SARS-CoV-2 infection among Colorado adults working outside the home: Occupation, race and ethnicity and mask use.

OBJECTIVES: The workplace is an important setting for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure and transmission. Using data from a large case-control study in Colorado during 2021 and 2022, we aimed to evaluate working outside the home and SARS-CoV-2 infection, the racial and ethnic distribution of workers in occupations associated with infection, and workplace face mask use. METHODS: Cases were Colorado adults with a positive SARS-CoV-2 test by reverse transcription-polymerase chain reaction (RT-PCR) reported to Colorado's COVID-19 surveillance system selected from surveillance data ≤12 days after their specimen collection date. Control participants were randomly selected adult Coloradans with a RT-PCR-confirmed negative SARS-CoV-2 test result reported to the same surveillance system. RESULTS: Working outside the home was associated with infection (odds ratio [OR] = 1.46, 95% confidence interval [CI]: 1.39-1.54). Among participants working outside the home, "Food Preparation and Serving Related" (aOR = 2.35, 95% CI: 1.80-3.06), "Transportation and Material Moving" (aOR = 2.09, 95% CI: 1.62-2.69), "Construction and Extraction" (aOR = 1.88, 95% CI: 1.36-2.59), "Protective Service" (aOR = 1.60, 95% CI: 1.15-2.24), and "Sales and Related" (aOR = 1.44, 95% CI: 1.22-1.69) were occupational categories most strongly associated with infection. American Indian/Alaskan Native, Black, and Hispanic/Latino participants were more likely than others to work in occupational categories with the highest odds of infection (p < 0.05). Cases were less likely than controls to report always wearing a mask (31.9% vs. 41.5%) and wearing a KN95/N95/KF94 mask (16.8% vs. 27.2%) at work. CONCLUSIONS: These findings emphasize the importance of occupation and workplace mask use in the COVID-19 pandemic and its disproportionate racial/ethnic impact on workers.

Characteristics of People Who Do Not Complete a Public Health Interview: An Assessment of Colorado Enteric Disease Surveillance Data.

OBJECTIVES: Although enteric disease case interviews are critical for control measures and education, not all case-patients are interviewed. We evaluated systematic differences between people with an enteric disease in Colorado who were and were not interviewed to identify ways to increase response rates and reduce biases in the surveillance data used to guide public health interventions. METHODS: We obtained data from the Colorado Electronic Disease Reporting System from March 1, 2017, through December 31, 2019. Among case-patients not interviewed and interviewed, we used univariate analyses to describe sociodemographic characteristics, timing of contact attempts, and effect of additional funding. RESULTS: As compared with case-patients who were interviewed, case-patients who were not interviewed were significantly more likely to be aged 18 to 39 years (35.7% vs 31.7%; P < .001); identify as male, Hispanic, or Black; be experiencing homelessness or hospitalization; reside in rural/frontier areas or an institution; or live in areas with lower levels of education, life expectancy, and income. Time to first contact attempt was longer for case-patients who were not interviewed than for those who were (mean days from specimen collection to first contact attempt, 9.8 vs 6.8; P < .001). Residing in a jurisdiction with additional funding for interviewing was associated with increased interview rates (87.7% vs 68.8%) and timeliness of public health report and first contact attempt (2.3 vs 4.4 days; P < .001). CONCLUSION: Findings can guide efforts to improve response rates in groups least likely to be interviewed, resulting in reduced biases in surveillance data, better disease mitigation, and increased efficiency in case investigations. Timeliness of case interviews and additional funding to conduct case investigations were factors in increasing response rates.

Lessons Learned From a Sequential Mixed-Mode Survey Design to Recruit and Collect Data From Case-Control Study Participants: Formative Evaluation.

