la muerte (RR 1,03; IC del 95%: 0,97 a 1,11; 296 por cada 1000; seis ECA, 14 477 participantes; evidencia de certeza alta) y no tiene ningún efecto en si los participantes reciben el alta hospitalaria (RR 1,00; IC de 95%: 0,97 a 1,02; 665 por cada 1000; seis ECA, 12 721 participantes; evidencia de certeza alta). El plasma de convaleciente podría tener poca o ninguna repercusión en la calidad de vida (DM 1,00; IC del 95%: ­2,14 a 4,14; un ECA, 483 participantes; evidencia de certeza baja). El plasma de convaleciente podría tener poco o ningún efecto en el riesgo de eventos adversos de grado 3 y 4 (RR 1,17; IC del 95%: 0,96 a 1,42; 212 por cada 1000; seis ECA, 2392 participantes; evidencia de certeza baja). Es probable que tenga poco o ningún efecto sobre el riesgo de eventos adversos graves (RR 1,14; IC del 95%: 0,91 a 1,44; 135 por cada 1000; seis ECA, 3901 participantes; evidencia de certeza moderada). Plasma de convaleciente versus plasma estándar No se sabe si el plasma de convaleciente reduce o aumenta la mortalidad por cualquier causa hasta el día 28 (RR 0,73; IC del 95%: 0,45 a 1,19; 129 por cada 1000; cuatro ECA, 484 participantes; evidencia de certeza muy baja). No se sabe si el plasma de convaleciente reduce o aumenta la necesidad de ventilación mecánica invasiva o la muerte (RR 5,59; IC del 95%: 0,29 a 108,38; 311 por cada 1000; un estudio, 34 participantes; evidencia de certeza muy baja) ni si reduce o aumenta el riesgo de eventos adversos graves (RR 0,80; IC 95%: 0,55 a 1,15; 236 por cada 1000; tres ECA, 327 participantes; evidencia de certeza muy baja). No se identificó ningún estudio que informara sobre otros desenlaces clave. Plasma de convaleciente versus inmunoglobulina humana El plasma de convaleciente podría tener poco o ningún efecto sobre la mortalidad por cualquier causa hasta el día 28 (RR 1,07; IC del 95%: 0,76 a 1,50; 464 por cada 1000; un estudio, 190 participantes; evidencia de certeza baja). No se identificó ningún estudio que informara sobre otros desenlaces clave. Personas con un diagnóstico confirmado de infección por SARS­CoV­2 y enfermedad leve Se identificaron dos ECA, con 536 participantes, que compararon el plasma de convaleciente con placebo o atención habitual sola y dos ECA, con 1597 participantes con enfermedad leve, que compararon el plasma de convaleciente con plasma estándar. Plasma de convaleciente versus placebo o atención habitual sola No se sabe si el plasma de convaleciente reduce la mortalidad por cualquier causa hasta el día 28 (odds ratio [OR] 0,36; IC del 95%: 0,09 a 1,46; 8 por cada 1000; dos ECA, 536 participantes; evidencia de certeza muy baja). Podría tener poco o ningún efecto en el ingreso hospitalario o la muerte a los 28 días (RR 1,05; IC del 95%: 0,60 a 1,84; 117 por cada 1000; un ECA, 376 participantes; evidencia de certeza baja), en el tiempo hasta la resolución de los síntomas de covid­19 (cociente de riesgos instantáneos [CRI] 1,05; IC del 95%: 0,85 a 1,30; 483 por cada 1000; un ECA, 376 participantes; evidencia de certeza baja), en el riesgo de eventos adversos de grados 3 y 4 (RR 1,29; IC del 95%: 0,75 a 2,19; 144 por cada 1000; un ECA, 376 participantes; evidencia de certeza baja) y en el riesgo de eventos adversos graves (RR 1,14; IC del 95%: 0,66 a 1,94; 133 por cada 1000; un ECA, 376 participantes; evidencia de certeza baja). No se identificó ningún estudio que informara sobre otros desenlaces clave. Plasma de convaleciente versus plasma estándar No se sabe si el plasma de convaleciente reduce la mortalidad por cualquier causa hasta el día 28 (OR 0,30; IC del 95%: 0,05 a 1,75; 2 por cada 1000; dos ECA, 1597 participantes; evidencia de certeza muy baja). Es probable que reduzca el ingreso hospitalario o la muerte a los 28 días (RR 0,49; IC del 95%: 0,31 a 0,75; 36 por cada 1000; dos ECA, 1595 participantes; evidencia de certeza moderada). El plasma de convaleciente podría tener poco o ningún efecto sobre la resolución inicial de los síntomas hasta el día 28 (RR 1,12; IC del 95%: 0,98 a 1,27; un ECA, 416 participantes; evidencia de certeza baja). No se identificó ningún estudio que informara sobre otros desenlaces clave. Esta es una revisión sistemática continua. Cada mes se busca nueva evidencia y se actualiza la revisión cuando se identifica evidencia nueva relevante. CONCLUSIONES DE LOS AUTORES: Para la comparación del plasma de convaleciente versus placebo o la atención habitual sola, existe evidencia de certeza alta de que el plasma de convaleciente para personas con enfermedad moderada a grave no reduce la mortalidad y tiene poco o ningún efecto en la mejoría o el empeoramiento clínico. Es probable que tenga poco o ningún efecto en los eventos adversos graves. Para las personas con enfermedad leve, existe evidencia de certeza baja para los desenlaces principales. Hay 49 estudios en curso y 33 estudios que declaran estar completados en un registro de ensayos. La publicación de los estudios en curso podría resolver algunas de las incertidumbres en torno al tratamiento con plasma de convaleciente para personas con enfermedad asintomática o leve.

