Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer

Symptom propagation in respiratory pathogens of public health concern: a review of the evidence

Symptom propagation occurs when the symptom set an individual experiences is correlated with the symptom set of the individual who infected them. Symptom propagation may dramatically affect epidemiological outcomes, potentially causing clusters of severe disease. Conversely, it could result in chains of mild infection, generating widespread immunity with minimal cost to public health. Despite accumulating evidence that symptom propagation occurs for many respiratory pathogens, the underlying mechanisms are not well understood. Here, we conducted a scoping literature review for 14 respiratory pathogens to ascertain the extent of evidence for symptom propagation by two mechanisms: dose-severity relationships and route-severity relationships. We identify considerable heterogeneity between pathogens in the relative importance of the two mechanisms, highlighting the importance of pathogen-specific investigations. For almost all pathogens, including influenza and SARS-CoV-2, we found support for at least one of the two mechanisms. For some pathogens, including influenza, we found convincing evidence that both mechanisms contribute to symptom propagation. Furthermore, infectious disease models traditionally do not include symptom propagation. We summarize the present state of modelling advancements to address the methodological gap. We then investigate a simplified disease outbreak scenario, finding that under strong symptom propagation, isolating mildly infected individuals can have negative epidemiological implications.

Please wear a mask: a systematic case for mask wearing mandates

This paper combines considerations from ethics, medicine and public health policy to articulate and defend a systematic case for mask wearing mandates (MWM). The paper argues for two main claims of general interest in favour of MWM. First, MWM provide a more effective, just and fair way to tackle the ongoing COVID-19 pandemic than policy alternatives such as laissez-faire approaches, mask wearing recommendations and physical distancing measures. And second, the proffered objections against MWM may justify some exemptions for specific categories of individuals, but do not cast doubt on the justifiability of these mandates. Hence, unless some novel decisive objections are put forward against MWM, governments should adopt MWM.

Evaluating the spike in the symptomatic proportion of SARS-CoV-2 in China in 2022 with variolation effects: a modeling analysis

Despite most COVID-19 infections being asymptomatic, mainland China had a high increase in symptomatic cases at the end of 2022. In this study, we examine China's sudden COVID-19 symptomatic surge using a conceptual SIR-based model. Our model considers the epidemiological characteristics of SARS-CoV-2, particularly variolation, from non-pharmaceutical intervention (facial masking and social distance), demography, and disease mortality in mainland China. The increase in symptomatic proportions in China may be attributable to (1) higher sensitivity and vulnerability during winter and (2) enhanced viral inhalation due to spikes in SARS-CoV-2 infections (high transmissibility). These two reasons could explain China's high symptomatic proportion of COVID-19 in December 2022. Our study, therefore, can serve as a decision-support tool to enhance SARS-CoV-2 prevention and control efforts. Thus, we highlight that facemask-induced variolation could potentially reduces transmissibility rather than severity in infected individuals. However, further investigation is required to understand the variolation effect on disease severity.

Epidemiological and health economic implications of symptom propagation in respiratory pathogens: A mathematical modelling investigation

BACKGROUND

Respiratory pathogens inflict a substantial burden on public health and the economy. Although the severity of symptoms caused by these pathogens can vary from asymptomatic to fatal, the factors that determine symptom severity are not fully understood. Correlations in symptoms between infector-infectee pairs, for which evidence is accumulating, can generate large-scale clusters of severe infections that could be devastating to those most at risk, whilst also conceivably leading to chains of mild or asymptomatic infections that generate widespread immunity with minimal cost to public health. Although this effect could be harnessed to amplify the impact of interventions that reduce symptom severity, the mechanistic representation of symptom propagation within mathematical and health economic modelling of respiratory diseases is understudied.

METHODS AND FINDINGS

We propose a novel framework for incorporating different levels of symptom propagation into models of infectious disease transmission via a single parameter, α. Varying α tunes the model from having no symptom propagation (α = 0, as typically assumed) to one where symptoms always propagate (α = 1). For parameters corresponding to three respiratory pathogens-seasonal influenza, pandemic influenza and SARS-CoV-2-we explored how symptom propagation impacted the relative epidemiological and health-economic performance of three interventions, conceptualised as vaccines with different actions: symptom-attenuating (labelled SA), infection-blocking (IB) and infection-blocking admitting only mild breakthrough infections (IB_MB). In the absence of interventions, with fixed underlying epidemiological parameters, stronger symptom propagation increased the proportion of cases that were severe. For SA and IB_MB, interventions were more effective at reducing prevalence (all infections and severe cases) for higher strengths of symptom propagation. For IB, symptom propagation had no impact on effectiveness, and for seasonal influenza this intervention type was more effective than SA at reducing severe infections for all strengths of symptom propagation. For pandemic influenza and SARS-CoV-2, at low intervention uptake, SA was more effective than IB for all levels of symptom propagation; for high uptake, SA only became more effective under strong symptom propagation. Health economic assessments found that, for SA-type interventions, the amount one could spend on control whilst maintaining a cost-effective intervention (termed threshold unit intervention cost) was very sensitive to the strength of symptom propagation.

CONCLUSIONS

Overall, the preferred intervention type depended on the combination of the strength of symptom propagation and uptake. Given the importance of determining robust public health responses, we highlight the need to gather further data on symptom propagation, with our modelling framework acting as a template for future analysis.

How much natural ventilation rate can suppress COVID-19 transmission in occupancy zones?

Background

Previous research has emphasized the importance of efficient ventilation in suppressing COVID-19 transmission in indoor spaces, yet suitable ventilation rates have not been suggested.

Materials and Methods

This study investigated the impacts of mechanical, natural, single-sided, cross-ventilation, and three mask types (homemade, surgical, N95) on COVID-19 spread across eight common indoor settings. Viral exposure was quantified using a mass balance calculation of inhaled viral particles, accounting for initial viral load, removal via ventilation, and mask filtration efficiency.

Results

Results demonstrated that natural cross-ventilation significantly reduced viral load, decreasing from 10,000 to 0 viruses over 15 minutes in a 100 m2 space by providing ~1325 m3/h of outdoor air via two 0.6 m2 openings at 1.5 m/s wind speed. In contrast, single-sided ventilation only halved viral load at best.

Conclusion

Natural cross-ventilation with masks effectively suppressed airborne viruses, lowering potential infections and disease transmission. The study recommends suitable ventilation rates to reduce COVID-19 infection risks in indoor spaces.

