Daniel Pan (University of Leicester)

Talk Title:  Rethinking Infectiousness Testing in Respiratory Virus Infections
Abstract: The current landscape in respiratory virus research focus predominantly on epidemiological and immunological markers of infection and disease severity, leaving the correlates of onward transmission poorly defined. Although viral culture remains the gold standard for infectiousness, it is neither rapid nor scalable, and lateral-flow assays—despite correlating well with culture—show diminishing real-world predictive power for identification of those transmit to others. Moreover, quantitative PCR of upper-respiratory specimens post-symptom onset fails to capture the predominantly presymptomatic window of highest infectiousness.
This talk posits that sampling exhaled breath, rather than swabbing the upper respiratory tract alone, provides a more accurate surrogate of host infectiousness. In Part I, I introduce a novel sampling tool, using modified duckbilled facemasks containing sampling strips that are able to capture and quantify exhaled virus (facemask sampling, FMS) and demonstrate, across multiple household transmission cohorts (2020–2024), that viral load from FMS associates more strongly with transmission compared to upper respiratory tract sampling (URTS); I further explore its kinetics during speech, singing, and how FMS viral load kinetics affect the symptoms of both index participants and contacts. Part II evaluates the feasibility and acceptability of routine FMS among healthcare workers, as well as the prevalence of asymptomatic healthcare workers breathing out respiratory viruses. In Part III, I integrate epidemiological and immunological analyses to show ongoing SARS-CoV-2 breakthrough infections in vaccinated staff, the absence of established immune correlates of transmission, and the broader impact of mask use on infection rates, mental health, and vaccine hesitancy. Together, these findings provide data to demonstrate FMS as a potential platform for scalable, real-time infectiousness testing with clinical and public-health implications.