Natural Ventilation and Air Purification for Effective Removal of Airborne Virus in Classrooms with Heater Operation.

Mass COVID-19 infection cases in indoor spaces have been continuously reported since its global outbreak, generating increasing public interest in reducing the spread of the virus. This study considered a situation in which an infected individual continuously releases the virus into the air in a classroom, simulated by continuous injection of NaCl particles ≤ 5 µm, with heater operation during winter. The effects of applying natural ventilation and operating one or two air purifiers on the removal of virus-containing aerosols were experimentally compared and analyzed based on the spatiotemporal changes in NaCl concentration within the classroom. When a heater was operated with all windows shut, operating one and two air purifiers reduced the amount of the aerosol in indoor air by approximately 50 and 60%, respectively, compared to the case with no air purifier. Additionally, when the heater was operated with one or two air purifiers under natural ventilation, the amount of virus-containing aerosol in the air was reduced by 86-88% compared to the case with neither natural ventilation nor air purifier. Because natural ventilation significantly varies with weather conditions and particulate matter concentrations, combining natural ventilation with air purifiers in classrooms during winter needs to be adjusted appropriately.

Relationship between Preventive Health Behavior, Optimistic Bias, Hypochondria, and Mass Psychology in Relation to the Coronavirus Pandemic among Young Adults in Korea.

The great challenge to global public health caused by the coronavirus pandemic has lasted for two years in Korea. However, Korean young adults seem less compliant with preventive health behaviors than older adults. This study aims to explore the relationship between risk perception variables of optimistic bias, hypochondriasis, and mass psychology, and preventive health behavior in relation to the coronavirus pandemic through a cross-sectional online survey. The participants are 91 Korean young adults aged 19-30. The results show that mass psychology has a positive relationship with preventive health behavior, whereas optimistic bias and hypochondriasis do not. In detail, people with high or middle levels of mass psychology displayed higher preventive health behavior compared with those who had low levels of mass psychology, and the highest compliance was for wearing a mask, followed by COVID-19 vaccination, whereas the lowest compliance was for influenza vaccination. These findings could be explained by the Korean culture of strong collectivism and the characteristics of COVID-19, which evoked extreme fear globally. The results of this study can be useful for policy establishment in the ongoing prevention of COVID-19 and suggest that mass psychology should be used effectively in planning preventive communication campaigns.

The Changing Tides of Caregiving During the COVID-19 Pandemic: How Decreasing and Increasing Care Provision Relates to Caregiver Well-Being.

OBJECTIVES: Pandemic-specific changes to the caregiving context (e.g., attempts to reduce exposure, physical distancing requirements) may lead to changes in care provision. This study uses the 2020 National Health and Aging Trends Study Family Members and Friends coronavirus disease 2019 (COVID-19) questionnaire to explore changes in the amount of care provision during COVID-19 and associations with stress process outcomes of caregiving. METHODS: The sample includes 1,020 caregivers who provided care for an older adult during COVID-19. Caregivers indicated whether their hours of care decreased, stayed stable, or increased during the pandemic. We describe reasons for change in care and compare changes in care by demographic and care-related characteristics using chi-squares and analyses of variance, and relate changes in care with stress process outcomes (e.g., overload, COVID-related anxiety) using multivariable linear regression. RESULTS: Caregivers were 60.7 years old on average, 69.3% were female, and 18.6% were non-White. While most caregivers reported no change, 30.5% reported an increase and 11.5% reported a decrease in the amount of pandemic care provided. Relative to maintaining stable care provision, an increase was associated broadly with worse mental health and care-related stress, whereas a decrease was associated with greater emotional difficulty related to care and lower levels of positive affectivity. DISCUSSION: Those who changed their care provision during the pandemic predominantly did so to protect their care recipient from COVID-19 exposure. Increasing one's care provision was strongly associated with worse mental health and well-being. Supports for caregivers who take on additional care tasks during the pandemic could have great public health benefit.

Older Adults’ Worry about COVID-19: Associations with Experiences of COVID-19 Among Social Connections

The COVID-19 pandemic has challenged the physical and mental health of older adults, yet it is unknown how much older adults worry about their own exposure. As older adults are at increased risk for severe complications from COVID-19, understanding patterns of worry may inform public health guidelines and interventions for this age group. We investigated older adults’ worry about COVID-19 in the early months of the pandemic and associations with familial/friend’s diagnosis or disease symptoms. Data comes from the baseline (April/May 2020), one-month, and two-month follow-up surveys from the COVID-19 Coping Study, a national longitudinal cohort study of US adults aged ≥55. We used linear regression models to investigate the association between self-reported familial/friend diagnosis or symptoms with pandemic worry, accounting for demographic factors and individual diagnosis or experience of COVID-19 symptoms. Participants (Baseline=4379, 1 month= 2553, 2 month=2682) were 67 years old on average, 72% were female, 5.7% were non-White, and 80.5% had a college degree. At baseline, 26.6% of participants had friends or family who had been diagnosed or experienced symptoms of COVID-19. Having friends or family diagnosed or with symptoms of COVID-19 (B=0.08, SE=0.04, p<.05), being female (B=0.42, SE=0.03, p<.001), and having higher educational attainment (B=0.06, SE=0.02, p<.001) were significantly associated with greater worry about COVID-19. These associations were consistent over 3 months. Understanding if worry about the pandemic correlates with following public health guidelines is a key next step so intervention strategies can prioritize older adults and their social networks.