Mask Adherence and the Relationship Between Masking and Weather-Related Metrics

Little is known about adherence to COVID-19 masking mandates on college campuses or the relationship between weather-related variables and masking. This study aimed to (1) observe students' adherence to on-campus mask mandates and (2) estimate the effect of weather on mask-wearing. Temple University partnered in the Centers for Disease Control and Prevention's observational Mask Adherence Surveillance at Colleges and Universities Project. February-April 2021, weekly observations were completed at 12 on-campus locations to capture whether individuals wore masks, wore them correctly, and the type of mask worn. Fashion and university masks also were recorded. Weekly average temperature, humidity, and precipitation were calculated. Descriptive statistics were calculated for masking adherence overall, over time, and by location. Statistical significance was assessed between correct mask use and mask type and the linear relationships between weekly weather metrics and mask use. Overall, 3508 individuals were observed with 89.6% wearing masks. Of those, 89.4% correctly wore masks. Cloth (58.7%) and surgical masks (35.3%) were most commonly observed and 21.3% wore fashion masks. N95/KN95 masks were correctly worn in 98.3% of observations and surgical and cloth masks were correctly worn ~ 90% of the time. Weekly adherence varied over time and by campus location. Significant inverse linear relationships existed between weekly temperature (r = - 0.72; p < 0.05) and humidity (r = - 0.63; p ≤ 0.05) and masking. Mask adherence and correct use was high. Temperature and humidity inversely affected adherence. Adherence varied by on-campus location, which suggests the locations (e.g., academic buildings, recreational center) and possibly the characteristics of individuals who frequent certain areas impacted adherence.

Risk preferences, preventive behaviour, and the probability of a loss: Empirical evidence from the COVID-19 pandemic

RATIONALE

A theoretical model of optimal choice under risk, in which an individual chooses the level of prevention to avoid a loss, has the ambiguous prediction that a higher risk-taking preference increases the probability of a loss.

OBJECTIVE

To empirically investigate the prediction in the case of COVID-19 with individual-level survey data.

DATA

Survey data from the Understanding America Study (UAS). The UAS Coronavirus Tracking Survey followed 8628 respondents from March 2020 until July 2021 (29 survey waves) and data was gathered on having contracted COVID-19, vaccination, and preventive behaviour. Separate UAS modules gathered data on individuals' risk preferences; twice before and once during the COVID-19 pandemic. UAS also gathered data on pre-pandemic health and socio-economic status. Combining these data, and dropping missing observations, provided longitudinal data for 4335 respondents (96,370 observations) of whom 530 contracted COVID-19.

RESULTS

In support of the theoretical prediction, the empirical findings show that a one-standard deviation higher risk-taking preference is associated with about a one-third higher probability of contracting COVID-19 within two weeks. Furthermore, the findings show that individuals' risk-taking preference is negatively associated with the preventive behaviour of social distancing and not associated with getting vaccinated. There is, however, no support for preventive behaviour being associated with the probability of contracting COVID-19. The exception is for being vaccinated, which is negatively associated with the probability of contracting COVID-19. The findings, therefore, do not support that the positive association of the risk-taking preference with the probability of contracting COVID-19 is mediated through observed preventive behaviour.

CONCLUSIONS

The findings support the importance of individuals' risk-taking behaviour for contracting COVID-19 and, more generally, the importance of loss prevention as a risk management tool for individuals.

Children's moral reasoning about self- versus other-benefiting public health measures

The COVID-19 pandemic has introduced novel public health measures such as masking and social distancing. In adults, framing these behaviors as benefiting others versus the self has been shown to affect people's perceptions of public health measures and willingness to comply. Here we asked whether self- versus other-oriented frames of novel public health measures influence children's endorsement and moral reasoning. Children aged 5 to 10 years viewed hypothetical dilemmas of aliens in which we manipulated the frame (other-oriented or self-oriented) of the prevention behavior and the severity (high or low) of the potential harm. Across two studies (Study 1: N = 48; Study 2: N = 61), results showed that across ages framing the behaviors as other-oriented, but not self-oriented, yielded more positive ratings of individuals who followed the public health measures and more negative ratings of those who did not. Across both frames, children generally endorsed these public health measures when the severity was high. Children used more moralizing concepts in other-oriented frames and were more critical of intentional transgressions over accidental transgressions, demonstrating further evidence that other-oriented frames induce moral reasoning. We discuss the theoretical and practical implications of these framing effects for sociomoral reasoning and action.

Prevalence of Respiratory Infections during the 2018-2020 Period in the Paediatric Population of Primary Care Centres in Central Catalonia

Following the COVID-19 pandemic, policies such as social distancing, hand washing, and the use of masks were implemented, which could play an important role in the reduction of infectious diseases. An observational, descriptive, cross-sectional study was conducted to observe the prevalence of respiratory infections in children under 15 years of age during the 2018-2020 period in Primary Care centres in Central Catalonia. In 2020, there was a 44.3% decrease in total consultations for respiratory infections compared to 2019. All respiratory infections exhibited a significant decrease except flu-like syndrome; children between the ages of 6 and 12 had the highest prevalence of flu-like syndrome (87.6%), and the SARS-CoV-2-19 infection was most frequent (4%) among those between the ages of 12 and 15. Compared to urban centres, rural centres presented a higher prevalence of all infections except flu-like syndrome and SARS-CoV-2. In conclusion, the COVID-19 pandemic caused a significant decrease in the number of consultations for respiratory infections in the paediatric population, except for flu-like syndrome, which increased in cases in January, February, and March 2020. No differences were found between sexes, although differences were found in the distribution of the different age groups.

The Impact of Mask Mandates on Face Mask Use During the COVID-19 Pandemic: Longitudinal Survey Study

BACKGROUND

Face mask use has been associated with declines in COVID-19 incidence rates worldwide. A handful of studies have examined the factors associated with face mask use in North America during the COVID-19 pandemic; however, much less is known about the patterns of face mask use and the impact of mask mandates during this time. This information could have important policy implications, now and in the event of future pandemics.

OBJECTIVE

To address existing knowledge gaps, we assessed face mask usage patterns among British Columbia COVID-19 Population Mixing Patterns (BC-Mix) survey respondents and evaluated the impact of the provincial mask mandate on these usage patterns.

METHODS

Between September 2020 and July 2022, adult British Columbia residents completed the web-based BC-Mix survey, answering questions on the circumstances surrounding face mask use or lack thereof, movement patterns, and COVID-19-related beliefs. Trends in face mask use over time were assessed, and associated factors were evaluated using multivariable logistic regression. A stratified analysis was done to examine effect modification by the provincial mask mandate.

