Impact of SARS-CoV-2 Delta and Omicron variants on viral burden and cycle threshold in BNT162b2-vaccinated 12–18 years group

The SARS-CoV-2 pandemic continues to impact the medical, economic, social, and political areas worldwide. Although it has been claimed that children are the most responsible for the outbreaks as of September 2021, the statistics showed controversary. Although it showed no difference in viral load and Ct values between symptomatic children and symptomatic adults, or between asymptomatic children and asymptomatic adults, the molecular mechanism remains unclear. Here, we aimed to investigate the effects of different strains on infection by comparing viral load levels in pediatric patients aged 12–18 years, infected with different variants of SARS-CoV-2, and vaccinated with full-dose BNT162b2. In this retrospective study, a total of 200 patients aged 12–18 years, who were diagnosed with COVID-19 in our hospital, and vaccinated with full-dose BNT162b2, were analyzed according to their gender, age, viral load, and cycle threshold values. Viral RNA levels were evaluated using Ct values, a semi-quantitative proxy of viral load. While the findings did not show a significant difference between gender and age ( P = 0.886 and P = 0.897, respectively), a significant difference was found between the Ct and viral load ( P