Potential implications of SARS-CoV-2 oral infection in the host microbiota.

The oral cavity, as the entry point to the body, may play a critical role in the pathogenesis of SARS-CoV-2 infection that has caused a global outbreak of the coronavirus disease 2019 (COVID-19). Available data indicate that the oral cavity may be an active site of infection and an important reservoir of SARS-CoV-2. Considering that the oral surfaces are colonized by a diverse microbial community, it is likely that viruses have interactions with the host microbiota. Patients infected by SARS-CoV-2 may have alterations in the oral and gut microbiota, while oral species have been found in the lung of COVID-19 patients. Furthermore, interactions between the oral, lung, and gut microbiomes appear to occur dynamically whereby a dysbiotic oral microbial community could influence respiratory and gastrointestinal diseases. However, it is unclear whether SARS-CoV-2 infection can alter the local homeostasis of the resident microbiota, actively cause dysbiosis, or influence cross-body sites interactions. Here, we provide a conceptual framework on the potential impact of SARS-CoV-2 oral infection on the local and distant microbiomes across the respiratory and gastrointestinal tracts ('oral-tract axes'), which remains largely unexplored. Studies in this area could further elucidate the pathogenic mechanism of SARS-CoV-2 and the course of infection as well as the clinical symptoms of COVID-19 across different sites in the human host.

Affordable oral health care: dental biofilm disruption using chloroplast made enzymes with chewing gum delivery.

Current approaches for oral health care rely on procedures that are unaffordable to impoverished populations, whereas aerosolized droplets in the dental clinic and poor oral hygiene may contribute to spread of several infectious diseases including COVID-19, requiring new solutions for dental biofilm/plaque treatment at home. Plant cells have been used to produce monoclonal antibodies or antimicrobial peptides for topical applications to decrease colonization of pathogenic microbes on dental surface. Therefore, we investigated an affordable method for dental biofilm disruption by expressing lipase, dextranase or mutanase in plant cells via the chloroplast genome. Antibiotic resistance gene used to engineer foreign genes into the chloroplast genome were subsequently removed using direct repeats flanking the aadA gene and enzymes were successfully expressed in marker-free lettuce transplastomic lines. Equivalent enzyme units of plant-derived lipase performed better than purified commercial enzymes against biofilms, specifically targeting fungal hyphae formation. Combination of lipase with dextranase and mutanase suppressed biofilm development by degrading the biofilm matrix, with concomitant reduction of bacterial and fungal accumulation. In chewing gum tablets formulated with freeze-dried plant cells, expressed protein was stable up to 3 years at ambient temperature and was efficiently released in a time-dependent manner using a mechanical chewing simulator device. Development of edible plant cells expressing enzymes eliminates the need for purification and cold-chain transportation, providing a potential translatable therapeutic approach. Biofilm disruption through plant enzymes and chewing gum-based delivery offers an effective and affordable dental biofilm control at home particularly for populations with minimal oral care access.

Femtomolar SARS-CoV-2 Antigen Detection Using the Microbubbling Digital Assay with Smartphone Readout Enables Antigen Burden Quantitation and Tracking.

BACKGROUND: High-sensitivity severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen assays are desirable to mitigate false negative results. Limited data are available to quantify and track SARS-CoV-2 antigen burden in respiratory samples from different populations. METHODS: We developed the Microbubbling SARS-CoV-2 Antigen Assay (MSAA) with smartphone readout, with a limit of detection of 0.5 pg/mL (10.6 fmol/L) nucleocapsid antigen or 4000 copies/mL inactivated SARS-CoV-2 virus in nasopharyngeal (NP) swabs. We developed a computer vision and machine learning-based automatic microbubble image classifier to accurately identify positives and negatives and quantified and tracked antigen dynamics in intensive care unit coronavirus disease 2019 (COVID-19) inpatients and immunocompromised COVID-19 patients. RESULTS: Compared to qualitative reverse transcription-polymerase chain reaction methods, the MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) and a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study with 372 residual clinical NP swabs. In immunocompetent individuals, the antigen positivity rate in swabs decreased as days-after-symptom-onset increased, despite persistent nucleic acid positivity. Antigen was detected for longer and variable periods of time in immunocompromised patients with hematologic malignancies. Total microbubble volume, a quantitative marker of antigen burden, correlated inversely with cycle threshold values and days-after-symptom-onset. Viral sequence variations were detected in patients with long duration of high antigen burden. CONCLUSIONS: The MSAA enables sensitive and specific detection of acute infections and quantification and tracking of antigen burden and may serve as a screening method in longitudinal studies to identify patients who are likely experiencing active rounds of ongoing replication and warrant close viral sequence monitoring.