Outdoor Transmission of SARS-CoV-2 and Other Respiratory Viruses: A Systematic Review

Bulfone, Tommaso C.; Malekinejad, Mohsen; Rutherford, George W; Razani, Nooshin

doi:10.1093/infdis/jiaa742

Cited by 323 publications

(281 citation statements)

References 34 publications

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“…Individuals working outside and in the fields were more likely to be both currently infected and seropositive, respectively. Whereas indoor exposures are thought to be associated with the greatest risk of transmission, 19 a lower perceived sense of risk during outdoor work, difficulty using PPE while engaged in physically demanding tasks, or socioeconomic differences among outdoor and indoor workers may contribute to the observed association in our study. While the estimated risk ratio for infection associated with workplace exposure was lower than that for household exposure, this difference could in part reflect misclassification, if individuals are are more likely to know about the health of household members.…”

Section: Discussionmentioning

confidence: 65%

Risk factors for SARS-CoV-2 infection among farmworkers in Monterey County, California

Mora

Lewnard

Kogut

et al. 2021

Preprint

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Importance: Essential workers in agriculture and food production have been severely affected by the ongoing COVID-19 pandemic. Objective: To identify risk factors associated with SARS-CoV-2 shedding and antibody response in farmworkers in California. Design: This cross-sectional study collected survey data and determined current SARS-CoV-2 shedding and seropositivity among 1,107 farmworkers in California's Salinas Valley from 16 July to 30 November 2020. Setting: Farmworkers receiving transcription-mediated amplification (TMA) tests for SARS-CoV-2 infection at federally qualified community clinics and community sites were invited to participate in our study. Participants: Individuals were eligible if they were not pregnant, were 18 years old or older, had conducted farm work since the pandemic started, and were proficient in English or Spanish. Exposures: Sociodemographic, household, community, and workplace characteristics. Main Outcome(s) and Measure(s): Current (as indicated by TMA positivity) and historical (as indicated by IgG seropositivity) SARS-CoV-2 infection. Results: Most farmworkers enrolled in the study were born in Mexico, had primary school or lower levels of educational attainment, and were overweight or obese. Current SARS-CoV-2 shedding was associated in multivariable analyses with attained only primary or lower educational levels (RR=1.32; 95% CI: 0.99-1.76), speaking an indigenous language at home (RR=1.30; 0.97-1.73), working in the fields (RR=1.60; 1.03-2.50), and exposure to known or suspected COVID-19 case at home (RR=2.98; 2.06-4.32) or in the workplace (RR=1.59; 1.18-2.14). Antibody detection was associated with residential exposures including living in crowded housing (RR=1.23; 0.98-1.53), with children (RR=1.40; 1.1-1.76) or unrelated roommates (RR=1.40; 1.19-1.64), and with a known or suspected COVID-19 case (RR=1.59; 1.13-2.24). Those who were obese (RR=1.65; 1.01-2.70) or diabetic (RR=1.31; 0.98-1.75) were also more likely to be seropositive. Farmworkers who lived in rural areas other than Greenfield (RR=0.58; 0.47-0.71), worked indoors (RR=0.68; 0.61-0.77), or whose employer provided them with information on how to protect themselves at work (RR=0.59; 0.40-0.86) had lower risk of prior infection.

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Section: Discussionmentioning

confidence: 65%

Risk factors for SARS-CoV-2 infection among farmworkers in Monterey County, California

Mora

Lewnard

Kogut

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…According to Dabisch et al, temperature, simulated sunlight, and humidity are among significant factors affecting the infectious SARS-CoV-2 durability in aerosols (Dabisch et al, 2020). Additionally, in enclosed spaces, low humidity, air conditioning, and low UV light may cause viral aerosol to survive longer (Bulfone et al, 2020). Results from this study indicated that the main transmission route for COVID-19 was person to person contact (Zhang et al, 2020).…”