BACKGROUND: Sequential mixed-mode surveys using both web-based surveys and telephone interviews are increasingly being used in observational studies and have been shown to have many benefits; however, the application of this survey design has not been evaluated in the context of epidemiological case-control studies. OBJECTIVE: In this paper, we discuss the challenges, benefits, and limitations of using a sequential mixed-mode survey design for a case-control study assessing risk factors during the COVID-19 pandemic. METHODS: Colorado adults testing positive for SARS-CoV-2 were randomly selected and matched to those with a negative SARS-CoV-2 test result from March to April 2021. Participants were first contacted by SMS text message to complete a self-administered web-based survey asking about community exposures and behaviors. Those who did not respond were contacted for a telephone interview. We evaluated the representativeness of survey participants to sample populations and compared sociodemographic characteristics, participant responses, and time and resource requirements by survey mode using descriptive statistics and logistic regression models. RESULTS: Of enrolled case and control participants, most were interviewed by telephone (308/537, 57.4% and 342/648, 52.8%, respectively), with overall enrollment more than doubling after interviewers called nonresponders. Participants identifying as female or White non-Hispanic, residing in urban areas, and not working outside the home were more likely to complete the web-based survey. Telephone participants were more likely than web-based participants to be aged 18-39 years or 60 years and older and reside in areas with lower levels of education, more linguistic isolation, lower income, and more people of color. While there were statistically significant sociodemographic differences noted between web-based and telephone case and control participants and their respective sample pools, participants were more similar to sample pools when web-based and telephone responses were combined. Web-based participants were less likely to report close contact with an individual with COVID-19 (odds ratio [OR] 0.70, 95% CI 0.53-0.94) but more likely to report community exposures, including visiting a grocery store or retail shop (OR 1.55, 95% CI 1.13-2.12), restaurant or cafe or coffee shop (OR 1.52, 95% CI 1.20-1.92), attending a gathering (OR 1.69, 95% CI 1.34-2.15), or sport or sporting event (OR 1.05, 95% CI 1.05-1.88). The web-based survey required an average of 0.03 (SD 0) person-hours per enrolled participant and US $920 in resources, whereas the telephone interview required an average of 5.11 person-hours per enrolled participant and US $70,000 in interviewer wages. CONCLUSIONS: While we still encountered control recruitment challenges noted in other observational studies, the sequential mixed-mode design was an efficient method for recruiting a more representative group of participants for a case-control study with limited impact on data quality and should be considered during public health emergencies when timely and accurate exposure information is needed to inform control measures.

Community exposures among Colorado adults who tested positive for SARS-CoV-2 -A case-control study, March-December 2021.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which causes coronavirus disease 2019 (COVID-19), is spread primarily through exposure to respiratory droplets from close contact with an infected person. To inform prevention measures, we conducted a case-control study among Colorado adults to assess the risk of SARS-CoV-2 infection from community exposures. METHODS: Cases were symptomatic Colorado adults (aged ≥18 years) with a positive SARS-CoV-2 test by reverse transcription-polymerase chain reaction (RT-PCR) reported to Colorado's COVID-19 surveillance system. From March 16 to December 23, 2021, cases were randomly selected from surveillance data ≤12 days after their specimen collection date. Cases were matched on age, zip code (urban areas) or region (rural/frontier areas), and specimen collection date with controls randomly selected among persons with a reported negative SARS-CoV-2 test result. Data on close contact and community exposures were obtained from surveillance and a survey administered online. RESULTS: The most common exposure locations among all cases and controls were place of employment, social events, or gatherings and the most frequently reported exposure relationship was co-worker or friend. Cases were more likely than controls to work outside the home (adjusted odds ratio (aOR) 1.18, 95% confidence interval (CI): 1.09-1.28) in industries and occupations related to accommodation and food services, retail sales, and construction. Cases were also more likely than controls to report contact with a non-household member with confirmed or suspected COVID-19 (aOR 1.16, 95% CI: 1.06-1.27). CONCLUSIONS: Understanding the settings and activities associated with a higher risk of SARS-CoV-2 infection is essential for informing prevention measures aimed at reducing the transmission of SARS-CoV-2 and other respiratory diseases. These findings emphasize the risk of community exposure to infected persons and the need for workplace precautions in preventing ongoing transmission.