Association Between COVID-19 Exposure and Self-reported Compliance With Public Health Guidelines Among Essential Employees at an Institution of Higher Education in the US.

Importance: Detailed analysis of infection rates paired with behavioral and employee-reported risk factors is vital to understanding how transmission of SARS-CoV-2 infection may be exacerbated or mitigated in the workplace. Institutions of higher education are heterogeneous work units that supported continued in-person employment during the COVID-19 pandemic, providing a test site for occupational health evaluation. Objective: To evaluate the association between self-reported protective behaviors and prevalence of SARS-CoV-2 infection among essential in-person employees during the first 6 months of the COVID-19 pandemic in the US. Design, Setting, and Participants: This cross-sectional study was conducted from July 13 to September 2, 2020, at an institution of higher education in Fort Collins, Colorado. Employees 18 years or older without symptoms of COVID-19 who identified as essential in-person workers during the first 6 months of the pandemic were included. Participants completed a survey, and blood and nasal swab samples were collected to assess active SARS-CoV-2 infection via quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and past infection by serologic testing. Exposure: Self-reported practice of protective behaviors against COVID-19 according to public health guidelines provided to employees. Main Outcomes and Measures: Prevalence of current SARS-CoV-2 infection detected by qRT-PCR or previous SARS-CoV-2 infection detected by an IgG SARS-CoV-2 testing platform. The frequency of protective behavior practices and essential workers' concerns regarding contracting COVID-19 and exposing others were measured based on survey responses. Results: Among 508 participants (305 [60.0%] women, 451 [88.8%] non-Hispanic White individuals; mean [SD] age, 41.1 [12.5] years), there were no qRT-PCR positive test results, and only 2 participants (0.4%) had seroreactive IgG antibodies. Handwashing and mask wearing were reported frequently both at work (480 [94.7%] and 496 [97.8%] participants, respectively) and outside work (465 [91.5%] and 481 [94.7%] participants, respectively). Social distancing was reported less frequently at work (403 [79.5%]) than outside work (465 [91.5%]) (P < .001). Participants were more highly motivated to avoid exposures because of concern about spreading the infection to others (419 [83.0%]) than for personal protection (319 [63.2%]) (P < .001). Conclusions and Relevance: In this cross-sectional study of essential workers at an institution of higher education, when employees reported compliance with public health practices both at and outside work, they were able to operate safely in their work environment during the COVID-19 pandemic.

Comparison of dengue virus type 2-specific small RNAs from RNA interference-competent and -incompetent mosquito cells.

The exogenous RNA interference (RNAi) pathway is an important antiviral defense against arboviruses in mosquitoes, and virus-specific small interfering (si)RNAs are key components of this pathway. Understanding the biogenesis of siRNAs in mosquitoes could have important ramifications in using RNAi to control arbovirus transmission. Using deep sequencing technology, we characterized dengue virus type 2 (DENV2)-specific small RNAs produced during infection of Aedes aegypti mosquitoes and A. aegypti Aag2 cell cultures and compared them to those produced in the C6/36 Aedes albopictus cell line. We show that the size and mixed polarity of virus-specific small RNAs from DENV-infected A. aegypti cells indicate that they are products of Dicer-2 (Dcr2) cleavage of long dsRNA, whereas C6/36 cells generate DENV2-specific small RNAs that are longer and predominantly positive polarity, suggesting that they originate from a different small RNA pathway. Examination of virus-specific small RNAs after infection of the two mosquito cell lines with the insect-only flavivirus cell fusing agent virus (CFAV) corroborated these findings. An in vitro assay also showed that Aag2 A. aegypti cells are capable of siRNA production, while C6/36 A. albopictus cells exhibit inefficient Dcr2 cleavage of long dsRNA. Defective expression or function of Dcr2, the key initiator of the RNAi pathway, might explain the comparatively robust growth of arthropod-borne viruses in the C6/36 cell line, which has been used frequently as a surrogate for studying molecular interactions between arboviruses and cells of their mosquito hosts.