RESULTS

Of the 44,301 respondents, 81.9% reported wearing face masks during the 23-month period. In-store and public transit mask mandates supported monthly face mask usage rates of approximately 80%, which was further bolstered up to 92% with the introduction of the provincial mask mandate. Face mask users mostly visited retail locations (51.8%) and travelled alone by car (49.6%), whereas nonusers mostly traveled by car with others (35.2%) to their destinations-most commonly parks (45.7%). Nonusers of face masks were much more likely to be male than female, especially in retail locations and restaurants, bars, and cafés. In a multivariable logistic regression model adjusted for possible confounders, factors associated with face mask use included age, ethnicity, health region, mode of travel, destination, and time period. The odds of face mask use were 3.68 times greater when the provincial mask mandate was in effect than when it was not (adjusted odds ratio [aOR] 3.68, 95% CI 3.33-4.05). The impact of the mask mandate was greatest in restaurants, bars, or cafés (mandate: aOR 7.35, 95% CI 4.23-12.78 vs no mandate: aOR 2.81, 95% CI 1.50-5.26) and in retail locations (mandate: aOR 19.94, 95% CI 14.86-26.77 vs no mandate: aOR 7.71, 95% CI 5.68-10.46).

CONCLUSIONS

Study findings provide added insight into the dynamics of face mask use during the COVID-19 pandemic. Mask mandates supported increased and sustained high face mask usage rates during the first 2 years of the pandemic, having the greatest impact in indoor public locations with limited opportunity for physical distancing targeted by these mandates. These findings highlight the utility of mask mandates in supporting high face mask usage rates during the COVID-19 pandemic.

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

The clinical course and outcome of COVID-19 are highly variable, ranging from asymptomatic infections to severe disease and death. Understanding the risk factors of severe COVID-19 is relevant both in the clinical setting and at the epidemiological level. Here, we provide an overview of host, viral and environmental factors that have been shown or (in some cases) hypothesized to be associated with severe clinical outcomes. The factors considered in detail include the age and frailty, genetic polymorphisms, biological sex (and pregnancy), co- and superinfections, non-communicable comorbidities, immunological history, microbiota, and lifestyle of the patient; viral genetic variation and infecting dose; socioeconomic factors; and air pollution. For each category, we compile (sometimes conflicting) evidence for the association of the factor with COVID-19 outcomes (including the strength of the effect) and outline possible action mechanisms. We also discuss the complex interactions between the various risk factors.

Modelling of the Innate and Adaptive Immune Response to SARS Viral Infection, Cytokine Storm and Vaccination

In this work, we develop mathematical models of the immune response to respiratory viral infection, taking into account some particular properties of the SARS-CoV infections, cytokine storm and vaccination. Each model consists of a system of ordinary differential equations that describe the interactions of the virus, epithelial cells, immune cells, cytokines, and antibodies. Conventional analysis of the existence and stability of stationary points is completed by numerical simulations in order to study the dynamics of solutions. The behavior of the solutions is characterized by large peaks of virus concentration specific to acute respiratory viral infections. At the first stage, we study the innate immune response based on the protective properties of interferon secreted by virus-infected cells. Viral infection down-regulates interferon production. This competition can lead to the bistability of the system with different regimes of infection progression with high or low intensity. After that, we introduce the adaptive immune response with antigen-specific T- and B-lymphocytes. The resulting model shows how the incubation period and the maximal viral load depend on the initial viral load and the parameters of the immune response. In particular, an increase in the initial viral load leads to a shorter incubation period and higher maximal viral load. The model shows that a deficient production of antibodies leads to an increase in the incubation period and even higher maximum viral loads. In order to study the emergence and dynamics of cytokine storm, we consider proinflammatory cytokines produced by cells of the innate immune response. Depending on the parameters of the model, the system can remain in the normal inflammatory state specific for viral infections or, due to positive feedback between inflammation and immune cells, pass to cytokine storm characterized by the excessive production of proinflammatory cytokines. Finally, we study the production of antibodies due to vaccination. We determine the dose-response dependence and the optimal interval of vaccine dose. Assumptions of the model and obtained results correspond to the experimental and clinical data.

Change and Continuity in Preventive Practices Across the COVID-19 Pandemic Among Rural and Urban Latinx Immigrant Worker Families

BACKGROUND

(1)The COVID-19 pandemic has put essential workers at high risk for contracting the disease. This study documents situational compliance with public health recommendations such as masking and social distancing among rural and urban Latinx families, with the goal of understanding change over time in COVID-19 risk reduction behaviors.

METHODS

(2)Respondents for 67 rural families and 44 urban families responded to repeated telephone surveys at three time points in the first year of the pandemic, providing data on use of masks and social distancing by themselves and family members while interacting with others at home, work, and in the community. Cumulative logistic regression models were employed to compare changes in risk behaviors between rural and urban groups over time.

RESULTS

(3)While group descriptive results indicated behaviors that posed low risk at each time point, regression models revealed greater change between time points for rural than urban residents. Rural residents also had gendered patterns.

CONCLUSIONS

(4)Patterns of change appear to reflect structural issues such as seasonal labor demand and gender roles more than pandemic fatigue or changing public health recommendations. The findings suggest that structural factors play a role in individuals complying with public health prevention measures for COVID-19.

The significant value of sustainable cosmetics fragrance in the spotlight after COVID-19

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has brought major changes to the world's population. This has led to increased wearing of masks to prevent infectious diseases, which can contribute to exacerbation of stress and the emergence of mental illness due to a physical health crisis.

OBJECTIVES

Therefore, this study comprehensively investigated the reasons why cosmetics customers pay attention to sustainable fragrances after COVID-19.

METHODS

This review article is a literature review, and a narrative review approach was used in this study. A total of 598 references were selected from 2004 to 2022 using representative journal search sites such as PubMed, Google Scholar, Scopus, and RISS. Among them, a total of 39 articles were successfully completed in this study using the PRISMA flowchart in the final stage.

RESULTS

In this study, by identifying the changes and needs of K-beauty and global cosmetics industry consumers who aspire for sustainable safety amid the COVID-19 pandemic, the increase in bad breath caused by the increase in mask wearing was recognized, and the need for fragrance due to mental health was recognized. Demand is expected to increase.

