Comparison of Cycle Threshold and Clinical Status Among Different Age Groups of COVID-19 Cases

Abstract

Introduction The COVID-19 pandemic has shaken the entire world ever since its emergence in March 2020. The disease manifestation of COVID-19 has been more severe, with a high degree of mortality in the elderly than in the young population. The cycle threshold (Ct ) value obtained in the real-time polymerase chain reaction (RT-PCR) has been used as the surrogate marker of viral load. Therefore, assessing Ct value and clinical status among different age groups with SARS-CoV-2 infection is required to understand the viral kinetics and to assess the transmission potential of that particular age group. Purpose The aim of this study was to compare the viral load and clinical status among different age groups with COVID-19 infection. Methods and materials A retrospective cross-sectional study was carried out to analyze the Ct values of SARS-CoV-2 positive samples reported from April 2020 till May 2021. The results of 13,820 RT-PCR (reverse transcriptase-polymerase chain reaction) positive samples were included for analysis of Ct values. Ct values of confirmatory genes were taken into consideration, and Ct values below 25, >25 to 30, and >30 were categorized as high, moderate, and low viral load, respectively. Age group was stratified into ≤18 years (young), 18-60 years (adult), and >60 years (elderly). The data were analyzed using SPSS Windows Version 25.0. Results The mean Ct values were 27.9, 26, and 26.2 in the young, adult, and elderly age groups, respectively. The mean Ct values of young patients were significantly higher as compared to adult and elderly patients (p<0.05). The percentage of high viral load (Ct<25) was found to be significantly higher in adults and elderly (44.6% & 43.7%) as compared to young (32.2%) (p<0.001). Majority of the COVID-19 positive cases younger than 18 years (75.9%) were asymptomatic as compared to 64.5% and 59.7% in the adult and elderly age groups, respectively. Conclusion This study observed a significantly high proportion of viral load in the adult and elderly population, which plays a substantial contribution to SARS-CoV-2 transmission, whereas the majority of the young population being asymptomatic plays a major role as silent transmitters. The study reemphasizes the need for strict adherence to COVID-appropriate behaviors.

Impact of SARS-CoV-2 RNA titer on the level of IgG antibodies in recovered patients with COVID-19 disease

“…Some studies have found a similar demonstration of Ct values. Maltezou et al, [18]-in Greece and Mishra et al [19] in India found lower Ct values in older people than younger ones while other studies demonstrated higher Ct values among patients older than 80 years old [20].…”

“…Coronaviruses have existed and replicated for thousands of years and continue to do so [1]. The virus SARS coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID- 19), resulted in a worldwide pandemic [2]. Globally, as of 17 June 2022, the confirmed cases of COVID-19 were 535,863,950, with 6,314,972 estimated deaths, and the number of vaccine doses administered has reached 11,902,271,619 according to WHO.…”

Using Real-Time PCR Fluorescence Reaction Values to Improve SARS-CoV-2 Virus Detection and Benefit Clinical Decision-Making

“…AlBahrani et al reported that SARS-CoV-2 Ct values do not show any association with clinical symptoms and do not predict the need for mechanical intubation or death [ 21 ]. Another study showed that gender, age, co-morbidity, and mortality do not differ significantly between patients with low (≤25) and those with high (>25) Ct values [ 22 ]. However, in Coyle et al’s study, Ct ≤ 30 was reported as positive and Ct > 30 as reactive and interpretive comments were added to all reports; these reports had an impact on patient and public health management criteria [ 23 ].…”

An AIEgen/graphene oxide nanocomposite (AIEgen@GO)‐based two‐stage “turn‐on” nucleic acid biosensor for rapid detection of SARS‐CoV‐2 viral sequence

“…Currently, the gold standard for COVID-19 diagnostics is RT-qPCR, which has been utilized to detect SARS-CoV-2 viral load in clinical samples. [50][51][52] The cycle threshold (Ct) value measured by RT-qPCR is a clinical indicator of a detectable amount of SARS-CoV-2 virus in the RT-qPCR experiment, which has an inverse relationship with the viral load. [49] According to the literature, the Ct values of SARS-CoV-2 virus with N and Orf1ab as primary markers of SARS-CoV-2 in clinical samples ranged from around 10 to 37.…”