SARS-CoV-2, SARS-CoV-1 and MERS-CoV Viral Load Dynamics, Duration of Viral Shedding and Infectiousness: A Living Systematic Review and Meta-Analysis

Çevik, Müge; Tate, Matthew; Lloyd, Oliver; Maraolo, Alberto Enrico; Schafers, Jenna; Ho, Antonia

doi:10.2139/ssrn.3677918

Cited by 54 publications

(45 citation statements)

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“…As transmission may increase with viral load in the LRT (27) and such severe manifestations will necessarily curtail transmission, this provides another way by which the virulence transmission trade-off could manifest. Conversely, however, more severe cases are associated with prolonged shedding (30) (the opposite of the expected relationship), severity may manifest after the point where viral load is high enough to allow transmission (30) thus removing the impact of virulence per se on onward transmission (31), and the relationship between viral load and onward transmission may be relatively weak (e.g., flat at some scales (27)), all of which suggests a trade-off might not exist. These incomplete threads of evidence preclude definitive conclusions about the existence or shape of a relationship between transmission and virulence, although the within-host dynamics of SARS-CoV-2 infection remain an area of intense research focus, and future findings could resolve the current uncertainty.…”

Section: Association Between Transmission and Virulencementioning

confidence: 99%

Assessing the risk of vaccine-driven virulence evolution in SARS-CoV-2

Miller

Metcalf

2020

Preprint

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Vaccines that reduce clinical severity but not infection or transmission could drive the evolution of increased rates of pathogen-inflicted damage, or virulence. Preliminary evidence suggests that COVID-19 vaccines might have such differential effects, conferring greater protection in the lower respiratory tract, where viral growth most impacts severity, than in the upper respiratory tract, where infection is chiefly determined. However, the evolution of increased virulence can only occur under certain conditions, which include the existence of a positive association between transmission and severity linked to viral genetic variation. Here, we review the current evidence for these conditions, which does not point to a risk of vaccine driven virulence evolution. An evo-epidemiological model also indicates that upper respiratory tract protection can minimize or negate selection for increased virulence should these conditions be met. Despite low apparent risks, SARS-CoV-2 virulence should be monitored, and transmission-limiting characteristics should be prioritized for ‘second-wave’ vaccines.

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Section: Association Between Transmission and Virulencementioning

confidence: 99%

Assessing the risk of vaccine-driven virulence evolution in SARS-CoV-2

Miller

Metcalf

2020

Preprint

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“…Distribution of mean and maximum recorded shedding periods for SARS-CoV-2 and other respiratory viruses after disease onset. Mean durations of SARs-CoV-2 shedding by PCR in 31 published larger cohort studies (total subjects=4150) [2, 37, 90–97] compared to those of RSV and IAV [1, 7–14]. Solid black lines indicate the mean value of all studies for each virus.…”

Section: The Acute Infection Modelmentioning

confidence: 99%

Understanding the outcomes of COVID-19 – does the current model of an acute respiratory infection really fit?

Simmonds

Williams

Harvala

2021

Journal of General Virology

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Although coronavirus disease 2019 (COVID-19) is regarded as an acute, resolving infection followed by the development of protective immunity, recent systematic literature review documents evidence for often highly prolonged shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory and faecal samples, periodic recurrence of PCR positivity in a substantial proportion of individuals and increasingly documented instances of reinfection associated with a lack of protective immunity. This pattern of infection is quite distinct from the acute/resolving nature of other human pathogenic respiratory viruses, such as influenza A virus and respiratory syncytial virus. Prolonged shedding of SARS-CoV-2 furthermore occurs irrespective of disease severity or development of virus-neutralizing antibodies. SARS-CoV-2 possesses an intensely structured RNA genome, an attribute shared with other human and veterinary coronaviruses and with other mammalian RNA viruses such as hepatitis C virus. These are capable of long-term persistence, possibly through poorly understood RNA structure-mediated effects on innate and adaptive host immune responses. The assumption that resolution of COVID-19 and the appearance of anti-SARS-CoV-2 IgG antibodies represents virus clearance and protection from reinfection, implicit for example in the susceptible–infected–recovered (SIR) model used for epidemic prediction, should be rigorously re-evaluated.

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“…Several studies reported that on average the duration of viral particle shedding from the upper airway is~17 days, the lower respiratory tract~15 days, feces~13 days, and blood~17 days (reviewed in ref. [124]). The longest durations reported to date for detection of viral RNA were 83 days, 59 days, 126 days, and 60 days in the upper airway, the lower respiratory tract, feces, and blood, respectively [124,125].…”

Section: Viral Dynamics and Duration Of Infectiousnessmentioning

confidence: 99%

Insights into SARS-CoV-2 Persistence and Its Relevance

Desimmie

Raru

Awadh

et al. 2021

Viruses

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), continues to wreak havoc, threatening the public health services and imposing economic collapse worldwide. Tailoring public health responses to the SARS-CoV-2 pandemic depends on understanding the mechanism of viral replication, disease pathogenesis, accurately identifying acute infections, and mapping the spreading risk of hotspots across the globe. However, effective identification and isolation of persons with asymptomatic and mild SARS-CoV-2 infections remain the major obstacles to efforts in controlling the SARS-CoV-2 spread and hence the pandemic. Understanding the mechanism of persistent viral shedding, reinfection, and the post-acute sequalae of SARS-CoV-2 infection (PASC) is crucial in our efforts to combat the pandemic and provide better care and rehabilitation to survivors. Here, we present a living literature review (January 2020 through 15 March 2021) on SARS-CoV-2 viral persistence, reinfection, and PASC. We also highlight potential areas of research to uncover putative links between viral persistence, intra-host evolution, host immune status, and protective immunity to guide and direct future basic science and clinical research priorities.

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SARS-CoV-2, SARS-CoV-1 and MERS-CoV Viral Load Dynamics, Duration of Viral Shedding and Infectiousness: A Living Systematic Review and Meta-Analysis

Cited by 54 publications

References 0 publications

Assessing the risk of vaccine-driven virulence evolution in SARS-CoV-2

Assessing the risk of vaccine-driven virulence evolution in SARS-CoV-2

Understanding the outcomes of COVID-19 – does the current model of an acute respiratory infection really fit?

Insights into SARS-CoV-2 Persistence and Its Relevance

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