CONCLUSION

This study tried to change the perception of cosmetic fragrances into safe edible fragrances. Therefore, it is expected to be used as an important marketing material for the global cosmetics market.

The Difference in Electromyographic Activity While Wearing a Medical Mask in Women with and without Temporomandibular Disorders

Wearing a medical mask influences resting activity of the temporalis anterior and masseter muscles in healthy young women. However, no studies link medical mask-wearing with masticatory muscle activity in patients with temporomandibular disorders (TMDs). Therefore, this study aims to compare electromyographic patterns while wearing a medical mask between women with and without temporomandibular disorders. Based on the Research Diagnostic Criteria for Temporomandibular Disorders, 115 adult women qualified for the study. Participants were divided into the following two groups: diagnosed TMDs (n = 55; mean age: 23.5 ± 2.3 years) and healthy women (n = 60; mean age: 23.7 ± 2.6 years). Examinations of the resting and functional electromyographic activity of the temporalis anterior (TA), superficial masseter (MM), anterior bellies of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) were carried out using the BioEMG III™. Both groups showed statistically significant decreases in resting masticatory muscle activity during medical mask examination compared to no mask measurement. The significant differences in no mask measurement between both groups were noted regarding resting masticatory activity, clenching in the intercuspal position, and clenching on dental cotton rollers. During medical mask examination, women with TMDs showed differences in resting masticatory activity and clenching on dental cotton rollers compared to the healthy group. In all analyzed variables, both groups showed similar electromyographic patterns in the maximum mouth opening measurement during medical mask and no mask examination. A medical mask influences the resting bioelectric activity of the masticatory muscles in women with temporomandibular disorders and healthy women. We observed differences and some similarities in resting and functional electromyographic patterns within masticatory and neck muscles in both groups during medical mask and no mask examination.

Antibacterial and Antiviral Effects of Ag, Cu and Zn Metals, Respective Nanoparticles and Filter Materials Thereof against Coronavirus SARS-CoV-2 and Influenza A Virus

Due to the high prevalence of infectious diseases and their concurrent outbreaks, there is a high interest in developing novel materials with antimicrobial properties. Antibacterial and antiviral properties of a range of metal-based nanoparticles (NPs) are a promising means to fight airborne diseases caused by viruses and bacteria. The aim of this study was to test antimicrobial metals and metal-based nanoparticles efficacy against three viruses, namely influenza A virus (H1N1; A/WSN/1933) and coronaviruses TGEV and SARS-CoV-2; and two bacteria, Escherichia coli and Staphylococcus aureus. The efficacy of ZnO, CuO, and Ag NPs and their respective metal salts, i.e., ZnSO₄, CuSO₄, and AgNO₃, was evaluated in suspensions, and the compounds with the highest antiviral efficacy were chosen for incorporation into fibers of cellulose acetate (CA), using electrospinning to produce filter materials for face masks. Among the tested compounds, CuSO₄ demonstrated the highest efficacy against influenza A virus and SARS-CoV-2 (1 h IC50 1.395 mg/L and 0.45 mg/L, respectively), followed by Zn salt and Ag salt. Therefore, Cu compounds were selected for incorporation into CA fibers to produce antiviral and antibacterial filter materials for face masks. CA fibers comprising CuSO₄ decreased SARS-CoV-2 titer by 0.38 logarithms and influenza A virus titer by 1.08 logarithms after 5 min of contact; after 1 h of contact, SARS-COV-2 virus was completely inactivated. Developed CuO- and CuSO₄-based filter materials also efficiently inactivated the bacteria Escherichia coli and Staphylococcus aureus. The metal NPs and respective metal salts were potent antibacterial and antiviral compounds that were successfully incorporated into the filter materials of face masks. New antibacterial and antiviral materials developed and characterized in this study are crucial in the context of the ongoing SARS-CoV-2 pandemic and beyond.

The Association Between Clinical Severity and Incubation Period of SARS-CoV-2 Delta Variants: Retrospective Observational Study

BACKGROUND

As of August 25, 2021, Jiangsu province experienced the largest COVID-19 outbreak in eastern China that was seeded by SARS-CoV-2 Delta variants. As one of the key epidemiological parameters characterizing the transmission dynamics of COVID-19, the incubation period plays an essential role in informing public health measures for epidemic control. The incubation period of COVID-19 could vary by different age, sex, disease severity, and study settings. However, the impacts of these factors on the incubation period of Delta variants remains uninvestigated.

OBJECTIVE

The objective of this study is to characterize the incubation period of the Delta variant using detailed contact tracing data. The effects of age, sex, and disease severity on the incubation period were investigated by multivariate regression analysis and subgroup analysis.

METHODS

We extracted contact tracing data of 353 laboratory-confirmed cases of SARS-CoV-2 Delta variants' infection in Jiangsu province, China, from July to August 2021. The distribution of incubation period of Delta variants was estimated by using likelihood-based approach with adjustment for interval-censored observations. The effects of age, sex, and disease severity on the incubation period were expiated by using multivariate logistic regression model with interval censoring.

RESULTS

The mean incubation period of the Delta variant was estimated at 6.64 days (95% credible interval: 6.27-7.00). We found that female cases and cases with severe symptoms had relatively longer mean incubation periods than male cases and those with nonsevere symptoms, respectively. One-day increase in the incubation period of Delta variants was associated with a weak decrease in the probability of having severe illness with an adjusted odds ratio of 0.88 (95% credible interval: 0.71-1.07).

CONCLUSIONS

In this study, the incubation period was found to vary across different levels of sex, age, and disease severity of COVID-19. These findings provide additional information on the incubation period of Delta variants and highlight the importance of continuing surveillance and monitoring of the epidemiological characteristics of emerging SARS-CoV-2 variants as they evolve.

The face behind the Covid-19 mask - A comprehensive review

The threat of epidemic outbreaks like SARS-CoV-2 is growing owing to the exponential growth of the global population and the continual increase in human mobility. Personal protection against viral infections was enforced using ambient air filters, face masks, and other respiratory protective equipment. Available facemasks feature considerable variation in efficacy, materials usage and characteristic properties. Despite their widespread use and importance, face masks pose major potential threats due to the uncontrolled manufacture and disposal techniques. Improper solid waste management enables viral propagation and increases the volume of associated biomedical waste at an alarming rate. Polymers used in single-use face masks include a spectrum of chemical constituents: plasticisers and flame retardants leading to health-related issues over time. Despite ample research in this field, the efficacy of personal protective equipment and its impact post-disposal is yet to be explored satisfactorily. The following review assimilates information on the different forms of personal protective equipment currently in use. Proper waste management techniques pertaining to such special wastes have also been discussed. The study features a holistic overview of innovations made in face masks and their corresponding impact on human health and environment. Strategies with SDG3 and SDG12, outlining safe and proper disposal of solid waste, have also been discussed. Furthermore, employing the CFD paradigm, a 3D model of a face mask was created based on fluid flow during breathing techniques. Lastly, the review concludes with possible future advancements and promising research avenues in personal protective equipment.

