Validation of a novel sampling technology for airborne allergens in low-income urban homes

Measuring SARS-CoV-2 aerosolization in rooms of hospitalized patients

Objective

Airborne spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a significant risk for healthcare workers. Understanding transmission of SARS-CoV-2 in the hospital could help minimize nosocomial infection. The objective of this pilot study was to measure aerosolization of SARS-CoV-2 in the hospital rooms of COVID-19 patients.

Methods

Two air samplers (Inspirotec) were placed 1 and 4 m away from adults with SARS-CoV-2 infection hospitalized at an urban, academic tertiary care center from June to October 2020. Airborne SARS-CoV-2 concentration was measured by quantitative reverse transcription polymerase chain reaction and analyzed by clinical parameters and patient demographics.

Results

Thirteen patients with COVID-19 (eight females [61.5%], median age: 57 years old, range 25-82) presented with shortness of breath (100%), cough (38.5%) and fever (15.4%). Respiratory therapy during air sampling varied: mechanical ventilation via endotracheal tube (n = 3), high flow nasal cannula (n = 4), nasal cannula (n = 4), respiratory helmet (n = 1), and room air (n = 1). SARS-CoV-2 RNA was identified in rooms of three out of three intubated patients compared with one out of 10 of the non-intubated patients (p = .014). Airborne SARS-CoV-2 tended to decrease with distance (1 vs. 4 m) in rooms of intubated patients.

Conclusions

Hospital rooms of intubated patients had higher levels of aerosolized SARS-CoV-2, consistent with increased aerosolization of virus in patients with severe disease or treatment with positive pressure ventilation through an endotracheal tube. While preliminary, these data have safety implications for health care workers and design of protective measures in the hospital.

Level of Evidence

2.

Assessment of a Program for SARS-CoV-2 Screening and Environmental Monitoring in an Urban Public School District

IMPORTANCE

Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings.

OBJECTIVES

To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning.

DESIGN, SETTING, AND PARTICIPANTS

This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to evaluate surrogacy for case detection and interrogate transmission risk of in-building activities.

MAIN OUTCOMES AND MEASURES

SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection.

RESULTS

A total of 2885 supervised, self-collected saliva samples were tested from 458 asymptomatic staff members (mean [SD] age, 42.9 [12.4] years; 303 women [66.2%]; 25 Black or African American [5.5%], 83 Hispanic [18.1%], 312 White [68.1%], and 35 other or not provided [7.6%]) and 315 students (mean age, 14.2 [0.7] years; 151 female students [48%]; 20 Black or African American [6.3%], 201 Hispanic [63.8%], 75 White [23.8%], and 19 other race or not provided [6.0%]). A total of 46 cases of SARS-CoV-2 (22 students and 24 staff members) were detected, representing an increase in cumulative case detection rates from 1.2% (12 of 1000) to 7.0% (70 of 1000) among students and from 2.1% (21 of 1000) to 5.3% (53 of 1000) among staff compared with conventional reporting mechanisms during the pilot period. SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools as well as in air samples collected from 2 choir rooms. Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with 1 school. Geographical analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools.

CONCLUSIONS AND RELEVANCE

In this study of staff and students in 3 urban public schools in Omaha, Nebraska, weekly screening of asymptomatic staff and students by saliva polymerase chain reaction testing was associated with increased SARS-CoV-2 case detection, exceeding infection rates reported at the county level. Experiences differed among schools, and virus sequencing and geographical analyses suggested a dynamic interplay of school-based and community-derived transmission risk. Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the kindergarten through 12th grade educational setting.

Assessment of a Program for SARS-CoV-2 Screening and Environmental Monitoring in an Urban Public School District

Importance

Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings.

Objectives

To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning.

Design, Setting, and Participants

This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to evaluate surrogacy for case detection and interrogate transmission risk of in-building activities.

Main Outcomes and Measures

SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection.

Results

A total of 2885 supervised, self-collected saliva samples were tested from 458 asymptomatic staff members (mean [SD] age, 42.9 [12.4] years; 303 women [66.2%]; 25 Black or African American [5.5%], 83 Hispanic [18.1%], 312 White [68.1%], and 35 other or not provided [7.6%]) and 315 students (mean age, 14.2 [0.7] years; 151 female students [48%]; 20 Black or African American [6.3%], 201 Hispanic [63.8%], 75 White [23.8%], and 19 other race or not provided [6.0%]). A total of 46 cases of SARS-CoV-2 (22 students and 24 staff members) were detected, representing an increase in cumulative case detection rates from 1.2% (12 of 1000) to 7.0% (70 of 1000) among students and from 2.1% (21 of 1000) to 5.3% (53 of 1000) among staff compared with conventional reporting mechanisms during the pilot period. SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools as well as in air samples collected from 2 choir rooms. Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with 1 school. Geographical analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools.

Conclusions and Relevance

In this study of staff and students in 3 urban public schools in Omaha, Nebraska, weekly screening of asymptomatic staff and students by saliva polymerase chain reaction testing was associated with increased SARS-CoV-2 case detection, exceeding infection rates reported at the county level. Experiences differed among schools, and virus sequencing and geographical analyses suggested a dynamic interplay of school-based and community-derived transmission risk. Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the kindergarten through 12th grade educational setting.

Assessment of a Program for SARS-CoV-2 Screening and Environmental Monitoring in an Urban Public School District

IMPORTANCE

Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings.

