Are convalescent plasma stocks collected during former COVID-19 waves still effective against current SARS-CoV-2 variants?

Fresh frozen plasma for neutralizing SARS-CoV-2: "An exploratory cross-sectional study and review of the state of the art"

Restitution of humoral immunodeficiency is essential to clear SARS-CoV-2. Intravenous unspecific immunoglobulins are expensive and restricted. So recently donated fresh frozen plasma (FFP) could be useful in this scenario but, are all units neutralizing against SARS-CoV-2? We explored this on 52 donations obtained from "Centro de Transfusión, Tejidos y Células de Málaga, Spain", from April to June 2022. Donors status about SARS-CoV-2 previous infection or vaccination was unknown. Neutralizing activity (at dilutions≥1/160) against real Delta (not circulating), BA.2 (dominant circulating variant), BA.5 (irrupting variant), and BQ.1.1 and XBB.1.5 (not circulating yet) was determined. Higher anti-Spike IgG antibodies cut-offs predicted efficacy of FFP. Different cut-offs have been reported in the literature, but all papers have in common that levels over the higher range of quantification can predict neutralizing activity of recently donated FFP against circulating variants of concern, if used early after donation, not requiring clinical data from donors.

Evaluation of Neutralizing Capacity of Tixagevimab plus Cilgavimab (AZD7442) against Different SARS-CoV-2 Variants: A Case Report Study with Comparison to a Vaccinated Population

AZD7442 (150 mg of tixagevimab plus 150 mg of cilgavimab) has been approved for the preexposure prophylaxis of COVID-19 and for the treatment of adults and adolescents with COVID-19 who do not require supplemental oxygen and who are at increased risk of severe COVID-19. Thus, the aim of the present study is to evaluate the neutralizing capacity of tixagevimab and cilgavimab across different SARS-CoV-2 variants in two patients who received AZD7442 for immunoprophylaxis. A cohort of subjects (n = 45) who had received the BNT162b2 mRNA COVID-19 vaccine has been included to compare these two preventive strategies. Neutralizing antibody (NAb) titers against several variants were assessed against the wild-type, alpha, beta, gamma, delta, omicron BA.5, and XBB.1.5 variants. Binding antibodies have also been measured. NAbs T 1/2 for AZD7442 was 8.1 days (95% CI: 5.1-19.5 days) and was 11.8 days (95% CI: 7.9-23.7 days) for the primo-vaccination cohort. The time to reach neutralization negativity was 108.3 days (95% CI: 66.9-130.7) for AZD7442 compared to 95.4 days (95% CI: 31.0-119.7 days) for the primo-vaccination cohort. The time to reach NAbs' negativity differs between variants with the maximum value obtained for alpha (i.e., 101.1 days (95% CI: 30.0-135.4 days)) and the minimum obtained for beta (i.e., 61.2 days (95% CI: 37.8-77.1 days)). Our results reinforce the need of reviewing the use of AZD7442 in relation to variants of concern and potentially adapting its administration schedule. AZD7442 could be indicated for short-term prophylaxis in frail patients who may be acutely exposed to SARS-CoV-2.

The Importance of Geographic Proximity of Convalescent Plasma Donors

Donor-recipient proximity emerged as an important factor influencing the efficacy of COVID-19 convalescent plasma (CCP) treatment during the early stages of the COVID-19 pandemic. This relationship was uncovered while analyzing data collected in the collaborative Expanded Access Program (EAP) for CCP at Mayo Clinic, a project aimed to establish protocols for CCP use amid the uncertainty of the novel disease. Analysis of data from nearly 28,000 patients revealed a significant reduction in risk of 30-day mortality for those receiving near-sourced plasma when compared to those receiving distantly sourced plasma [pooled relative risk, 0.73 (95% CI 0.67-0.80)], prompting adjustments in treatment protocols at selected institutions, and highlighting the importance of proximity in optimizing CCP outcomes. Despite its significance, subsequent studies of CCP effectiveness in COVID-19 have often overlooked donor-recipient proximity. Our findings emphasize the importance of donor-recipient proximity in CCP treatment in the current pandemic, and we discuss potential methods for improving CCP efficacy in future pandemics. Our recommendations include prioritizing virus genotyping for vulnerable patients, establishing a robust testing infrastructure, and collecting additional donor data to enhance plasma selection. This chapter underscores the importance of comprehensive data collection and sharing to navigate the evolving landscape of newly emerging infectious diseases.