To mask or not to mask: Debunking the myths of mask-wearing during COVID-19 across cultures

Mask-wearing is the simplest yet most effective preventive behavior during COVID-19. However, it has sparked great controversy, particularly in America. Little is known about what psychosocial factors predict people’s decision to mask. This research challenges three myths about mask-wearing. First, does mask-wearing provide a false sense of security? Second, is knowledge of COVID-19 a more robust predictor than political ideology of mask-wearing behavior? Third, does resistance to masks reflect anti-authoritarianism or a lack of trust in government? With nationally representative samples across two cultures (N = 1,121), findings reveal a significant positive correlation between mask-wearing and other preventive behaviors. Moreover, knowledge of COVID-19 and trust in government significantly predicted mask-wearing. Implications of the results are also discussed in the cross-cultural context. Critically, findings could provide practical implications for public education and policymaking by uncovering how to more effectively promote compliance with recommended preventive behaviors during our ongoing struggle with COVID-19.

Modeling the change in European and US COVID-19 death rates

Motivated by several possible differences in Covid-19 virus strains, age demographics, and face mask wearing between continents and countries, we focussed on changes in Covid death rates in 2020. We have extended our Covid-19 multicompartment model (Khan et al., 2020) to fit cumulative case and death data for 49 European countries and 52 US states and territories during the recent pandemic, and found that the case mortality rate had decreased by at least 80% in most of the US and at least 90% in most of Europe. We found that death rate decreases do not have strong correlations to other model parameters (such as contact rate) or other standard state/national metrics such as population density, GDP, and median age. Almost all the decreases occurred between mid-April and mid-June 2020, which corresponds to the time when many state and national lockdowns were relaxed resulting in surges of new cases. We examine here several plausible causes for this drop—improvements in treatment, face mask wearing, new virus strains, testing, potentially changing demographics of infected patients, and changes in data collection and reporting—but none of their effects are as significant as the death rate changes suggest. In conclusion, this work shows that a two death rate model is effective in quantifying the reported drop in death rates.

Incubation period of coronavirus disease 2019: new implications for intervention and control

The COVID-19 pandemic has been causing serious disasters to mankind. The incubation period is a key parameter for epidemic control and also an important basis for epidemic prediction, but its distribution law remains unclear. This paper analyzed the epidemiological information of 787 confirmed non-Wuhan resident cases, and systematically studied the characteristics of the incubation period of COVID-19 based on the interval-censored data estimation method. The results show that the incubation period of COVID-19 approximately conforms to the Gamma distribution with a mean value of 7.8 (95%CI:7.4-8.5) days and a median value of 7.0 (95%CI:6.7-7.3) days. The incubation period was positively correlated with age and negatively correlated with disease severity. Female cases presented a slightly higher incubation period than that of males. The proportion of infected persons who developed symptoms within 14 days was 91.6%. These results are of great significance to the prevention and control of the COVID-19 pandemic.

Household factors and the risk of severe COVID-like illness early in the U.S. pandemic

OBJECTIVE

To investigate the role of children in the home and household crowding as risk factors for severe COVID-19 disease.

METHODS

We used interview data from 6,831 U.S. adults screened for the Communities, Households and SARS/CoV-2 Epidemiology (CHASING) COVID Cohort Study in April 2020.

RESULTS

In logistic regression models, the adjusted odds ratio [aOR] of hospitalization due to COVID-19 for having (versus not having) children in the home was 10.5 (95% CI:5.7-19.1) among study participants living in multi-unit dwellings and 2.2 (95% CI:1.2-6.5) among those living in single unit dwellings. Among participants living in multi-unit dwellings, the aOR for COVID-19 hospitalization among participants with more than 4 persons in their household (versus 1 person) was 2.5 (95% CI:1.0-6.1), and 0.8 (95% CI:0.15-4.1) among those living in single unit dwellings.

CONCLUSION

Early in the US SARS-CoV-2 pandemic, certain household exposures likely increased the risk of both SARS-CoV-2 acquisition and the risk of severe COVID-19 disease.

Safe reopening of university campuses is possible with COVID-19 vaccination

We construct an agent-based SEIR model to simulate COVID-19 spread at a 16000-student mostly non-residential urban university during the Fall 2021 Semester. We find that mRNA vaccine coverage at 100% combined with weekly screening testing of 25% of the campus population make it possible to safely reopen to in-person instruction. Our simulations exhibit a right-skew for total infections over the semester that becomes more pronounced with less vaccine coverage, less vaccine effectiveness and no additional preventative measures. This suggests that high levels of infection are not exceedingly rare with campus social connections the main transmission route. Finally, we find that if vaccine coverage is 100% and vaccine effectiveness is above 80%, then a safe reopening is possible even without facemask use. This models possible future scenarios with high coverage of additional "booster" doses of COVID-19 vaccines.

COVID-19 Infectious Disease Prevention and Mitigation Practices by Chiropractic Physicians and Licensed Massage Therapists in Mississippi: A Needs Assessment to Inform Health Education and Promotion

Objective

The purpose of this study was to assess self-reported infection prevention processes and their effect on businesses of chiropractic doctors (DCs) and licensed massage therapists (LMTs) in Mississippi during the COVID-19 pandemic.

Methods

We developed a survey that was electronically delivered to all licensed DCs and LMTs in Mississippi between August and September 2020. Assessments were made using Qualtrics software, with data management and subsequent analysis including Pearson's χ² test.