OBJECTIVES

To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning.

DESIGN, SETTING, AND PARTICIPANTS

This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to evaluate surrogacy for case detection and interrogate transmission risk of in-building activities.

MAIN OUTCOMES AND MEASURES

SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection.

RESULTS

A total of 2885 supervised, self-collected saliva samples were tested from 458 asymptomatic staff members (mean [SD] age, 42.9 [12.4] years; 303 women [66.2%]; 25 Black or African American [5.5%], 83 Hispanic [18.1%], 312 White [68.1%], and 35 other or not provided [7.6%]) and 315 students (mean age, 14.2 [0.7] years; 151 female students [48%]; 20 Black or African American [6.3%], 201 Hispanic [63.8%], 75 White [23.8%], and 19 other race or not provided [6.0%]). A total of 46 cases of SARS-CoV-2 (22 students and 24 staff members) were detected, representing an increase in cumulative case detection rates from 1.2% (12 of 1000) to 7.0% (70 of 1000) among students and from 2.1% (21 of 1000) to 5.3% (53 of 1000) among staff compared with conventional reporting mechanisms during the pilot period. SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools as well as in air samples collected from 2 choir rooms. Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with 1 school. Geographical analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools.

CONCLUSIONS AND RELEVANCE

In this study of staff and students in 3 urban public schools in Omaha, Nebraska, weekly screening of asymptomatic staff and students by saliva polymerase chain reaction testing was associated with increased SARS-CoV-2 case detection, exceeding infection rates reported at the county level. Experiences differed among schools, and virus sequencing and geographical analyses suggested a dynamic interplay of school-based and community-derived transmission risk. Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the kindergarten through 12th grade educational setting.

Sampling Devices for Indoor Allergen Exposure: Pros and Cons

PURPOSE OF REVIEW

To review current indoor allergen sampling devices, including devices to measure allergen in reservoir and airborne dust, and personal sampling devices, with attention to sampling rationale and major indoor allergen size and characteristics.

RECENT FINDINGS

While reservoir dust vacuuming samples and airborne dust volumetric air sampling remain popular techniques, recent literature describes sampling using furnace filters and ion-charging devices, both which help to eliminate the need for trained staff; however, variable correlation with reservoir dust and volumetric air sampling has been described. Personal sampling devices include intra-nasal samples and personal volumetric air samples. While these devices may offer better estimates of breathable allergens, they are worn for short periods of time and can be cumbersome. Reservoir dust sampling is inexpensive and is possible for families to perform. Airborne dust sampling can be more expensive and may better quantify cat, dog, and mouse allergen exposure. Personal sampling devices may offer a better representation of breathable air.

Bedroom Allergen Exposure Beyond House Dust Mites

PURPOSE OF REVIEW

The review provides insight into recent findings on bedroom allergen exposures, primarily focusing on pet, pest, and fungal exposures.

RECENT FINDINGS

Large-scale studies and improved exposure assessment technologies, including measurement of airborne allergens and of multiple allergens simultaneously, have extended our understanding of indoor allergen exposures and their impact on allergic disease. Practical, streamlined methods for exposure reduction have shown promise in some settings, and potential protective effects of early-life exposures have been further elucidated through the investigation of specific bacterial taxa. Advances in molecular allergology have yielded novel data on sensitization profiles and cross-reactivity. The role of indoor allergen exposures in allergic disease is complex and remains incompletely understood. Advancing our knowledge of various co-exposures, including the environmental and host microbiome, that interact with allergens in early life will be crucial for the development of efficacious interventions to reduce the substantial economic and social burden of allergic diseases including asthma.

Bedroom exposure to airborne allergens in the Chicago area using a patient-operated sampling device

BACKGROUND

In current practice, allergens in vacuum-collected dust are used as surrogates for inhalable allergens. We developed an air-sampling device that can be used by patients for direct measurement of airborne allergen concentrations in their own homes.

OBJECTIVE

To demonstrate the use of this device to establish allergen concentration reference ranges in a target population and to evaluate associations between patient-reported information and measured allergen concentrations.

METHODS

Patients from 5 allergist's practices in the Chicagoland region were provided with instructions, questionnaires, informed consent forms, and samplers to run for 5 days in their bedrooms. Samples were collected from cartridges and assayed by multiplex immunoassays for 12 common household allergens and enzyme-linked immunosorbent assay for ragweed.

RESULTS

Unique allergen profiles were obtained for 102 patient homes. Samples with allergen concentrations above the limit of detection were as follows: total dust mite, 28%; cat, 61%; dog, 64%; mouse, 12%; rat, 0%; cockroach, 4%; Alternaria, 6%; Aspergillus, 21%; birch pollen 1%; grass, 8%; and ragweed, 5%. Of those, 75 completed questionnaires, providing meta-data for further analysis. Pet allergens correlated significantly with number of pets owned. Humidity correlated with dust mite allergens, open windows with Alternaria and mouse allergens, and high-efficiency particulate air filter use with reduced levels of several allergens. Many other variables showed no significant correlations.

CONCLUSION

The combination of ease of use, high air-sampling rate, and sensitive immunoassays permitted the measurement of airborne allergen concentrations in homes and establishment of reference ranges. Patient-reported information permitted identification of factors that could relate to allergen concentrations and suggested remedial measures.