Clinical Practice Guidelines From the Association for the Advancement of Blood and Biotherapies (AABB): COVID-19 Convalescent Plasma.

DESCRIPTION: Coronavirus disease 2019 convalescent plasma (CCP) has emerged as a potential treatment of COVID-19. However, meta-analysis data and recommendations are limited. The Association for the Advancement of Blood and Biotherapies (AABB) developed clinical practice guidelines for the appropriate use of CCP. METHODS: These guidelines are based on 2 living systematic reviews of randomized controlled trials (RCTs) evaluating CCP from 1 January 2019 to 26 January 2022. There were 33 RCTs assessing 21 916 participants. The results were summarized using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method. An expert panel reviewed the data using the GRADE framework to formulate recommendations. RECOMMENDATION 1 (OUTPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for outpatients with COVID-19 who are at high risk for disease progression (weak recommendation, moderate-certainty evidence). RECOMMENDATION 2 (INPATIENT): The AABB recommends against CCP transfusion for unselected hospitalized persons with moderate or severe disease (strong recommendation, high-certainty evidence). This recommendation does not apply to immunosuppressed patients or those who lack antibodies against SARS-CoV-2. RECOMMENDATION 3 (INPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for hospitalized patients with COVID-19 who do not have SARS-CoV-2 antibodies detected at admission (weak recommendation, low-certainty evidence). RECOMMENDATION 4 (INPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for hospitalized patients with COVID-19 and preexisting immunosuppression (weak recommendation, low-certainty evidence). RECOMMENDATION 5 (PROPHYLAXIS): The AABB suggests against prophylactic CCP transfusion for uninfected persons with close contact exposure to a person with COVID-19 (weak recommendation, low-certainty evidence). GOOD CLINICAL PRACTICE STATEMENT: CCP is most effective when transfused with high neutralizing titers to infected patients early after symptom onset.

Interventions to increase COVID-19 vaccine uptake: a scoping review.