Results

Responses were based on 32 of 323 DCs and 69 of 934 LMTs that were still seeing patients through the pandemic (n = 101, response rate 8%). The DC and LMT practitioners (94%) used treatment table and/or surface sanitizing (91.8%) and hand washing and/or sanitizing (89.8%) between all patients. Female practitioners reported practicing handwashing for at least 20 seconds, whereas male practitioners reported practicing handwashing for at least 15 seconds (P < .001). DCs were more likely to report using gloves for personal protective equipment, and LMTs were more likely to report using face masks (P < .001). Other COVID-19 procedures included limiting practice to acute care (82.5%), checking all patient temperatures (62.9%), sign-in and wait in the car (53.2% LMT vs 6.5% DC, P < .001), and prohibiting all nonpatient visitors (87.7% LMTs vs 9.4% DCs, P < .001). DCs (96.9%) and LMTs (89.9%) reported making referrals for COVID-19 testing or treatment when indicated. LMTs (82.3%) reported seeing fewer patients (P = .03), and older practitioners reported the most economic impact (P = .003) by the pandemic. Patient concerns and LMTs needing more time to perform infection control (P = .04) were reasons cited by practitioners for the reduced number of visits seen.

Conclusion

Most respondents had moderate to high compliance with guidelines on recommended infection prevention processes during fall 2020 of the COVID-19 pandemic. This assessment of compliance may be used to help guide future health education and promotion research of disease prevention and mitigation as well as physical and economic burdens faced by DCs and LMTs in Mississippi during a pandemic.

Effects of Wearing Face Masks on Cardiorespiratory Parameters at Rest and after Performing the Six-Minute Walk Test in Older Adults

The effects of wearing cloth masks and surgical masks were investigated on respiratory rate, heart rate, blood pressure, oxygen saturation and perceived exertion at rest and after performing a six-minute walk test (6MWT) in older adults. Forty older adults were recruited and randomized into six groups including wearing no mask, cloth masks and surgical masks, at rest and during the 6MWT. At rest, all subjects sat quietly wearing no mask, a cloth mask or a surgical mask. All subjects performed a 6MWT by walking as fast as possible without running while wearing no mask, a cloth mask or a surgical mask. Respiratory rate, heart rate, blood pressure, oxygen saturation and perceived exertion were assessed before and after the rest and the 6MWT. Results showed that cloth masks and surgical masks did not impact cardiorespiratory parameters at rest or after performing a 6MWT, while an increase in perceived exertion was apparent in the groups wearing surgical masks and cloth masks after performing the 6MWT (p < 0.01). Cloth masks and surgical masks did not have an impact on cardiorespiratory fitness at rest and after performing the 6MWT in older adults.

The Attractiveness of Masked Faces Is Influenced by Race and Mask Attitudes

This study tests the influence of wearing a protective face mask on the perceived attractiveness of the wearer. Participants who identified as White, and who varied in their ideological stance toward mask wearing, rated the attractiveness of facial photographs. The photos varied in baseline attractiveness (low, medium, and high), race (White and Asian), and whether or not the face was wearing a protective mask. Attitudes regarding protective masks were measured after the rating task using a survey to identify participants as either pro- or anti-mask. The results showed that masked individuals of the same race were generally rated as more attractive than unmasked individuals, but that masked individuals of another race were rated as less attractive than unmasked individuals. Moreover, pro-mask participants rated masked individuals as generally more attractive than unmasked individuals, whereas anti-maskers rated masked individuals as less attractive. A control experiment, replicating the procedure but replacing the protective masks with a partially occluding notebook, showed that these effects were mask-specific. These results demonstrate that perceived attractiveness is affected by characteristics of the viewer (attitudes toward protective masks), their relationship to the target (same or different race), and by circumstances external to both (pandemic).

Perceived importance of pandemic interventions for attending cultural events - findings from Germany

BACKGROUND

During the first waves of the COVID-19 pandemic, many cultural and sporting events were held without spectators or had to be cancelled. Therefore, several containment strategies to provide requirements for safe events were developed and tested. Nonetheless, every second (50.7%) is afraid of becoming infected on an event. We therefore investigated which hygiene and containment measures are perceived to be important from the visitor's point of view and thus might increase subjective sense of safety.

METHODS

This online study was carried out in November 2020. A total of 1,004 persons, who regularly attended events before the pandemic, took part in the study. The importance of different hygiene and containment measures was evaluated using a 5-point Likert-scale (1 "unimportant" to 5 "extremely important"). Potential statistical differences in socio-demographical aspects (age, gender, net disposable income for leisure activities) and attendance on events were tested with analyses of variance.

RESULTS

Participants perceived the use of disinfectant (M = 4.10) as the most important element of containment strategies, followed by transparent information on the hygiene strategy (M = 4.00), reduced occupancy (M = 3.98), and optimized ventilation (M = 3.97). Body temperature measurement at the entrance (M = 3.27), a negative SARS-CoV-2 test (M = 3.11), completion of a health questionnaire (M = 3.05), and abandoning breaks and catering (M = 2.98) were considered as less important. Analyses of group differences in socio-demographical aspects found abandoning breaks and catering to be more important to men than to women. This strategy is also more important to people aged 66 and above than to younger age groups (e.g., age 20-40). For women, the use of disinfectant is considerably more important. No other significant differences exist.

CONCLUSION

Combining relevant measures appears to be important to provide a safe containment strategy. Measures aimed at positively influencing people's sense of safety do not fully correspond to researched knowledge of effectiveness. There are also target group-specific differences in the rating of measures, which should be considered while preparing containment strategies. To describe the dynamic development of changes in subjective rating of containment strategies, continuing research is needed.

Face masking and COVID-19: potential effects of variolation on transmission dynamics

Face masks do not completely prevent transmission of respiratory infections, but masked individuals are likely to inhale fewer infectious particles. If smaller infectious doses tend to yield milder infections, yet ultimately induce similar levels of immunity, then masking could reduce the prevalence of severe disease even if the total number of infections is unaffected. It has been suggested that this effect of masking is analogous to the pre-vaccination practice of variolation for smallpox, whereby susceptible individuals were intentionally infected with small doses of live virus (and often acquired immunity without severe disease). We present a simple epidemiological model in which mask-induced variolation causes milder infections, potentially with lower transmission rate and/or different duration. We derive relationships between the effectiveness of mask-induced variolation and important epidemiological metrics (the basic reproduction number and initial epidemic growth rate, and the peak prevalence, attack rate and equilibrium prevalence of severe infections). We illustrate our results using parameter estimates for the original SARS-CoV-2 wild-type virus, as well as the Alpha, Delta and Omicron variants. Our results suggest that if variolation is a genuine side-effect of masking, then the importance of face masks as a tool for reducing healthcare burdens from COVID-19 may be under-appreciated.

