A considerable proportion of individuals with asymptomatic SARS-CoV-2 infection in Tibetan population

Abstract

medRxiv preprintSevere acute respiratory syndrome coronavirus 2 (SARS-Cov-2) quickly became a major epidemic threat in the whole China. We analysed SARS-Cov-2 infected cases from Tibetan Autonomous Prefecture, and noted divergent characteristics of these Tibetans infected cases compared to Han Chinese, characterizing by a considerable proportion of asymptomatic carriers (21.7%), and few symptomatic patients with initial symptom of fever (7.7%). Here, we did a descriptive study on clinical characteristics of 18 asymptomatic individuals with SARS-CoV-2 infection. The median age of these asymptomatic carriers was 31 years and one third of them were students, aged under 20 years. Notably, some of asymptomatic carriers had recognizable changes in radiological and laboratory indexes. Our finding indicates a potentially big number of SARS-CoV-2 asymptomatic carriers in prevalent area, highlighting a necessity of screening individuals with close contact of infected patients, for a better control on the spread of SARS-CoV-2 infection.

Estimation of the basic reproduction number, average incubation time, asymptomatic infection rate, and case fatality rate for COVID-19: Meta-analysis and sensitivity analysis

“…Ruan [13] up to Mar 21, 2020 Mar 13-20, 2020 13 long-term care residents in King County, Washington Song et al [22] followed up until Mar 6, 2020 retrospective single-centre study in Daofu county, Sichuan…”

“…Finally, we are interested in estimating the case fatality rate which measures how deadly COVID-19 is for the infected people. The meta-analysis results derived from seven studies available in the literature, shown in the top panel of Figure 4, are reported at the bottom Study Nishiura et al [20] Kimball et al [21] Song et al [22] Mizunoto et al [23] Serra [24] Day [25] Summary (Random) Figure 4, where we assume the random effect models because the I 2 index is 99.5%. The estimated case fatality rate is 3.34%, slightly smaller than 3.4%, the estimate reported on March 3, 2020 by the WHO [2].…”

“…Nishiura et al [20] Kimball et al [21] Song et al [22] Mizunoto et al [23] Serra [24] Day [25] Meta−Random portion of asymptomatic infections are not counted when estimating the case fatality rate. Our sensitivity study addresses this important issue and makes an adjustment to provide a sensible estimate of the case fatality rate.…”

The impact of long-term non-pharmaceutical interventions on COVID-19 epidemic dynamics and control

“…ever, many currently available epidemiological models are not set up for other scientists or policymakers 23 to conveniently explore a variety of exit strategies for specific locations to which the model is also fit. 24 We developed an epidemiological compartment model of COVID-19 dynamics that uses a time-varying 25 transmission parameter, β, to investigate the impact of non-pharmaceutical interventions on epidemic dy- 26 namics and control. The model incorporates transmission from both asymptomatic and presymptomatic 27 infectious people.…”

Overview of COVID‐19 testing and implications for otolaryngologists

“…13 Notably, emerging data has found the asymptomatic carrier rate to be in the range of 17.9% to 21.7%. 14,15 The most common laboratory abnormalities included lymphocytopenia (83.2%), thrombocytopenia (36.2%), and leukopenia (33.7%). 10…”