Exercise and Experiments of Nature

In this article, we highlight the contributions of passive experiments that address important exercise-related questions in integrative physiology and medicine. Passive experiments differ from active experiments in that passive experiments involve limited or no active intervention to generate observations and test hypotheses. Experiments of nature and natural experiments are two types of passive experiments. Experiments of nature include research participants with rare genetic or acquired conditions that facilitate exploration of specific physiological mechanisms. In this way, experiments of nature are parallel to classical "knockout" animal models among human research participants. Natural experiments are gleaned from data sets that allow population-based questions to be addressed. An advantage of both types of passive experiments is that more extreme and/or prolonged exposures to physiological and behavioral stimuli are possible in humans. In this article, we discuss a number of key passive experiments that have generated foundational medical knowledge or mechanistic physiological insights related to exercise. Both natural experiments and experiments of nature will be essential to generate and test hypotheses about the limits of human adaptability to stressors like exercise. © 2023 American Physiological Society. Compr Physiol 13:4879-4907, 2023.

Intranasal administration of convalescent plasma protects against SARS-CoV-2 infection in hamsters

BACKGROUND

Convalescent plasma (CP) transfusion is an early option for treating infections with pandemic potential, often preceding vaccine or antiviral drug rollout. Heterogenous findings from randomized clinical trials on transfusion of COVID-19 CP (CCP) have been reported. However, meta-analysis suggests that transfusion of high titer CCP is associated with a mortality benefit for COVID-19 outpatients or inpatients treated within 5 days after symptom onset, indicating the importance of early administration.

METHODS

We tested if CCP is an effective prophylactic against SARS-CoV-2 infection by the intranasal administration of 25 μL CCP/nostril (i.e. 0.01-0.06 mg anti-RBD antibodies/kg) in hamsters exposed to infected littermates.

FINDINGS

In this model, 40% of CCP treated hamsters were fully protected and 40% had significantly reduced viral loads, the remaining 20% was not protected. The effect seems dose-dependent because high-titer CCP from a vaccinated donor was more effective than low-titer CCP from a donation prior to vaccine rollout. Intranasal administration of human CCP resulted in a reactive (immune) response in hamster lungs, however this was not observed upon administration of hamster CCP.

INTERPRETATION

We conclude that CCP is an effective prophylactic when used directly at the site of primary infection. This option should be considered in future prepandemic preparedness plans.

FUNDING

Flanders Innovation & Entrepreneurship (VLAIO) and the Foundation for Scientific Research of the Belgian Red Cross Flanders.

Multi-institutional experience with COVID-19 convalescent plasma in children

BACKGROUND AND OBJECTIVES

Convalescent COVID-19 plasma (CCP) was developed and used worldwide as a treatment option by supplying passive immunity. Adult studies suggest administering high-titer CCP early in the disease course of patients who are expected to be antibody-negative; however, pediatric experience is limited. We created a multi-institutional registry to characterize pediatric patients (<18 years) who received CCP and to assess the safety of this intervention.

METHODS

A REDCap survey was distributed. The registry collected de-identified data including demographic information (age, gender, and underlying conditions), COVID-19 disease features and concurrent treatments, CCP transfusion and safety events, and therapy response.