Changes in Influenza Activity and Circulating Subtypes During the COVID-19 Outbreak in China

Background

Non-pharmaceutical interventions (NPIs) to mitigate COVID-19 can impact the circulation of influenza viruses. There is a need to describe the activity of influenza and its subtypes during the COVID-19 pandemic to aid in the development of influenza prevention and control measures in the next influenza season.

Method

Data from pathogenic surveillance performed by the Chinese National Influenza Center from January 2016 to August 2021 were extracted and stratified by type and subtype for northern China and southern China. The distribution of influenza activity and circulating subtypes were described during the COVID-19 pandemic, and data from 2016 to 2019 were used for comparisons.

Results

Influenza activity declined rapidly and then rose slowly during the COVID-19 pandemic in China. The distribution of influenza subtypes changed from A-dominant to B/Victoria-dominant after the COVID-19 outbreak.

Discussion

Whether the B/Yamagata lineage has disappeared from China deserves more attention in future virologic monitoring programs. The influenza vaccination campaign in the 2021–2022 season is an important means by which to reduce the proportion of susceptible people and limit the damage that potentially greater and earlier circulation of the virus could cause.

COVID-19 seroprevalence in Pakistan: a cross-sectional study

OBJECTIVES

This study adapted WHO's 'Unity Study' protocol to estimate the population prevalence of antibodies to SARS CoV-2 and risk factors for developing SARS-CoV-2 infection.

DESIGN

This population-based, age-stratified cross-sectional study was conducted at the level of households (HH).

PARTICIPANTS

All ages and genders were eligible for the study (exclusion criteria: contraindications to venipuncture- however, no such case was encountered). 4998 HH out of 6599 consented (1 individual per HH). The proportion of male and female study participants was similar.

PRIMARY AND SECONDARY OUTCOME MEASURES

Following were the measured outcome measures- these were different from the planned indicators (i.e. two out of the three planned indicators were measured) due to operational reasons and time constraints: -Primary indicators: Seroprevalence (population and age specific).Secondary indicators: Population groups most at risk for SARS-CoV-2-infection.

RESULTS

Overall seroprevalence of SARS-CoV-2 antibodies was 7.1%. 6.3% of individuals were IgG positive while IgM positivity was 1.9%. Seroprevalence in districts ranged from 0% (Ghotki) to 17% (Gilgit). The seroprevalence among different age groups ranged from 3.9% (0-9 years) to 10.1% (40-59 years). There were no significant differences in the overall seroprevalence for males and females. A history of contact with a confirmed COVID-19 case, urban residence and mask use were key risk factors for developing SARS-CoV-2 infection.

CONCLUSIONS

This survey provides useful estimates for seroprevalence in the general population and information on risk factors for developing SARS-CoV-2 infection in the country. It is premised that similar studies need to be replicated at the population level on a regular basis to monitor the disease and immunity patterns related to COVID-19.

Estimating data-driven coronavirus disease 2019 mitigation strategies for safe university reopening

After one pandemic year of remote or hybrid instructional modes, universities struggled with plans for an in-person autumn (fall) semester in 2021. To help inform university reopening policies, we collected survey data on social contact patterns and developed an agent-based model to simulate the spread of severe acute respiratory syndrome coronavirus 2 in university settings. Considering a reproduction number of R₀ = 3 and 70% immunization effectiveness, we estimated that at least 80% of the university population immunized through natural infection or vaccination is needed for safe university reopening with relaxed non-pharmaceutical interventions (NPIs). By contrast, at least 60% of the university population immunized through natural infection or vaccination is needed for safe university reopening when NPIs are adopted. Nevertheless, attention needs to be paid to large-gathering events that could lead to infection size spikes. At an immunization coverage of 70%, continuing NPIs, such as wearing masks, could lead to a 78.39% reduction in the maximum cumulative infections and a 67.59% reduction in the median cumulative infections. However, even though this reduction is very beneficial, there is still a possibility of non-negligible size outbreaks because the maximum cumulative infection size is equal to 1.61% of the population, which is substantial.

Adherence to facemask use in public places during the autumn-winter 2020 COVID-19 lockdown in Greece: observational data

BACKGROUND

Wearing facemasks is of proven efficacy as a public health protective measure against COVID-19. Currently there are no observational data concerning the wearing of facemasks and the adherence to guidelines concerning their handling.

METHODS

Registration of the way passers-by were wearing facemasks at 26 different locations of five major cities in Greece. The results were correlated with the rate of COVID-19 deaths in the region.

RESULTS

In total, 119,433 passers-by were registered, 57,043 females (47.8%) and 62,390 males (52.2%). From the total sample, 81.1% were wearing the mask properly, 10.8% had their nose out, 6.2% were wearing it under the jaw, and 1.9% had no mask at all . There was a significant difference between males and females concerning any use of mask. Inappropriate use of was correlated with COVID-19 death rate in the studied region.

CONCLUSION

Our findings suggest that under conditions of mandatory wearing and in central locations of major cities, during walking, proper use of masks is suboptimal, but still contributes with some protection. Fear and risk perception seem to be strong factors contributing to adherence to proper mask wearing.

Increasing Receptivity to COVID-19 Public Health Messages with Self-Affirmation and Self vs. Other Framing

There remains an urgent need for effective communication about the importance of widespread adherence to behavioral recommendations to control the COVID-19 pandemic that will also reduce resistance to such guidance. We examined two strategies for COVID-19 communication- (1) self-affirmation (reflecting on a personal value in order to boost self-integrity and reduce defensiveness to potentially threatening information); and (2) manipulating self/other message framing - and moderation of these strategies by COVID-19 risk. 600 participants (M_age = 32.55, 51% female) were recruited for an online study and, after assessment of risk factors for severe COVID-19 infection, were exposed to the experimental manipulations. Three classes of defensive responses were considered as outcomes of interest: reactance, attitudinal responses, and behavioral responses. We found that participants derogated the self-focused message more than the other-focused message. Further, other-focused messaging and/or self-affirmation were more likely to elicit positive responses among individuals at higher risk for COVID-19 complications. Our findings suggest having individuals affirm values prior to viewing COVID-19 messages, and framing messages in terms of the importance of protecting others, may be beneficial strategies for encouraging responsiveness - particularly if the targets of such messages are at risk of COVID-19 complications themselves.

