1/ In new preprint w/ @AaronRichterman @mugecevik @BogochIsaac @nicolamlow we argue limitations to understanding true asymptomatic fraction:
1) Inconsistent sx reporting
2) Inadequate f/u time to exclude "pre-symptomatic" ppl
3) Issues w/ serosurveys
papers.ssrn.com/sol3/papers.cf…
1) Inconsistent sx reporting
2) Inadequate f/u time to exclude "pre-symptomatic" ppl
3) Issues w/ serosurveys
papers.ssrn.com/sol3/papers.cf…
2/ Wide range of asymptomatic proportion reported in the literature from 4% to >80%. Systematic reviews provide best estimates and suggest values closer to 20% medrxiv.org/content/10.110…
3/ Our understanding of the symptom spectrum of SARS-CoV-2 infection has evolved over the last 9 months, with anosmia and GI symptoms often not included in early reports. By not including these mild or atypical symptoms, the estimated asymptomatic fraction may be overestimated
4/ Cross-sectional studies or studies without at least 14-days of prospective follow up may misclassify pre-symptomatic patients as asymptomatic
5/ Serostudies are an attractive theorized way to estimate asymptomatic cases but antibody test characteristics are defined in PCR positive individuals and detectable antibody levels wane quickly in asymptomatic or mild cases
6/ Poor understanding of the asymptomatic fraction limits optimal public health response. Transmission potential of asymptomatic individuals is poorly understood. There are differing reports of the relative duration of viral shedding for asymptomatic cases
7/ By understanding the true asymptomatic fraction, we may improve contact tracing strategy, learn about COVID-19 pathogenesis and better understand the vast illness severity spectrum