BACKGROUND: Vaccines are effective in preventing severe COVID-19, a disease for which few treatments are available and which can lead to disability or death. Widespread vaccination against COVID-19 may help protect those not yet able to get vaccinated. In addition, new and vaccine-resistant mutations of SARS-CoV-2 may be less likely to develop if the spread of COVID-19 is limited. Different vaccines are now widely available in many settings. However, vaccine hesitancy is a serious threat to the goal of nationwide vaccination in many countries and poses a substantial threat to population health. This scoping review maps interventions aimed at increasing COVID-19 vaccine uptake and decreasing COVID-19 vaccine hesitancy. OBJECTIVES: To scope the existing research landscape on interventions to enhance the willingness of different populations to be vaccinated against COVID-19, increase COVID-19 vaccine uptake, or decrease COVID-19 vaccine hesitancy, and to map the evidence according to addressed populations and intervention categories. SEARCH METHODS: We searched Cochrane COVID-19 Study Register, Web of Science (Science Citation Index Expanded and Emerging Sources Citation Index), WHO COVID-19 Global literature on coronavirus disease, PsycINFO, and CINAHL to 11 October 2021. SELECTION CRITERIA: We included studies that assess the impact of interventions implemented to enhance the willingness of different populations to be vaccinated against COVID-19, increase vaccine uptake, or decrease COVID-19 vaccine hesitancy. We included randomised controlled trials (RCTs), non-randomised studies of intervention (NRSIs), observational studies and case studies with more than 100 participants. Furthermore, we included systematic reviews and meta-analyses. We did not limit the scope of the review to a specific population or to specific outcomes assessed. We excluded interventions addressing hesitancy towards vaccines for diseases other than COVID-19. DATA COLLECTION AND ANALYSIS: Data were analysed according to a protocol uploaded to the Open Science Framework. We used an interactive scoping map to visualise the results of our scoping review. We mapped the identified interventions according to pre-specified intervention categories, that were adapted to better fit the evidence. The intervention categories were: communication interventions, policy interventions, educational interventions, incentives (both financial and non-financial), interventions to improve access, and multidimensional interventions. The study outcomes were also included in the mapping. Furthermore, we mapped the country in which the study was conducted, the addressed population, and whether the design was randomised-controlled or not. MAIN RESULTS: We included 96 studies in the scoping review, 35 of which are ongoing and 61 studies with published results. We did not identify any relevant systematic reviews. For an overview, please see the interactive scoping map (https://tinyurl.com/2p9jmx24) STUDIES WITH PUBLISHED RESULTS Of the 61 studies with published results, 46 studies were RCTs and 15 NRSIs. The interventions investigated in the studies were heterogeneous with most studies testing communication strategies to enhance COVID-19 vaccine uptake. Most studies assessed the willingness to get vaccinated as an outcome. The majority of studies were conducted in English-speaking high-income countries. Moreover, most studies investigated digital interventions in an online setting. Populations that were addressed were diverse. For example, studies targeted healthcare workers, ethnic minorities in the USA, students, soldiers, at-risk patients, or the general population.  ONGOING STUDIES Of the 35 ongoing studies, 29 studies are RCTs and six NRSIs. Educational and communication interventions were the most used types of interventions. The majority of ongoing studies plan to assess vaccine uptake as an outcome. Again, the majority of studies are being conducted in English-speaking high-income countries. In contrast to the studies with published results, most ongoing studies will not be conducted online. Addressed populations range from minority populations in the USA to healthcare workers or students. Eleven ongoing studies have estimated completion dates in 2022.   AUTHORS' CONCLUSIONS: We were able to identify and map a variety of heterogeneous interventions for increasing COVID-19 vaccine uptake or decreasing vaccine hesitancy. Our results demonstrate that this is an active field of research with 61 published studies and 35 studies still ongoing. This review gives a comprehensive overview of interventions to increase COVID-19 vaccine uptake and can be the foundation for subsequent systematic reviews on the effectiveness of interventions to increase COVID-19 vaccine uptake.  A research gap was shown for studies conducted in low and middle-income countries and studies investigating policy interventions and improved access, as well as for interventions addressing children and adolescents. As COVID-19 vaccines become more widely available, these populations and interventions should not be neglected in research. AUTHORS CONCLUSIONS: We were able to identify and map a variety of heterogeneous interventions for increasing COVID-19 vaccine uptake or decreasing vaccine hesitancy. Our results demonstrate that this is an active field of research with 61 published studies and 35 studies still ongoing. This review gives a comprehensive overview of interventions to increase COVID-19 vaccine uptake and can be the foundation for subsequent systematic reviews on the effectiveness of interventions to increase COVID-19 vaccine uptake.  A research gap was shown for studies conducted in low and middle-income countries and studies investigating policy interventions and improved access, as well as for interventions addressing children and adolescents. As COVID-19 vaccines become more widely available, these populations and interventions should not be neglected in research.

Effectiveness, immunogenicity, and safety of COVID-19 vaccines for individuals with hematological malignancies: a systematic review.

