Which factors influence the extent of indoor transmission of SARS-CoV-2? A rapid evidence review

Goodwin, Lara; Hayward, Toneka; Krishan, Prerna; Nolan, Gemma; Nundy, Madhurima; Ostrishko, Kayla; Attili, Antonio; Cárceles, Salva Barranco; Epelle, Emmanuel I.; Gabl, Roman; Pappa, E. J.; Stajuda, Mateusz; Zen, Simone; Dozier, Marshall; Anderson, Niall; Viola, Ignazio Maria; McQuillan, Ruth

doi:10.7189/jogh.11.10002

Cited by 20 publications

(17 citation statements)

References 78 publications

(99 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…People after infection may become carriers of the coronavirus and can infect others not only by excreting the coronavirus from the mouth, nose, but also stool [17][18][19][20][21][22]. History provides us with much evidence of the importance of fecal disposal and disinfection during epidemics.…”

Section: Discussionmentioning

confidence: 99%

A way to eliminate the novel coronavirus and stop the COVID-19 epidemics: A new idea

Zajac¹

2022

GSC Biol. and Pharm. Sci.

View full text Add to dashboard Cite

To the question: why there is so much novel coronavirus in wastewater worldwide is the general answer that it is because the body gets rid of the virus. Thus, as the virus leaves the body, the body cleanses and gradually gets rid of the virus. That would be a logical statement, but it is not true. Based on our results so far, part of the virus leaves the body, but the body does not get rid of it. The virus can settle in the intestinal tract and can remain in its carrier there for a very long time, even years. The presence of the virus in the intestinal tract can be confirmed by RT PCR for a new coronavirus from rectal swabs

show abstract

Section: Discussionmentioning

confidence: 99%

A way to eliminate the novel coronavirus and stop the COVID-19 epidemics: A new idea

Zajac¹

2022

GSC Biol. and Pharm. Sci.

View full text Add to dashboard Cite

show abstract

“…It is well established that SARS-CoV-2 is readily transmitted in indoor environments (11)(12)(13). Airborne transmission has being recognized as an important route of transmission (14,15).…”

Section: Discussionmentioning

confidence: 99%

The role of airborne transmission in a large single source outbreak of SARS-CoV-2 in a Belgian nursing home in 2020

Vuylsteke

Cuypers

Baele

et al. 2021

Preprint

View full text Add to dashboard Cite

Objectives: To better understand the conditions which have led to one of the largest COVID-19 outbreaks in Belgian nursing homes in 2020. Setting: A nursing home in Flanders, Belgium, which experienced a massive outbreak of COVID-19 after a cultural event. An external volunteer who dressed as a legendary figure visited consecutively the 4 living units and tested positive for SARS-CoV-2 the next day. Within days, residents started to display symptoms and the outbreak spread rapidly within the nursing home. Methods: We interviewed key informants and collected standardized data from all residents retrospectively. A batch of 115 positive samples with a Ct value of <37 by qRT-PCR were analysed using whole-genome sequencing. Six months after the outbreak, ventilation assessment of gathering rooms in the nursing home was done using a tracer gas test with calibrated CO2 sensors. Results: Timeline of diagnoses and symptom onsets clearly pointed to the cultural event as the start of the outbreak, with the volunteer as index case. The genotyping of positive samples depicted the presence of one large cluster, suggesting a single source outbreak. The global attack rate among residents was 77% with a significant association between infection and presence at the event. Known risk factors such as short distance to or physical contact with the volunteer, and wearing of a mask during the event were not associated with early infection. The ventilation assessment showed a high background average CO2 level in four main rooms varying from 657 ppm to 846 ppm. Conclusions: Our investigation shows a rapid and widespread single source outbreak of SARS-CoV-2 in a nursing home, in which airborne transmission was the most plausible explanation for the massive intra-facility spread. Our results underscore the importance of ventilation and air quality for the prevention of future outbreaks in closed facilities.

show abstract

“…3 The meta-analytic estimates of the SARs were extracted from the 7 meta-analyses meeting the inclusion criteria. [13][14][15][16][17][18][19] All analyses were conducted in R. 20 The NNE model makes four assumptions. First, we assume the Delta variant correction factor (𝐶𝐹 𝐷𝑒𝑙𝑡𝑎 =1.97) is accurate.…”

