Exhaled SARS-CoV-2 RNA viral load kinetics measured by facemask sampling associates with household transmission

Pan, Daniel; Williams, Caroline; Decker, Jonathan; Fletcher, Eve; Sze, Shirley; Assadi, Sara; Haigh, Richard D.; Saleem, Baber; Nazareth, Joshua; Garton, Natalie J.; Pareek, Manish; Barer, Michael R.

doi:10.1016/j.cmi.2022.07.005

Cited by 11 publications

(9 citation statements)

References 24 publications

(30 reference statements)

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“…Despite these limitations, the study results were consistent with those of other studies that showed that the mask viral load could indicate transmission risk, 30 the Delta variant had a propensity for higher transmission, 4,25 and vaccination helps in reducing transmission, 11 suggesting that the mask sampling approach can be used for understanding the transmission risk of SARS-CoV-2.…”

Section: Discussionsupporting

confidence: 87%

“…27 Although direct relation to the actual transmission was not established in this study, a correlation of emission quantity from similar mask sampling to transmission has been shown for other airborne diseases 28,29 and very recently for SARS-CoV-2. 30 The UK study showed that for every log increase in peak exhaled SARS-CoV-2 RNA by the index case, the probability of household transmission increased by 5-20-fold. A similar analysis of our dataset with the same definition for household transmission showed three-fold more household transmission in our high emitter group.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of COVID‐19 vaccination on transmission risk of breakthrough infections: Lessons from adapted N95 mask sampling for emerging variants and interventions

Sriraman

Shaikh

Vaswani

et al. 2022

Journal of Medical Virology

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This study used an adapted N95 mask sampling to understand the effect of COVID‐19 vaccination in the context of circulating variants on infected individuals to emit the virus into the air, a key risk factor of transmission. Mask, swab, and blood samples were collected from 92 COVID‐19 patients vaccinated (Covishield/COVAXIN‐partial/fully) or unvaccinated between July and September 2021 during the Delta‐dominated period in Mumbai. Mask/swab samples were analysed by RT‐PCR for viral RNA. Blood was evaluated for SARS‐CoV‐2 anti‐spike and nucleocapsid antibody responses. At < 48 hours of diagnosis, 93% of the patients emitted detectable viral RNA, with 40% emitting >1000 copies in 30‐minutes (high emitters). About 8% continued to be high emitters even after eight days of symptom onset. No significant difference was observed in emission patterns between partial, full and un‐vaccinated patients. However, when vaccinated patients were stratified based on spike protein neutralisation and nucleocapsid IgG, the group with moderate/high neutralisation showed a significantly lower proportion of high emitters and viral RNA copies than the group with no/low neutralisation, which further reduced in the group having anti‐nucleocapsid IgG. In conclusion, mask sampling showed that Delta infections were associated with greater virus emission in patients, which was significantly reduced only in vaccinated patients with moderate/high SARS‐CoV2 neutralisation, especially with evidence of past infection. The study demonstrated that mask sampling could be useful for understanding the transmission risk of emerging variants, screening vaccine/booster candidates and guiding control interventions. This article is protected by copyright. All rights reserved.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Impact of COVID‐19 vaccination on transmission risk of breakthrough infections: Lessons from adapted N95 mask sampling for emerging variants and interventions

Sriraman

Shaikh

Vaswani

et al. 2022

Journal of Medical Virology

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“…Indeed, mask sampling of infected individuals in the community has shown a better correlation with transmission within households than viral loads detected in URT swabs. 9 Future human infection challenge studies that include emission monitoring might offer a means for testing the efficacy of agents and vaccines aimed at blocking transmission.…”

Section: Discussionmentioning

confidence: 99%

“… 4 , 5 , 6 , 7 Indeed, recent data have shown the more transmissible omicron variant is more readily detected in airborne particles despite lower viral titres in nasal swabs than previous variants, and another study directly linked emissions collected in masks to household transmission. 8 , 9 …”

Section: Introductionmentioning

confidence: 99%

Viral emissions into the air and environment after SARS-CoV-2 human challenge: a phase 1, open label, first-in-human study

et al. 2023

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“…Chen et al [44] found that LRT viral load was a much more accurate prognostic indicator for COVID-19 severity than URT viral load (up to 81% accuracy for LRT vs 65% for URT). Pan et al [175] also found that those who had a positive facemask sample but negative URT sample had significantly higher median symptom scores than those who were facemask negative but URT positive (15 vs 3, p = 0.0017). Since aerosols produced during breathing originate from the LRT, LRT infection is a requirement for the production of infectious breath aerosols (see Section 4.1).…”

Section: Biological Evidencementioning

confidence: 98%

Symptom propagation in respiratory pathogens of public health concern: a review of the evidence

Asplin,

Mancy,

Finnie

et al. 2024

Preprint

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Symptom propagation occurs when the symptom set an individual experiences is correlated with the symptom set of the individual who infected them. Symptom propagation may dramatically affect epidemiological outcomes, potentially causing clusters of severe disease. Conversely, it could result in chains of mild infection, generating widespread immunity with minimal cost to public health.Despite accumulating evidence that symptom propagation occurs for many respiratory pathogens, the underlying mechanisms are not well understood. Here we conducted a scoping literature review for 14 respiratory pathogens to ascertain the extent of evidence for symptom propagation by two mechanisms: dose-severity relationships and route-severity relationships.We identify considerable heterogeneity between pathogens in the relative importance of the two mechanisms, highlighting the importance of pathogen-specific investigations. For almost all pathogens, including influenza and SARS-CoV-2, we found support for at least one of the two mechanisms. For some pathogens, including influenza, we found convincing evidence that both mechanisms contribute to symptom propagation.Furthermore, infectious disease models traditionally do not include symptom propagation. We summarise the present state of modelling advancements to address the methodological gap. We then investigate a simplified disease outbreak scenario, finding that under strong symptom propagation, quarantining mildly infected individuals can have negative epidemiological implications.

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Exhaled SARS-CoV-2 RNA viral load kinetics measured by facemask sampling associates with household transmission

Cited by 11 publications

References 24 publications

Impact of COVID‐19 vaccination on transmission risk of breakthrough infections: Lessons from adapted N95 mask sampling for emerging variants and interventions

Impact of COVID‐19 vaccination on transmission risk of breakthrough infections: Lessons from adapted N95 mask sampling for emerging variants and interventions

Viral emissions into the air and environment after SARS-CoV-2 human challenge: a phase 1, open label, first-in-human study

Symptom propagation in respiratory pathogens of public health concern: a review of the evidence

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