The efficacy of SARS-CoV-2 vaccination in patients with hematological malignancies (HM) appears limited due to disease and treatment-associated immune impairment. We conducted a systematic review of prospective studies published from 10/12/2021 onwards in medical databases to assess clinical efficacy parameters, humoral and cellular immunogenicity and adverse events (AE) following two doses of COVID-19 approved vaccines. In 57 eligible studies reporting 7393 patients, clinical outcomes were rarely reported and rates of SARS-CoV-2 infection (range 0-11.9%), symptomatic disease (0-2.7%), hospital admission (0-2.8%), or death (0-0.5%) were low. Seroconversion rates ranged from 38.1-99.1% across studies with the highest response rate in myeloproliferative diseases and the lowest in patients with chronic lymphocytic leukemia. Patients with B-cell depleting treatment had lower seroconversion rates as compared to other targeted treatments or chemotherapy. The vaccine-induced T-cell response was rarely and heterogeneously reported (26.5-85.9%). Similarly, AEs were rarely reported (0-50.9% ≥1 AE, 0-7.5% ≥1 serious AE). In conclusion, HM patients present impaired humoral and cellular immune response to COVID-19 vaccination with disease and treatment specific response patterns. In light of the ongoing pandemic with the easing of mitigation strategies, new approaches to avert severe infection are urgently needed for this vulnerable patient population that responds poorly to current COVID-19 vaccine regimens.

Methodological challenges for living systematic reviews conducted during the COVID-19 pandemic: A concept paper.

BACKGROUND: A living systematic review (LSR) is an emerging review type that makes use of continual updating. In the COVID-19 pandemic, we were confronted with a shifting epidemiological landscape, clinical uncertainties and evolving evidence. These unexpected challenges compelled us to amend standard LSR methodology. OBJECTIVE AND OUTLINE: Our primary objective is to discuss some challenges faced when conducting LSRs in the context of the COVID-19 pandemic, and to provide methodological guidance for others doing similar work. Based on our experience and lessons learned from two Cochrane LSRs and challenges identified in several non-Cochrane LSRs, we highlight methodological considerations, particularly with regards to the study design, interventions and comparators, changes in outcome measure, and the search strategy. We discuss when to update, or rather when not to update the review, and the importance of transparency when reporting changes. LESSONS LEARNED AND CONCLUSION: We learned that a LSR is a very suitable review type for the pandemic context, even in the face of new methodological and clinical challenges. Our experience showed that the decision for updating a LSR depends not only on the evolving disease or emerging evidence, but also on the individual review question and the review teams' resources.

Vitamin D supplementation for the treatment of COVID-19: a living systematic review.

