The Association Between the Ct Value of SARS-CoV-2 and the Risk of Death from COVID-19 in Amazonas, Peru, During the Circulation of the Lambda, Gamma, and Delta Variants

This study aimed to assess the association between the cycle threshold (Ct) values of SARS-CoV-2 and the risk of death from COVID-19 in adult patients from the Amazonas region of Peru during the circulation of the Lambda, Gamma, and Delta variants. The study population included both hospitalized and outpatient patients, symptomatic and asymptomatic, between August 2020 and August 2021. The standardized Ct values of the ORF1ab gene were categorized into low and high Ct groups based on the median Ct value (28.4). Mortality data within 60 days were obtained from the Peruvian epidemiological surveillance system (Notiweb). The risk of death was estimated using Cox regression, adjusting for relevant predictors and potential confounding variables. Among symptomatic COVID-19 patients, no significant difference in the risk of death was observed between those with low and high Ct values (adjusted hazard ratio [aHR] = 1.61; 95% confidence interval [CI], 0.97-2.67; <i>p</i> = 0.067). However, hospitalized patients with low Ct values had a significantly higher risk of death compared to those with high Ct values (aHR = 1.82; 95% CI, 1.06-3.12; <i>p</i> = 0.030). This association persisted after adjusting for age, sex, occupational group, symptom duration, comorbidities, and epidemic dynamics. In conclusion, while Ct values in symptomatic COVID-19 patients (both hospitalized and outpatient) are not associated with a 60-day mortality risk, a low Ct value is linked to an increased risk of death in hospitalized patients.