1. Out today, an important study about the characteristics of 37 asymptomatic COVID-19 infections from Wuhan. Patients were identified by screening close contacts of the cases; the authors made every attempt to exclude mildly symptomatic infections. https://www.nature.com/articles/s41591-020-0965-6

2. One of the major findings of this paper is that asymptomatic patients "shed virus" longer—a median of 19 days—than symptomatic patients.

This deserves a caveat: "shed virus" here means test positive via RT-PCR nasal swab. We don't know for certain that this is live virus.

3. Over half of patients who were classified as asymptomatic based on the lack of any experienced symptoms showed abnormalities based on lung CT scans, indicating possible damage even in these patients.

4. The majority of asymptomatic patients develop antibodies against the disease, though IgG antibody levels are lower in asymptomatic patients than in symptomatic patients. Left: acute phase. Right: convalescent phase.

5. @florian_krammer noted an interesting discrepancy: though antibody levels are lower in asymptomatic patients, neutralizing antibody levels are *higher* in asymptomatics. I don't know what to make of this. https://twitter.com/florian_krammer/status/1273614229506048001

6. The study also found that asymptomatic patients show a lower inflammatory response, as measured by cytokine levels, than do symptomatic patients. This makes sense to me.