RESULTS

Ninety-five children received CCP: 90 inpatients and 5 outpatients, with a median age of 10.2 years (range 0-17.9). They were predominantly Latino/Hispanic and White. The most frequent underlying medical conditions were chronic respiratory disease, immunosuppression, obesity, and genetic syndromes. CCP was primarily given as a treatment (95%) rather than prophylaxis (5%). Median total plasma dose administered and transfusion rates were 5.0 ml/kg and 2.6 ml/kg/h, respectively. The transfusions were well-tolerated, with 3 in 115 transfusions reporting mild reactions. No serious adverse events were reported. Severity scores decreased significantly 7 days after CCP transfusion or at discharge. Eighty-five patients (94.4%) survived to hospital discharge. All five outpatients survived to 60 days.

CONCLUSIONS

CCP was found to be safe and well-tolerated in children. CCP was frequently given concurrently with other COVID-19-directed treatments with improvement in clinical severity scores ≥7 days after CCP, but efficacy could not be evaluated in this study.

Efficacy and Safety of COVID-19 Convalescent Plasma in Hospitalized Patients-An Open-Label Phase II Clinical Trial

Background: COVID-19 convalescent plasma (CCP) is an important antiviral option for selected patients with COVID-19. Materials and Methods: In this open-label, phase 2, clinical trial conducted from 30 April 2020 till 10 May 2021 in the Republic of North Macedonia, we evaluated the efficacy and safety of CCP in hospitalized patients. Treatment was with a single unit of CCP having an anti-RBD IgG concentration higher than 5 AU/mL. Results: There were 189 patients that completed the study, of which 65 (34.4%) had WHO 8-point clinical progression scale score of 3 (requiring hospital care but not oxygen support), 65 (34.4%) had a score of 4 (hospitalized and requiring supplemental oxygen by mask or nasal prongs), and 59 (31.2%) had a score of 5 (hospitalized and requiring supplemental oxygen by non-invasive ventilation or high-flow oxygen). Mean age was 57 years (range 22−94), 78.5% were males, 80.4% had elevated body mass index, and 70.9% had comorbidity. Following CCP transfusion, we observed clinical improvement with increase rates in oxygenation-free days of 32.3% and 58.5% at 24 h and seven days after CCP transfusion, a decline in WHO scores, and reduced progression to severe disease (only one patient was admitted to ICU after CCP transfusion). Mortality in the entire cohort was 11.6% (22/189). We recorded 0% mortality in WHO score 3 (0/65) and in patients that received CCP transfusion in the first seven days of disease, 4.6% mortality in WHO score 4 (3/65), and 30.5% mortality in WHO score 5 (18/59). Mortality correlated with WHO score (Chi-square 19.3, p < 0.001) and with stay in the ICU (Chi-square 55.526, p ≤ 0.001). No severe adverse events were reported. Conclusions: This study showed that early administration of CCP to patients with moderate disease was a safe and potentially effective treatment for hospitalized COVID-19 patients. The trial was registered at clinicaltrials.gov (NCT04397523).

How do I implement an outpatient program for the administration of convalescent plasma for COVID-19?

Convalescent plasma, collected from donors who have recovered from a pathogen of interest, has been used to treat infectious diseases, particularly in times of outbreak, when alternative therapies were unavailable. The COVID-19 pandemic revived interest in the use of convalescent plasma. Large observational studies and clinical trials that were executed during the pandemic provided insight into how to use convalescent plasma, whereby high levels of antibodies against the pathogen of interest and administration early within the time course of the disease are critical for optimal therapeutic effect. Several studies have shown outpatient administration of COVID-19 convalescent plasma (CCP) to be both safe and effective, preventing clinical progression in patients when administered within the first week of COVID-19. The United States Food and Drug Administration expanded its emergency use authorization (EUA) to allow for the administration of CCP in an outpatient setting in December 2021, at least for immunocompromised patients or those on immunosuppressive therapy. Outpatient transfusion of CCP and infusion of monoclonal antibody therapies for a highly transmissible infectious disease introduces nuanced challenges related to infection prevention. Drawing on our experiences with the clinical and research use of CCP, we describe the logistical considerations and workflow spanning procurement of qualified products, infrastructure, staffing, transfusion, and associated management of adverse events. The purpose of this description is to facilitate the efforts of others intent on establishing outpatient transfusion programs for CCP and other antibody-based therapies.