Tweetorial on our recent study @LancetMicrobe in which we used the nasal innate immune response to find undiagnosed respiratory viruses. A thread (1/14)... thelancet.com/journals/lanmi… In many patients undergoing comprehensive viral PCR testing, no virus is ever found. While most of these folks have symptoms for another reason, we could be missing some viruses. But how to find them..? Our hospital has hundreds of virus-negative nasal swabs per week... (2/14)

Preprint on COVID human challenge study clarifies some much debated questions. This shows viral load by PCR (blue) and live virus (red) following infection - virus comes up first in throat but reaches higher level in nose. (1/4). researchsquare.com/article/rs-112… A positive rapid antigen test appears to be a pretty good reflection of live virus shedding (black bars) (2/4)

My first tweetorial! On our new #InnateImmunity and viral interference study @JExpMed. It started with puzzling observations that pointed to the importance of kinetics. We saw a robust interferon response in the upper airway in all COVID patients studied, mild and severe: ..But these samples were from different times in the disease course. To get at timing, we studied serial swabs from patients picked up early in infection, when the viral load was still going up. We measured virus and CXCL10, a biomarker of the interferon response…