Evaluation of four laboratory-based high-throughput SARS-CoV-2 automated antigen tests compared to RT-PCR on nasal and oropharyngeal samples.

BACKGROUND: The demand for RT-PCR testing has been unprecedented during the SARS-CoV-2 pandemic. Fully automated antigen tests (AAT) are less cumbersome than RT-PCR, but data on performance compared to RT-PCR are scarce. METHODS: The study consists of two parts. A retrospective analytical part, comparing the performance of four different AAT on 100 negative and 204 RT-PCR positive deep oropharyngeal samples divided into four groups based on RT-PCR cycle of quantification levels. In the prospective clinical part, 206 individuals positive for and 199 individuals negative for SARS-CoV-2 were sampled from either the anterior nasal cavity (mid-turbinate) or by deep oropharyngeal swabs or both. The performance of AATs was compared to RT-PCR. RESULTS: The overall analytical sensitivity of the AATs differed significantly from 42% (95% CI 35-49) to 60% (95% CI 53-67) with 100% analytical specificity. Clinical sensitivity of the AATs differed significantly from 26% (95% CI 20-32) to 88% (95% CI 84-93) with significant higher sensitivity for mid-turbinate nasal swabs compared to deep oropharyngeal swabs. Clinical specificity varied from 97% to 100%. CONCLUSION: All AATs were highly specific for detection of SARS-CoV-2. Three of the four AATs were significantly more sensitive than the fourth AAT both in terms of analytical and clinical sensitivity. Anatomical test location significantly influenced the clinical sensitivity of AATs.

Lung Abnormalities in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: An Analysis of Paired Computed Tomography Scans Before and After Infection.

Background: Studies on the pulmonary consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are impeded by limited access to pre-SARS-CoV-2 examinations. Methods: We invited Copenhagen General Population Study participants with a confirmed SARS-CoV-2 polymerase chain reaction (PCR) test during the first and second coronavirus disease 2019 waves in Denmark for a repeat chest computed tomography (CT) scan. Paired CT scans were independently assessed for interstitial and noninterstitial abnormalities by 2 trained radiologists. A semiquantitative CT score (ranging from 0 to 20) was used to quantify the extent of interstitial abnormalities. Results: Of 111 SARS-CoV-2-infected individuals, 102 (91.2%) experienced symptoms and 12 (11.2%) were hospitalized. Follow-up examination was performed at median of 5.4 (interquartile range, 4.1-7.8) months after a positive SARS-CoV-2 PCR test. Of 67 individuals with paired CT scans, ground glass opacities and reticulation were present in 31 (46.3%) individuals post-SARS-CoV-2 compared to 23 (34.1%) pre-SARS-CoV-2 (mean CT score, 3.0 vs 1.3; P = .011). Results were similar for nonhospitalized individuals. We did not detect development of bronchiectasis, emphysema, or nodules. Conclusions: SARS-CoV-2 infection in predominantly nonhospitalized individuals with mild disease was associated with a small increase in only interstitial lung abnormalities.

Lung Function Decline in Relation to COVID-19 in the General Population: A Matched Cohort Study With Prepandemic Assessment of Lung Function.

BACKGROUND: To quantify the potential decline in dynamic lung volumes following coronavirus disease 2019 (COVID-19) in the general population. METHODS: A prospective matched cohort study of adult Copenhagen General Population Study (CGPS) participants with a prepandemic spirometry available. CGPS individuals with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) test performed repeat spirometry, a questionnaire regarding respiratory symptoms, and diffusing capacity test for carbon monoxide. A matched uninfected CGPS control sample was used, and simple regression and linear mixed effect models were computed to study lung function decline. RESULTS: A total of 606 individuals were included; 92/107 (85.9%) with positive SARS-CoV-2 PCR test experienced coronavirus disease 2019 (COVID-19) symptoms and 12 (11.2%) were hospitalized. Spirometry was performed at median 5.6 months (interquartile range, 3.9-12.8) after positive SARS-CoV-2 PCR test. COVID-19 was associated with adjusted 7.3 mL (95% confidence interval [CI], .3-14.3) and 22.6 mL (95% CI, 13.1-32.0) steeper decline in annual forced expiratory volume in first second (FEV1) and FVC or total 113.8 and 301.3 mL lower FEV1 and FVC from baseline to follow-up. Results were robust in analyses restricted to individuals not requiring hospitalization. CONCLUSIONS: COVID-19-related declines of dynamic lung volume in the general population not requiring hospitalization were small but measurable.

Comparison of 16 Serological SARS-CoV-2 Immunoassays in 16 Clinical Laboratories.

Serological assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to support clinical diagnosis and epidemiological investigations. Recently, assays for large-scale detection of total antibodies (Ab), immunoglobulin G (IgG), and IgM against SARS-CoV-2 antigens have been developed, but there are limited data on the diagnostic accuracy of these assays. This study was a Danish national collaboration and evaluated 15 commercial and one in-house anti-SARS-CoV-2 assays in 16 laboratories. Sensitivity was evaluated using 150 samples from individuals with asymptomatic, mild, or moderate COVID-19, nonhospitalized or hospitalized, confirmed by nucleic acid amplification tests (NAAT); samples were collected 13 to 73 days either from symptom onset or from positive NAAT (patients without symptoms). Specificity and cross-reactivity were evaluated in samples collected prior to the SARS-CoV-2 epidemic from >586 blood donors and patients with autoimmune diseases, cytomegalovirus or Epstein-Barr virus infections, and acute viral infections. A specificity of ≥99% was achieved by all total-Ab and IgG assays except one, DiaSorin Liaison XL IgG (97.2%). Sensitivities in descending order were Wantai ELISA total Ab (96.7%), CUH-NOVO in-house ELISA total Ab (96.0%), Ortho Vitros total Ab (95.3%), YHLO iFlash IgG (94.0%), Ortho Vitros IgG (93.3%), Siemens Atellica total Ab (93.2%), Roche Elecsys total Ab (92.7%), Abbott Architect IgG (90.0%), Abbott Alinity IgG (median 88.0%), DiaSorin Liaison XL IgG (median 84.6%), Siemens Vista total Ab (81.0%), Euroimmun/ELISA IgG (78.0%), and Snibe Maglumi IgG (median 78.0%). However, confidence intervals overlapped for several assays. The IgM results were variable, with the Wantai IgM ELISA showing the highest sensitivity (82.7%) and specificity (99%). The rate of seropositivity increased with time from symptom onset and symptom severity.