Clinical Performance of a Standardized Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Interferon-γ Release Assay for Simple Detection of T-Cell Responses After Infection or Vaccination.

BACKGROUND: We evaluated a standardized interferon-γ (IFN-γ) release assay (IGRA) for detection of T-cell immune response after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination. METHODS: This prospective study included patients with coronavirus disease 2019 (COVID-19) with different severity of illness and follow-up (FU), vaccinated subjects, and healthy unvaccinated persons. SARS-CoV-2 T-cell response was measured using a specific quantitative IGRA in whole blood (Euroimmun, Germany) and TrimericS-IgG and neutralizing antibodies with validated serological platforms. Positivity of reverse transcription-polymerase chain reaction or vaccination was considered as the reference standard. RESULTS: A total of 239 individuals were included (152 convalescent, 54 vaccinated, and 33 uninfected unvaccinated). Overall sensitivity, specificity, and positive- and negative-predictive values (95% confidence interval) of the IGRA were 81.1% (74.9-86%), 90.9% (74.5-97.6%), 98.2% (94.5-99.5%), and 43.5% (31.8-55.9%), respectively. All vaccinated SARS-CoV-2-naive subjects had positive IGRA at 3 months. In convalescent subjects the magnitude of IFN-γ responses and IGRA accuracy varied according to disease severity and duration of FU, with the best performance in patients with severe COVID-19 at 3 months and the worst in those with mild disease at 12 months. The greatest contribution of IGRA to serological tests was observed in patients with mild disease and long-term FU (incremental difference, 30.4%). CONCLUSIONS: The IGRA was a reliable method of quantifying T-cell response after SARS-COV-2 infection or vaccination. In convalescent patients, the sensitivity is largely dependent on disease severity and time since primary infection. The assay is more likely to add clinical value to serology in patients with mild infections.

SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders.

BACKGROUND: The clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has not yet been established. PATIENTS AND METHODS: A prospective multicenter registry-based cohort study conducted from December 2020 to December 2021 by the Spanish transplant and cell therapy group was used to analyze the relationship of antibody response at 3-6 weeks after full vaccination (2 doses) with breakthrough SARS-CoV-2 infection in 1394 patients with hematological disorders. RESULTS: At a median follow-up of 165 days after complete immunization, 37 out of 1394 (2.6%) developed breakthrough SARS-CoV-2 infection at median of 77 days (range 7-195) after full vaccination. The incidence rate was 6.39 per 100 persons-year. Most patients were asymptomatic (19/37, 51.4%), whereas only 19% developed pneumonia. The mortality rate was 8%. Lack of detectable antibodies at 3-6 weeks after full vaccination was the only variable associated with breakthrough infection in multivariate logistic regression analysis (Odds Ratio 2.35, 95% confidence interval 1.2-4.6, p = 0.012). Median antibody titers were lower in cases than in non-cases [1.83 binding antibody units (BAU)/mL (range 0-4854.93) vs 730.81 BAU/mL (range 0-56,800), respectively (p = 0.007)]. We identified 250 BAU/mL as a cutoff above which incidence and severity of the infection were significantly lower. CONCLUSIONS: Our study highlights the benefit of developing an antibody response in these highly immunosuppressed patients. Level of antibody titers at 3 to 6 weeks after 2-dose vaccination links with protection against both breakthrough infection and severe disease for non-Omicron SARS-CoV-2 variants.

SARS-CoV-2-reactive antibody detection after SARS-CoV-2 vaccination in hematopoietic stem cell transplant recipients: Prospective survey from the Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group.

This is a multicenter prospective observational study that included a large cohort (n = 397) of allogeneic (allo-HSCT; (n = 311) and autologous (ASCT) hematopoietic stem cell transplant (n = 86) recipients who were monitored for antibody detection within 3-6 weeks after complete severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination from February 1, 2021, to July 20, 2021. Most patients (n = 387, 97.4%) received mRNA-based vaccines. Most of the recipients (93%) were vaccinated more than 1 year after transplant. Detectable SARS-CoV-2-reactive antibodies were observed in 242 (78%) of allo-HSCT and in 73 (85%) of ASCT recipients. Multivariate analysis in allo-HSCT recipients identified lymphopenia < 1 × 109 /ml (odds ratio [OR] 0.33, 95% confidence interval [95% CI] 0.16-0.69, p = .003), active graft versus host disease (GvHD; OR 0.51, 95% CI 0.27-0.98, p = .04) and vaccination within the first year of transplant (OR 0.3, 95% CI 0.15-0.9, p = .04) associated with lower antibody detection whereas. In ASCT, non-Hodgkin's lymphoma (NHL; OR 0.09, 95% CI 0.02-0.44, p = .003) and active corticosteroid therapy (OR 0.2, 95% CI 0.02-0.87, p = .03) were associated with lower detection rate. We report an encouraging rate of SARS-CoV-2-reactive antibodies detection in these severe immunocompromised patients. Lymphopenia, GvHD, the timing of vaccine, and NHL and corticosteroids therapy should be considered in allo-HSCT and ASCT, respectively, to identify candidates for SARS-CoV-2 antibodies monitoring.

