Safety, tolerability and viral kinetics during SARS-CoV-2 human challenge in young adults

Abstract

oronavirus disease 2019 (COVID-19) is a complex clinical syndrome caused by SARS-CoV-2. Despite extensive research into severe disease of hospitalized patients 1 and many large studies leading to approval of vaccines and antivirals 2-4 , the global spread of SARS-CoV-2 continues and is, indeed, accelerating in many regions. Infections are typically mild or asymptomatic in younger people, but these likely drive community transmission 5 , and the detailed time course of infection and infectivity in this context has not been fully elucidated 6,7 . Deliberate human infection of low-risk volunteers enables the exact longitudinal measurement of viral kinetics, immunological responses, transmission dynamics and duration of infectious shedding after a fixed dose of

Dose-response modelling of endemic coronavirus and SARS-CoV-2: human challenge trials reveal the individual variation in susceptibility

“…In the available human challenge study with SARS-CoV-2 all participants were healthy young adults with no evidence of previous SARS-CoV-2 infection or vaccination, and they were all exposed to the same single dose [10]. Here we show how the variation in susceptibility would affect the infection risk at different doses.…”

Surface detection of SARS-CoV-2 by lateral flow LAMP

“…This method is attractive as an early-warning monitor when cohorts of humans can be tested anonymously (such as high-touch surfaces in shared apartment buildings or dorm rooms, currency, or wastewater). Given that an infected individual may harbor 10 9 viral particles per mL in their airway [22], it is reasonable to estimate that one infected person could deposit 5 x10 6 particles on a surface (as in Fig. 5) in only a few microliters of saliva.…”

Diagnostic strategy of SARS-CoV-2 for containment under China's zero-COVID-19 policy

“…Although the earlier cases with infection over 14 days might be missed both the first self-RAT and RT-qPCR tests, they either had very low viral load, or had returned to be negative, and were unable to or very less likely spread the virus. 8 The cases C11 and newly infected individuals N1-N5, as well as any cases during transmission window (high viral load > 10e4-5 copies/mL) but missed by both the first self-RAT and RT-qPCR tests, can be found by subsequent self-RAT and RT-qPCR tests. In theory, under strict community closed-off management, the vast majority of infected cases can be effectively found and quarantined after three rounds (about two weeks) of broad RT-qPCR and multiplex times of self-RAT screenings.…”

“…1 ). 8 Infected individuals remain high level of viral load (>10e4-5 copies/mL), and are ready to spread the virus to other people during 3-9 days of infection, 8 , 9 which is called transmission window ( Fig. 1 ).…”

“…Colored lines shows the viral load dynamics of individuals infected by SARS-CoV-2 at different time-points. The curves were drawn based on the data from ref 8 . The detection lines of both RAT and RT-qPCR assays are shown by colored thick lines.…”