Section: Methodsmentioning

confidence: 99%

Evaluating the number of unvaccinated people needed to exclude to prevent SARS-CoV-2 transmissions

Prosser

Helfer

Streiner

2021

Preprint

View full text Add to dashboard Cite

BackgroundVaccine mandates and vaccine passports (VMVP) for SARS-CoV-2 are thought to be a path out of the pandemic by increasing vaccination through coercion and excluding unvaccinated people from different settings because they are viewed as being at significant risk of transmitting SARS-CoV-2. While variants and waning efficacy are relevant, SARS-CoV-2 vaccines reduce the risk of infection, transmission, and severe illness/hospitalization in adults. Thus, higher vaccination levels are beneficial by reducing healthcare system pressures and societal fear. However, the benefits of excluding unvaccinated people are unknown.MethodsA method to evaluate the benefits of excluding unvaccinated people to reduce transmissions is described, called the number needed to exclude (NNE). The NNE is analogous to the number needed to treat (NNT=1/ARR), except the absolute risk reduction (ARR) is the baseline transmission risk in the population for a setting (e.g., healthcare). The rationale for the NNE is that exclusion removes all unvaccinated people from a setting, such that the ARR is the baseline transmission risk for that type of setting, which depends on the secondary attack rate (SAR) typically observed in that type of setting and the baseline infection risk in the population. The NNE is the number of unvaccinated people who need to be excluded from a setting to prevent one transmission event from unvaccinated people in that type of setting. The NNE accounts for the transmissibility of the currently dominant Delta (B.1.617.2) variant to estimate the minimum NNE in six types of settings: households, social gatherings, casual close contacts, work/study places, healthcare, and travel/transportation. The NNE can account for future potentially dominant variants (e.g., Omicron, B.1.1.529). To assist societies and policymakers in their decision-making about VMVP, the NNEs were calculated using the current (mid-to-end November 2021) baseline infection risk in many countries.FindingsThe NNEs suggest that at least 1,000 unvaccinated people likely need to be excluded to prevent one SARS-CoV-2 transmission event in most types of settings for many jurisdictions, notably Australia, California, Canada, China, France, Israel, and others. The NNEs of almost every jurisdiction examined are well within the range of the NNTs of acetylsalicylic acid (ASA) in primary prevention of cardiovascular disease (CVD) (≥ 250 to 333). This is important since ASA is not recommended for primary prevention of CVD because the harms outweigh the benefits. Similarly, the harms of exclusion may outweigh the benefits. These findings depend on the accuracy of the model assumptions and the baseline infection risk estimates.ConclusionsVaccines are beneficial, but the high NNEs suggest that excluding unvaccinated people has negligible benefits for reducing transmissions in many jurisdictions across the globe. This is because unvaccinated people are likely not at significant risk – in absolute terms – of transmitting SARS-CoV-2 to others in most types of settings since current baseline transmission risks are negligible. Consideration of the harms of exclusion is urgently needed, including staffing shortages from losing unvaccinated healthcare workers, unemployment/unemployability, financial hardship for unvaccinated people, and the creation of a class of citizens who are not allowed to fully participate in many areas of society.RegistrationCRD42021292263FundingThis study received no grant from any funding agency, commercial, or not-for-profit sectors. It has also received no support of any kind from any individual or organization. BH is supported by a personal research grant from the University of Wroclaw within the “Excellence Initiative – Research University” framework and by a scholarship from the Polish Ministry of Education and Science. None of these institutions were involved in this research and did not fund it directly.Competing interestsThe authors have no competing interests to declare.Ethical approvalNot applicable. All the work herein was performed using publicly available data.Data reportingThe data used in this work are available at https://tinyurl.com/4m8mm4jh and https://decision-support-tools.com/.

show abstract

Which factors influence the extent of indoor transmission of SARS-CoV-2? A rapid evidence review

Cited by 20 publications

References 78 publications

A way to eliminate the novel coronavirus and stop the COVID-19 epidemics: A new idea

A way to eliminate the novel coronavirus and stop the COVID-19 epidemics: A new idea

The role of airborne transmission in a large single source outbreak of SARS-CoV-2 in a Belgian nursing home in 2020

Evaluating the number of unvaccinated people needed to exclude to prevent SARS-CoV-2 transmissions

Contact Info

Product

Resources

About