Late reinfection with a different severe acute respiratory syndrome coronavirus-2 clade in a patient with refractory arterial hypertension: a case report.

BACKGROUND: Differentiating between persistent infection with intermittent viral shedding and reinfection with severe acute respiratory syndrome coronavirus 2 remains challenging. Although a small number of cases with genomic evidence of second infection have been reported, limited information exists on frequency and determinants of reinfection, time between infections, and duration of immunity after the primary infection. CASE PRESENTATION: We report a reinfection with severe acute respiratory syndrome coronavirus 2 in a 52-year-old caucasian male whose primary infection was diagnosed in May 2020, during the first wave of the pandemic in Spain, and the second occurred 8 months later, in January 2021. We present a complete dataset including results from real-time polymerase chain reaction, serology, and genome sequencing confirming reinfection with a different clade. Noteworthy was that the patient was immunocompetent but had multiple cardiometabolic comorbidities, including refractory arterial hypertension, that might increase the individual risk in coronavirus disease 2019. CONCLUSIONS: This case of reinfection with severe acute respiratory syndrome coronavirus 2 occurring several months after the primary infection reports the longest time interval between reinfection and initial infection described to date. It raises concerns on the duration of protective immunity, suggesting that it may begin to wane in patients who acquired the initial infection during the first wave of the pandemic. The potential contributing role of arterial hypertension and cardiometabolic comorbidities as risk factors for reinfection deserves investigation.

Performance of Saliva Specimens for the Molecular Detection of SARS-CoV-2 in the Community Setting: Does Sample Collection Method Matter?

Data on the performance of saliva specimens for diagnosing coronavirus disease 2019 (COVID-19) in ambulatory patients are scarce and inconsistent. We assessed saliva-based specimens for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse transcriptase PCR (RT-PCR) in the community setting and compared three different collection methods. This prospective study was conducted in three primary care centers. RT-PCR was performed on paired nasopharyngeal swabs (NPS) and saliva samples collected from outpatients with a broad clinical spectrum of illness. To assess differences in collection methods, saliva specimens were obtained in a different way in each of the participating centers: supervised collection (SVC), oropharyngeal washing (OPW), and self-collection (SC). Pairs of NPS and saliva samples from 577 patients (median age, 39 years; 44% men; 42% asymptomatic) were collected and tested, and 120 (20.8%) gave positive results. The overall agreement with NPS results and kappa coefficients (κ) for saliva samples obtained by SVC, OPW, and SC were 95% (κ = 0.85), 93.4% (κ = 0.76), and 93.3% (κ = 0.76), respectively. The sensitivities (95% confidence intervals [95% CI]) of the saliva specimens ranged from 86% (72.6% to 93.7%) for SVC to 66.7% (50.4% to 80%) for SC samples. Sensitivity was higher for samples with lower cycle threshold (CT ) values. The best RT-PCR performance was observed for SVC, with sensitivities (95% CI) of 100% (85.9% to 100%) in symptomatic individuals and 88.9% (50.7% to 99.4%) in asymptomatic individuals at CT values of ≤30. We conclude that saliva is an acceptable specimen for the detection of SARS-CoV-2 in the community setting. Specimens collected under supervision perform comparably to NPS and can effectively identify individuals at higher risk of transmission under real-life conditions.

Asthma prevalence in patients with SARS-CoV-2 infection detected by RT-PCR not requiring hospitalization.

INTRODUCTION: The prevalence of asthma in patients hospitalized with SARS-CoV-2 has been studied and varies widely in the different series. However, the prevalence in SARS-infected patients not requiring hospitalization is not known. The objective of this study was to analyze the presence of asthma in a consecutive series of patients who tested positive in the RT-PCR assay for SARS-CoV-2 and did not require hospital admission. METHODS AND RESULTS: A total of 218 patients (58% of those who tested positive) did not require hospitalization; they had a median age of 45 years (IQR 34-57) and 57% were female. Six patients (2.8%) had a previous diagnosis of asthma. Only one patient developed a mild aggravation of asthma symptoms associated with SARS-CoV-2 infection. CONCLUSIONS: Few patients with asthma were infected by SARS-CoV-2, and this infection was not a significant cause of asthma exacerbation.