BACKGROUND: The role of vitamin D supplementation as a treatment for COVID-19 has been a subject of considerable discussion. A thorough understanding of the current evidence regarding the effectiveness and safety of vitamin D supplementation for COVID-19 based on randomised controlled trials is required. OBJECTIVES: To assess whether vitamin D supplementation is effective and safe for the treatment of COVID-19 in comparison to an active comparator, placebo, or standard of care alone, and to maintain the currency of the evidence, using a living systematic review approach. SEARCH METHODS: We searched the Cochrane COVID-19 Study Register, Web of Science and the WHO COVID-19 Global literature on coronavirus disease to identify completed and ongoing studies without language restrictions to 11 March 2021. SELECTION CRITERIA: We followed standard Cochrane methodology. We included randomised controlled trials (RCTs) evaluating vitamin D supplementation for people with COVID-19, irrespective of disease severity, age, gender or ethnicity. We excluded studies investigating preventive effects, or studies including populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)). DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane risk of bias tool (ROB 2) for RCTs. We rated the certainty of evidence using the GRADE approach for the following prioritised outcome categories: individuals with moderate or severe COVID-19: all-cause mortality, clinical status, quality of life, adverse events, serious adverse events, and for individuals with asymptomatic or mild disease: all-cause mortality, development of severe clinical COVID-19 symptoms, quality of life, adverse events, serious adverse events. MAIN RESULTS: We identified three RCTs with 356 participants, of whom 183 received vitamin D. In accordance with the World Health Organization (WHO) clinical progression scale, two studies investigated participants with moderate or severe disease, and one study individuals with mild or asymptomatic disease. The control groups consisted of placebo treatment or standard of care alone. Effectiveness of vitamin D supplementation for people with COVID-19 and moderate to severe disease We included two studies with 313 participants. Due to substantial clinical and methodological diversity of both studies, we were not able to pool data. Vitamin D status was unknown in one study, whereas the other study reported data for vitamin D deficient participants. One study administered multiple doses of oral calcifediol at days 1, 3 and 7,  whereas the other study gave a single high dose of oral cholecalciferol at baseline. We assessed one study with low risk of bias for effectiveness outcomes, and the other with some concerns about randomisation and selective reporting. All-cause mortality at hospital discharge (313 participants) We found two studies reporting data for this outcome. One study reported no deaths when treated with vitamin D out of 50 participants, compared to two deaths out of 26 participants in the control group (Risk ratio (RR) 0.11, 95% confidence interval (CI) 0.01 to 2.13). The other study reported nine deaths out of 119 individuals in the vitamin D group, whereas six participants out of 118 died in the placebo group (RR 1.49, 95% CI 0.55 to 4.04]. We are very uncertain whether vitamin D has an effect on all-cause mortality at hospital discharge (very low-certainty evidence). Clinical status assessed by the need for invasive mechanical ventilation (237 participants) We found one study reporting data for this outcome. Nine out of 119 participants needed invasive mechanical ventilation when treated with vitamin D, compared to 17 out of 118 participants in the placebo group (RR 0.52, 95% CI 0.24 to 1.13). Vitamin D supplementation may decrease need for invasive mechanical ventilation, but the evidence is uncertain (low-certainty evidence). Quality of life We did not find data for quality of life. Safety of vitamin D supplementation for people with COVID-19 and moderate to severe disease We did not include data from one study, because assessment of serious adverse events was not described and we are concerned that data might have been inconsistently measured. This study reported vomiting in one out of 119 participants immediately after vitamin D intake (RR 2.98, 95% CI 0.12 to 72.30). We are very uncertain whether vitamin D supplementation is associated with higher risk for adverse events (very low-certainty). Effectiveness and safety of vitamin D supplementation for people with COVID-19 and asymptomatic or mild disease We found one study including 40 individuals, which did not report our prioritised outcomes, but instead data for viral clearance, inflammatory markers, and vitamin D serum levels. The authors reported no events of hypercalcaemia, but recording and assessment of further adverse events remains unclear. Authors administered oral cholecalciferol in daily doses for at least 14 days, and continued with weekly doses if vitamin D blood levels were > 50 ng/mL. AUTHORS' CONCLUSIONS: There is currently insufficient evidence to determine the benefits and harms of vitamin D supplementation as a treatment of COVID-19. The evidence for the effectiveness of vitamin D supplementation for the treatment of COVID-19 is very uncertain. Moreover, we found only limited safety information, and were concerned about consistency in measurement and recording of these outcomes. There was substantial clinical and methodological heterogeneity of included studies, mainly because of different supplementation strategies, formulations, vitamin D status of participants, and reported outcomes. There is an urgent need for well-designed and adequately powered randomised controlled trials (RCTs) with an appropriate randomisation procedure, comparability of study arms and preferably double-blinding. We identified 21 ongoing and three completed studies without published results, which indicates that these needs will be addressed and that our findings are subject to change in the future. Due to the living approach of this work, we will update the review periodically.

Convalescent plasma or hyperimmune immunoglobulin for people with COVID-19: a living systematic review.

