Peak Nasal SARS-CoV-2 and Influenza Viral Loads Relative to Symptom Onset, 2022–2025: Impact of Vaccination and Implications for Multiplexed Testing

Key Points

• This research examines the timing of viral loads for SARS-CoV-2 and influenza relative to the onset of symptoms across different vaccination cohorts.
• Compared peak viral loads of SARS-CoV-2 and influenza across two cohorts (2022-23 and 2023-25)
• Analyzed the relationship between vaccination status and viral load timing
• Evaluated the timing of symptoms in relation to viral load peaks for influenza A and B
• SARS-CoV-2 viral loads peaked earlier in the 2023-25 cohort compared to the 2022-23 cohort
• Recent vaccinations were linked to delayed peak viral loads
• Influenza A reached peak viral loads at symptom onset while influenza B peaked four days into symptoms