Total and subgenomic RNA viral load in patients infected with SARS-CoV-2 Alpha, Delta, and Omicron variants
Author Department
Medicine
Document Type
Article, Peer-reviewed
Publication Date
3-2023
Abstract
Background: SARS-CoV-2 genomic and subgenomic RNA levels are frequently used as a correlate of infectiousness. The impact of host factors and SARS-CoV-2 lineage on RNA viral load is unclear.
Methods: Total nucleocapsid (N) and subgenomic N (sgN) RNA levels were measured by RT-qPCR in specimens from 3,204 individuals hospitalized with COVID-19 at 21 hospitals. RT-qPCR cycle threshold (Ct) values were used to estimate RNA viral load. The impact of time of sampling, SARS-CoV-2 variant, age, comorbidities, vaccination, and immune status on N and sgN Ct values were evaluated using multiple linear regression.
Results: Ct values at presentation for N (mean ±standard deviation) were 24.14±4.53 for non-variants of concern, 25.15±4.33 for Alpha, 25.31±4.50 for Delta, and 26.26±4.42 for Omicron. N and sgN RNA levels varied with time since symptom onset and infecting variant but not with age, comorbidity, immune status, or vaccination. When normalized to total N RNA, sgN levels were similar across all variants.
Conclusions: RNA viral loads were similar among hospitalized adults, irrespective of infecting variant and known risk factors for severe COVID-19. Total N and subgenomic RNA N viral loads were highly correlated, suggesting that subgenomic RNA measurements adds little information for the purposes of estimating infectivity.
Keywords: SARS-CoV-2; subgenomic RNA; variants of concern; viral load.
Recommended Citation
Dimcheff DE, Blair CN, Zhu Y, Chappell JD, Gaglani M, McNeal T, Ghamande S, Steingrub JS, Shapiro NI, Duggal A, Busse LW, Frosch AEP, Peltan ID, Hager DN, Gong MN, Exline MC, Khan A, Wilson JG, Qadir N, Ginde AA, Douin DJ, Mohr NM, Mallow C, Martin ET, Johnson NJ, Casey JD, Stubblefield WB, Gibbs KW, Kwon JH, Talbot HK, Halasa N, Grijalva CG, Baughman A, Womack KN, Hart KW, Swan SA, Surie D, Thornburg NJ, McMorrow ML, Self WH, Lauring AS; Investigating Respiratory Viruses in the Acutely Ill (IVY) Network. Total and subgenomic RNA viral load in patients infected with SARS-CoV-2 Alpha, Delta, and Omicron variants. J Infect Dis. 2023 Mar 8:jiad061. doi: 10.1093/infdis/jiad061. Epub ahead of print.
PMID
36883903