We investigated feasibility and accuracy of an interferon-gamma release assay (IGRA) for detection of T cell responses to SARS-CoV-2. Whole blood IGRA accurately distinguished between convalescents and uninfected healthy blood donors with a predominantly CD4+ T cell response. SARS-CoV-2 IGRA may serve as a useful diagnostic tool in managing the COVID-19 pandemic.
Background Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in blood, also known as RNAemia, has been reported, but its prognostic implications are poorly understood. This study aimed to determine the frequency of SARS-CoV-2 RNA in plasma and its association with coronavirus disease 2019 (COVID-19) clinical severity. Methods An analytical cross-sectional study was performed in a single-center tertiary care institution and included consecutive inpatients and outpatients with confirmed COVID-19. The prevalence of SARS CoV-2 RNAemia and the strength of its association with clinical severity variables were examined and included intensive care unit (ICU) admission, invasive mechanical ventilation, and 30-day all-cause mortality. Results Paired nasopharyngeal and plasma samples were included from 85 patients. The median age was 55 years, and individuals with RNAemia were older than those with undetectable SARS-CoV-2 RNA in plasma (63 vs 50 years; P = .04). Comorbidities were frequent including obesity (37.6%), hypertension (30.6%), and diabetes mellitus (22.4%). RNAemia was detected in 28/85 (32.9%) of patients, including 22/28 (78.6%) who required hospitalization. In models adjusted for age, RNAemia was detected more frequently in individuals who developed severe disease including ICU admission (32.1 vs 14.0%; P = .04) and invasive mechanical ventilation (21.4% vs 3.5%; P = .02). All 4 deaths occurred in individuals with detectable RNAemia. An additional 121 plasma samples from 28 individuals with RNAemia were assessed longitudinally, and RNA was detected for a maximum duration of 10 days. Conclusions This study demonstrated a high proportion of SARS-CoV-2 RNAemia, and an association between RNAemia and clinical severity suggesting the potential utility of plasma viral testing as a prognostic indicator for COVID-19.
Background Data on the safety and efficacy of COVID-19 vaccination in people with a range of primary immune deficiencies are lacking since these patients were excluded from COVID-19 vaccine trials . This information may help in clinical management of this vulnerable patient group. Objective To assess humoral and T-cell immune responses after two doses of SARS-CoV-2 mRNA vaccines in patients with PIDs and functional B-cell defects. Methods A double-center retrospective review of patients with PID who completed COVID-19 mRNA vaccination and who had humoral responses assessed through SARS-CoV-2 spike protein receptor binding domain (RBD) IgG antibody levels with reflex assessment of the antibody to block RBD binding to ACE2 (hereafter referred to as ACE2 receptor blocking activity, as a surrogate test for neutralization) and T-cell response evaluated by an interferon-gamma release assay (IGRA). Immunization reactogenicity was also reviewed. Results A total of 33 patients with humoral defect were evaluated. 69.6% received BNT162b2 vaccine (Pfizer-BioNTech) and 30.3% received mRNA-1273 (Moderna). The mRNA vaccines were generally well tolerated without severe reactions. The IGRA was positive in 77.4% of our patients (24 of 31). About half of our subjects (16 of 33) had detectable RBD-specific IgG responses but only two of these 16 subjects had an ACE2 receptor blocking activity level of > 50%. Conclusion Vaccination of this cohort of PID patients with COVID-19 mRNA vaccines was safe and cellular immunity was stimulated in a majority. However, antibody responses to the spike protein RBD were less consistent, and, when detected, was not effective at ACE2 blocking. Clinical Implication mRNA vaccination may be less effective at preventing acquisition of SARS-CoV-2 in our cohort of PID patients with functional B-cell defects. The Induction of SARS-CoV-2 spike protein-specific T-cell immunity by vaccination might help reduce the severity of disease in these patients.
24Background: Detection of SARS-CoV-2 RNA in the blood, also known as RNAemia, has been 25 reported, but its prognostic implications are not well understood. This study aimed to determine 26 the frequency of SARS-CoV-2 RNA in plasma and its association with the clinical severity of 27 Methods: An analytical cross-sectional study was performed in a single-center tertiary care 29 institution in northern California and included consecutive inpatients and outpatients with COVID-30 19 confirmed by detection of SARS-CoV-2 RNA in nasopharyngeal swab specimens. The 31 prevalence of SARS CoV-2 RNAemia and the strength of its association with clinical severity 32 variables were examined and included the need for transfer to an intensive care unit (ICU), 33 mechanical ventilation and 30-day all-cause mortality. 34 Results: Paired nasopharyngeal and plasma samples were included from 85 patients. The overall 35 median age was 55 years, and individuals with RNAemia were older than those with undetectable 36 SARS-CoV-2 RNA in plasma (63 vs 50 years; p=0.001). Comorbidities were frequent including 37 obesity (37.7%), hypertension (30.6%) and diabetes mellitus (22.4%). RNAemia was detected in 38 a total of 28/85 (32.9%) individual patients, including 22/28 (78.6%) who required hospital 39 admission. RNAemia was detected more frequently in individuals who developed severe disease 40 including the need for ICU transfer (32.1% vs 14.0%; p=0.05), mechanical ventilation (21.4% vs 41 3.5%; p=0.01) and 30-day all-cause mortality (14.3% vs 0%; p=0.01). No association was detected 42 between RNAemia and estimated levels of viral RNA in the nasopharynx. An additional 121 43 plasma samples from 28 individuals with RNAemia were assessed longitudinally, and RNA was 44 detected for a maximum duration of 10 days.45 All rights reserved. No reuse allowed without permission.was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Conclusion:This study demonstrated a high proportion of SARS-CoV-2 RNAemia, and an 46 association between RNAemia and clinical severity suggesting the potential utility of plasma viral 47 testing as a prognostic indicator for COVID-19. 48All rights reserved. No reuse allowed without permission.was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.(NP) swab samples. Preliminary data suggest that severe acute respiratory syndrome coronavirus 51 2 (SARS-CoV-2) RNA may also be detected in plasma and serum. 1,2 However, the frequency and 52 prognostic implication of viral RNA detection in these sample types is not fully understood. We 53 aim to investigate the association between detectable SARS-CoV-2 RNA in nasopharyngeal swab 54 and plasma samples, and to describe clinical implications of viral RNA detection in plasma. 55 56 Methods 57 We performed a cross-sectional study at the Stanford Health Care (SHC) Clinical Virology 58 Laboratory, which serves adult and pediatric tertiar...
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