BACKGROUND: Convalescent plasma and hyperimmune immunoglobulin may reduce mortality in patients with viral respiratory diseases, and are being investigated as potential therapies for coronavirus disease 2019 (COVID-19). A thorough understanding of the current body of evidence regarding benefits and risks of these interventions is required.  OBJECTIVES: Using a living systematic review approach, to assess whether convalescent plasma or hyperimmune immunoglobulin transfusion is effective and safe in the treatment of people with COVID-19; and to maintain the currency of the evidence. SEARCH METHODS: To identify completed and ongoing studies, we searched the World Health Organization (WHO) COVID-19 Global literature on coronavirus disease Research Database, MEDLINE, Embase, the Cochrane COVID-19 Study Register, the Epistemonikos COVID-19 L*OVE Platform, and trial registries. Searches were done on 17 March 2021. SELECTION CRITERIA: We included randomised controlled trials (RCTs) evaluating convalescent plasma or hyperimmune immunoglobulin for COVID-19, irrespective of disease severity, age, gender or ethnicity. For safety assessments, we also included non-controlled non-randomised studies of interventions (NRSIs) if 500 or more participants were included. We excluded studies that included populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)), as well as studies evaluating standard immunoglobulin. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane 'Risk of Bias 2' tool for RCTs, and for NRSIs, the assessment criteria for observational studies, provided by Cochrane Childhood Cancer. We rated the certainty of evidence, using the GRADE approach, for the following outcomes: all-cause mortality, improvement and worsening of clinical status (for individuals with moderate to severe disease), development of severe clinical COVID-19 symptoms (for individuals with asymptomatic or mild disease), quality of life (including fatigue and functional independence), grade 3 or 4 adverse events, and serious adverse events. MAIN RESULTS: We included 13 studies (12 RCTs, 1 NRSI) with 48,509 participants, of whom 41,880 received convalescent plasma. We did not identify any completed studies evaluating hyperimmune immunoglobulin. We identified a further 100 ongoing studies evaluating convalescent plasma or hyperimmune immunoglobulin, and 33 studies reporting as being completed or terminated. Individuals with a confirmed diagnosis of COVID-19 and moderate to severe disease Eleven RCTs and one NRSI investigated the use of convalescent plasma for 48,349 participants with moderate to severe disease. Nine RCTs compared convalescent plasma to placebo treatment or standard care alone, and two compared convalescent plasma to standard plasma (results not included in abstract). Effectiveness of convalescent plasma We included data on nine RCTs (12,875 participants) to assess the effectiveness of convalescent plasma compared to placebo or standard care alone.  Convalescent plasma does not reduce all-cause mortality at up to day 28 (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.92 to 1.05; 7 RCTs, 12,646 participants; high-certainty evidence). It has little to no impact on clinical improvement for all participants when assessed by liberation from respiratory support (RR not estimable; 8 RCTs, 12,682 participants; high-certainty evidence). It has little to no impact on the chance of being weaned or liberated from invasive mechanical ventilation for the subgroup of participants requiring invasive mechanical ventilation at baseline (RR 1.04, 95% CI 0.57 to 1.93; 2 RCTs, 630 participants; low-certainty evidence). It does not reduce the need for invasive mechanical ventilation (RR 0.98, 95% CI 0.89 to 1.08; 4 RCTs, 11,765 participants; high-certainty evidence). We did not identify any subgroup differences.  We did not identify any studies reporting quality of life, and therefore, do not know whether convalescent plasma has any impact on quality of life. One RCT assessed resolution of fatigue on day 7, but we are very uncertain about the effect (RR 1.21, 95% CI 1.02 to 1.42; 309 participants; very low-certainty evidence).  Safety of convalescent plasma We included results from eight RCTs, and one NRSI, to assess the safety of convalescent plasma. Some of the RCTs reported on safety data only for the convalescent plasma group.  We are uncertain whether convalescent plasma increases or reduces the risk of grade 3 and 4 adverse events (RR 0.90, 95% CI 0.58 to 1.41; 4 RCTs, 905 participants; low-certainty evidence), and serious adverse events (RR 1.24, 95% CI 0.81 to 1.90; 2 RCTs, 414 participants; low-certainty evidence).  A summary of reported events of the NRSI (reporting safety data for 20,000 of 35,322 transfused participants), and four RCTs reporting safety data only for transfused participants (6125 participants) are included in the full text. Individuals with a confirmed diagnosis of SARS-CoV-2 infection and asymptomatic or mild disease We identified one RCT reporting on 160 participants, comparing convalescent plasma to placebo treatment (saline).  Effectiveness of convalescent plasma We are very uncertain about the effect of convalescent plasma on all-cause mortality (RR 0.50, 95% CI 0.09 to 2.65; very low-certainty evidence). We are uncertain about the effect of convalescent plasma on developing severe clinical COVID-19 symptoms (RR not estimable; low-certainty evidence).  We identified no study reporting quality of life.  Safety of convalescent plasma We do not know whether convalescent plasma is associated with a higher risk of grade 3 or 4 adverse events (very low-certainty evidence), or serious adverse events (very low-certainty evidence). This is a living systematic review. We search weekly for new evidence and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review. AUTHORS' CONCLUSIONS: We have high certainty in the evidence that convalescent plasma for the treatment of individuals with moderate to severe disease does not reduce mortality and has little to no impact on measures of clinical improvement. We are uncertain about the adverse effects of convalescent plasma. While major efforts to conduct research on COVID-19 are being made, heterogeneous reporting of outcomes is still problematic. There are 100 ongoing studies and 33 studies reporting in a study registry as being completed or terminated. Publication of ongoing studies might resolve some of the uncertainties around hyperimmune immunoglobulin therapy for people with any disease severity, and convalescent plasma therapy for people with asymptomatic or mild disease.