Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity

Guallar, María Pilar; Meiriño, R.; Donat‐Vargas, Carolina; Corral, Octavio; Jouvé, Nicolás; Soriano, Vincent

doi:10.1016/j.ijid.2020.06.035

Cited by 108 publications

(112 citation statements)

References 11 publications

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“…First, a very high dose of virus might have led to the second instance of infection and induced more severe disease. 23 Second, it is possible that reinfection was caused by a version of the virus that was more virulent, or more virulent in this patient's context. Third, a mechanism of antibody-dependent enhancement might be the cause, a means by which specific Fc-bearing immune cells become infected with virus by binding to specific antibodies.…”

Section: Discussionmentioning

confidence: 99%

Genomic evidence for reinfection with SARS-CoV-2: a case study

Tillett

Sevinsky²,

Hartley

et al. 2021

The Lancet Infectious Diseases

729

741

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Background The degree of protective immunity conferred by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently unknown. As such, the possibility of reinfection with SARS-CoV-2 is not well understood. We describe an investigation of two instances of SARS-CoV-2 infection in the same individual.Methods A 25-year-old man who was a resident of Washoe County in the US state of Nevada presented to health authorities on two occasions with symptoms of viral infection, once at a community testing event in April, 2020, and a second time to primary care then hospital at the end of May and beginning of June, 2020. Nasopharyngeal swabs were obtained from the patient at each presentation and twice during follow-up. Nucleic acid amplification testing was done to confirm SARS-CoV-2 infection. We did next-generation sequencing of SARS-CoV-2 extracted from nasopharyngeal swabs. Sequence data were assessed by two different bioinformatic methodologies. A short tandem repeat marker was used for fragment analysis to confirm that samples from both infections came from the same individual.Findings The patient had two positive tests for SARS-CoV-2, the first on April 18, 2020, and the second on June 5, 2020, separated by two negative tests done during follow-up in May, 2020. Genomic analysis of SARS-CoV-2 showed genetically significant differences between each variant associated with each instance of infection. The second infection was symptomatically more severe than the first.Interpretation Genetic discordance of the two SARS-CoV-2 specimens was greater than could be accounted for by short-term in vivo evolution. These findings suggest that the patient was infected by SARS-CoV-2 on two separate occasions by a genetically distinct virus. Thus, previous exposure to SARS-CoV-2 might not guarantee total immunity in all cases. All individuals, whether previously diagnosed with COVID-19 or not, should take identical precautions to avoid infection with SARS-CoV-2. The implications of reinfections could be relevant for vaccine development and application.

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Section: Discussionmentioning

confidence: 99%

Genomic evidence for reinfection with SARS-CoV-2: a case study

Tillett

Sevinsky²,

Hartley

et al. 2021

The Lancet Infectious Diseases

729

741

View full text Add to dashboard Cite

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“…Despite that difficulty, emerging evidence consistent with a dose-response relationship between the infecting dose and disease severity has been recently observed in three clusters of individuals that were exposed to diverse inocula and developed divergent clinical forms of COVID-19 disease. [27] The potential infecting doses were determined by the extent of physical distancing and precautionary measures that the individuals followed. It was evident that in the clusters which did not follow physical distancing or other precautions, such as wearing masks, a larger proportion of individuals developed severe disease, whereas only asymptomatic or mild disease was seen in the cluster, where exposure had been low.…”

Section: Emerging Evidence From Sars-cov-2/covid-19mentioning

confidence: 99%

“…It was evident that in the clusters which did not follow physical distancing or other precautions, such as wearing masks, a larger proportion of individuals developed severe disease, whereas only asymptomatic or mild disease was seen in the cluster, where exposure had been low. [27] …”

Section: Emerging Evidence From Sars-cov-2/covid-19mentioning

confidence: 99%

“… Clusters of severe cases and clusters of mild cases. [27] Primary cases with severe disease result in transmitting higher doses of infectious inocula, while those with mild disease transmit lower doses. Health care workers with a low-risk profile got severe COVID-19, infected from very sick patients, e.g.…”

Section: The Inoculum Theory Provides a Logical Explanation For Severmentioning

confidence: 99%

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COVID-19: Does the infectious inoculum dose-response relationship contribute to understanding heterogeneity in disease severity and transmission dynamics?

Damme

Dahake²,

Pas

et al. 2021

Medical Hypotheses

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“…The association between viral load and clinical outcome including severity of symptoms is still poorly characterized although the majority of studies reported an association between higher viral loads and more severe symptoms [11][12][13][14][15][16][17][18][19].…”

Section: Association Of Viral Load With Symptoms and Outcomementioning

confidence: 99%

Potential sources, modes of transmission and effectiveness of prevention measures against SARS-CoV-2

Kampf

Brüggemann

Kaba

et al. 2020

Journal of Hospital Infection

131

121

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Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity

Cited by 108 publications

References 11 publications

Genomic evidence for reinfection with SARS-CoV-2: a case study

Genomic evidence for reinfection with SARS-CoV-2: a case study

COVID-19: Does the infectious inoculum dose-response relationship contribute to understanding heterogeneity in disease severity and transmission dynamics?

Potential sources, modes of transmission and effectiveness of prevention measures against SARS-CoV-2

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