Section: Discussionmentioning

confidence: 65%

Ventilation Systems and COVID-19 Spread: Evidence from a Systematic Review Study

Fadaei

2021

EUR J SUSTAIN DEV RES

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The main transmission mechanism of COVID-19 is through close contact, aerosols, droplets, and fomites transmission of the disease in closed spaces. In this study, the importance of ventilation in preventing the expansion of COVID-19 is reviewed. In total, 20 articles are reviewed. The obtained results show that ventilation has a crucial role in preventing COVID-19 expansion in indoor air environments. However, it should be used properly; otherwise, it will cause further expansion of the disease, as suggested for SARS. Appropriate ventilation can effectively prevent the expansion of COVID-19, and it will be more effective if be combined with particle filtration and air disinfection. The benefit of ventilation in highly polluted outdoor air conditions is an important field to be investigated in future studies. Finally, the results show that the six basic COVID-19 control strategies include: hand hygiene, social distancing, screening and case finding, isolation and separating, decontamination and disinfection, and effective ventilation. We hope that the results of the present study help researchers and health decision-makers in designing programs further perceive the importance of factors related to indoor conditions to control COVID-19 expansion.

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“…35 Outdoor proximity is thought to have a much lower risk of transmission than indoor proximity, with studies reporting a 19 times greater risk of transmission indoors compared to outdoors. 36…”

Section: Discussionmentioning

confidence: 99%

Evaluating the impacts of tiered restrictions introduced in England, during October and December 2020 on COVID-19 cases: A synthetic control study

Zhang

Owen

Green

et al. 2021

Preprint

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Background In 2020, a second wave of COVID-19 cases unevenly affected places in England leading to the introduction of a tiered system of controls with different geographical areas subject to different levels of restrictions. Whilst previous research has examined the impact of national lockdowns on transmission, there has been limited research examining the marginal effect of differences in localised restrictions or how these effects vary between socioeconomic contexts. We therefore examined how Tier 3 restrictions in England implemented between October-December 2020, which included additional restrictions on the hospitality sector and people meeting outdoors affected COVID-19 case rates, compared to Tier 2 restrictions, and how these effects varied by level of deprivation. Methods We used data on weekly reported COVID-19 cases for 7201 neighbourhoods in England and adjusted these for changing case-detection rates to provide an estimate of weekly SARS-CoV-2 infections in each neighbourhood. We identified those areas that entered Tier 3 restrictions at two time points in October and December, and constructed a synthetic control group of similar places that had entered Tier 2 restrictions, using calibration weights to match them on a wide range of covariates that may influence transmission. We then compared the change in weekly infections between those entering Tier 3 to the synthetic control group to estimate the proportional reduction of cases resulting from Tier 3 restrictions compared to Tier 2 restrictions, over a 4-week period. We further used interaction analysis to estimate whether this effect differed based on the level of socioeconomic deprivation in each neighbourhood and whether effects were modified by the prevalence of a new more infectious variant of SARS-CoV-2 (B.1.1.7) in each area. Results The introduction of Tier 3 restrictions in October and December was associated with a 14% (95% CI 10% to 19%) and 20% (95% CI 13% to 29%) reduction in infections respectively, compared to the rates expected if only Tier 2 restrictions had been in place in those areas. We found that effects were similar across levels of deprivation and limited evidence that Tier 3 restrictions had a greater effect in areas where the new more infectious variant was more prevalent. Interpretation Additional restrictions on hospitality and meeting outdoors introduced in Tier 3 areas in England had a moderate effect on transmission and these restrictions did not appear to increase inequalities, having a similar impact across areas with differing levels of socioeconomic deprivation. Where transmission risks vary between geographical areas a tiered approach of local restrictions on outdoor mixing and hospitality can contribute to control of SARS-CoV-2 and is unlikely to increases inequalities in transmission.

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Outdoor Transmission of SARS-CoV-2 and Other Respiratory Viruses: A Systematic Review

Cited by 323 publications

References 34 publications

Risk factors for SARS-CoV-2 infection among farmworkers in Monterey County, California

Risk factors for SARS-CoV-2 infection among farmworkers in Monterey County, California

Ventilation Systems and COVID-19 Spread: Evidence from a Systematic Review Study

Evaluating the impacts of tiered restrictions introduced in England, during October and December 2020 on COVID-19 cases: A synthetic control study

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