Can variants, reinfection, symptoms and test types affect COVID-19 diagnostic performance? A large-scale retrospective study of AG-RDTs during circulation of Delta and Omicron variants, Czechia, December 2021 to February 2022

Investor logo

Warning

This publication doesn't include Faculty of Arts. It includes Faculty of Medicine. Official publication website can be found on muni.cz.
Authors

KLIEGR Tomáš JARKOVSKÝ Jiří JIŘINCOVÁ Helena KUCHAŘ Jaroslav KAREL Tomáš CHUDÁN David VOJÍŘ Stanislav ZAVŘEL Michal ŠANCA Ondřej TACHEZY Ruth

Year of publication 2023
Type Article in Periodical
Magazine / Source EUROSURVEILLANCE
MU Faculty or unit

Faculty of Medicine

Citation
Web https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.38.2200938
Doi http://dx.doi.org/10.2807/1560-7917.ES.2023.28.38.2200938
Keywords SARS-CoV-2; delta; omicron; rapid antigen test; reinfection; vaccination
Attached files
Description BackgroundThe sensitivity and specificity of selected antigen detection rapid diagnostic tests (AG-RDTs) for SARS-CoV-2 were determined in the unvaccinated population when the Delta variant was circulating. Viral loads, dynamics, symptoms and tissue tropism differ between Omicron and Delta.AimWe aimed to compare AG-RDT sensitivity and specificity in selected subgroups during Omicron vs Delta circulation.MethodsWe retrospectively paired AG-RDT results with PCRs registered in Czechia's Information System for Infectious Diseases from 1 to 25 December 2021 (Delta, n = 20,121) and 20 January to 24 February 2022 (Omicron, n = 47,104).ResultsWhen confirmatory PCR was conducted on the same day as AG-RDT as a proxy for antigen testing close to peak viral load, the average sensitivity for Delta was 80.4% and for Omicron 81.4% (p < 0.05). Sensitivity in vaccinated individuals was lower for Omicron (OR = 0.94; 95% confidence interval (CI): 0.87-1.03), particularly in reinfections (OR = 0.83; 95% CI: 0.75-0.92). Saliva AG-RDT sensitivity was below average for both Delta (74.4%) and Omicron (78.4%). Tests on the European Union Category A list had higher sensitivity than tests in Category B. The highest sensitivity for Omicron (88.5%) was recorded for patients with loss of smell or taste, however, these symptoms were almost 10-fold less common than for Delta. The sensitivity of AG-RDTs performed on initially asymptomatic individuals done 1, 2 or 3 days before a positive PCR test was consistently lower for Omicron compared with Delta.ConclusionSensitivity for Omicron was lower in subgroups that may become more common if SARS-CoV-2 becomes an endemic virus.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.