COVID-19 in Rural America: Impacts of Politics and Disadvantage

Early in the COVID-19 pandemic, people living in cities were much more likely than rural residents to become infected with and die from the virus. Beginning in the summer of 2020, however, the proportional increase in virus spread became much greater in rural areas. By March 2021, per capita cases and deaths were greater in nonmetro than in metro areas. Multi-variate regression analysis found that political views were the most important variable explaining per capita COVID-19 cases, while measures of disadvantage were the best predictors of COVID-19 deaths. Counties with high proportions of Trump voters had higher per capita cases, and in nonmetro areas, these counties had higher death rates. Overall, the best predictor of COVID-19 death rates is low levels of educational attainment, high poverty rates, and high minority populations.

Face mask fit hacks: Improving the fit of KN95 masks and surgical masks with fit alteration techniques

Introduction

During the course of the COVID-19 pandemic, there have been suggestions that various techniques could be employed to improve the fit and, therefore, the effectiveness of face masks. It is well recognized that improving fit tends to improve mask effectiveness, but whether these fit modifiers are reliable remains unexplored. In this study, we assess a range of common “fit hacks” to determine their ability to improve mask performance.

Methods

Between July and September 2020, qualitative fit testing was performed in an indoor living space. We used quantitative fit testing to assess the fit of both surgical masks and KN95 masks, with and without ‘fit hacks’, on four participants. Seven fit hacks were evaluated to assess impact on fit. Additionally, one participant applied each fit hack multiple times to assess how reliable hacks were when reapplied. A convenience of four participants took part in the study, three females and one male with a head circumference range of 54 to 60 centimetres.

Results and discussion

The use of pantyhose, tape, and rubber bands were effective for most participants. A pantyhose overlayer was observed to be the most effective hack. High degrees of variation were noted between participants. However, little variation was noted within participants, with hacks generally showing similar benefit each time they were applied on a single participant. An inspection of the fit hacks once applied showed that individual facial features may have a significant impact on fit, especially the nose bridge.

Conclusions

Fit hacks can be used to effectively improve the fit of surgical and KN95 masks, enhancing the protection provided to the wearer. However, many of the most effective hacks are very uncomfortable and unlikely to be tolerated for extended periods of time. The development of effective fit-improvement solutions remains a critical issue in need of further development.

Severe Acute Respiratory Syndrome Coronavirus 2 Nosode: A Potential Alternative Vaccine Platform

Besides conventional vaccinations, viable alternatives are needed to elicit an immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We propose and highlight the value of a homeopathic approach known as the "nosode" for the prevention of coronavirus disease-2019 (COVID-19). Nosode is an extract prepared from disease-affected tissues which is subsequently processed and administered as an antidote for the same medical condition. This concept might be a crucial therapeutic approach for viral infections since infected tissues contain a wide range of important viral antigens that could induce a functional host response via immunological sensitization. Thereby, nosode preparation produced from SARS-CoV-2-affected tissues may provide protection against COVID-19. "SARS-CoV-2 nosode" warrants more scientific investigation as a viable alternative vaccination platform. Keywords: COVID-19, Nosode, SARS-CoV-2, Variolation.

Personality and compliance with COVID-19 protective measures among older Americans: Moderating effects of age, gender, and race/ethnicity

Following the growing evidence that personality is related to various health behaviors, we examined whether personality traits were related to compliance with COVID-19 protective measures and evaluated the extent to which associations were moderated by age, gender, or race/ethnicity among older adults during a summer 2020 surge of COVID-19 cases in the United States. Data were from the 2020 Health and Retirement Study COVID-19 module. Multivariate ordinary least squares regression analyses were computed adjusting for health, psychosocial, and sociodemographic factors. Results indicated the significant associations between personality traits and compliance with COVID-19 measures varied by age, gender, and race/ethnicity. Specifically, the associations of agreeableness with wearing a mask and frequent handwashing were less pronounced among older compared with younger individuals. The association between extraversion and wearing masks was stronger for men than for women. The associations of agreeableness with handwashing and physical distancing were weaker for Hispanic older adults, whereas the associations of extraversion with physical distancing and using sanitizers were stronger for Hispanic older adults than for their non-Hispanic White counterparts. Implications regarding behavioral science underlying the current pandemic and future public health crises are discussed.

The Effects of Wearing a Medical Mask on the Masticatory and Neck Muscle Activity in Healthy Young Women

The objective of this study was to analyze the influence of wearing a medical mask on masticatory and neck muscle activity in healthy young women. We recruited 66 healthy women aged from 18 to 30 years (mean 23.6 ± 2.3 years). The temporalis anterior (TA), the superficial part of the masseter muscle (MM), the anterior bellies of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) potentials were recorded at rest and during functional activity using an eight-channel device for surface electromyography—BioEMG III^TM. There was a statistically significant decrease in mean TA activity during medical mask measurement compared to no mask examination at rest (2.16 µV vs. 2.58 µV; p = 0.05; ES = 0.2). Significant decreases in resting RMS values were also observed during the medical mask phase in comparison to no mask examination concerning the left MM (1.75 µV vs. 2.17 µV; p = 0.01; ES = 0.3), and mean bioelectrical activity of the MM (1.81 µV vs. 2.15 µV; p = 0.02; ES = 0.2). The differences between the two conditions did not reach the assumed significance level (p > 0.05) in terms of other indices. Wearing a medical mask has a small effect on decreasing the resting potentials of the temporalis anterior and masseter muscles without changing the parameters of activity and asymmetry within the stomatognathic system.

A Genealogical Study of Facemasks in China: From Hygienic Modernity to Care

Despite the omnipresence of facemasks in the ongoing COVID-19 pandemic, recent studies on their sociopolitical aspects remain insufficient. This article conducts a genealogical study that investigates the emergence of two differing masking strategies in two epidemic events in Chinese history. First, during the Manchurian plague 1910/11, it shows how the germ theory and historical anecdotes made anti-plague masks thinkable and practicable as a solution not only for airborne contagion but also for the biopolitical problem of ‘unhygienic’ population. In the second part, the analytical focus is shifted to the emergence of collective mask-wearing practices during SARS 2002/03 from the vantage point of subjectification. Facemasks then became a symbol of care in the neoliberal regime of responsibilization. This article concludes by arguing for a rethinking of facemasks as actants who actively participate in the constitution of the world we share.

Evaluating the Association of Face Covering Mandates on COVID-19 Severity by State

Objective:

During the COVID-19 pandemic in the United States, mitigation measures were implemented on a state-by-state basis. Governors were responsible for establishing interventions appropriate for their states and the timing of implementation. This paper evaluated the association between the presence and timing of a mask mandate and the severity of the COVID-19 epidemic by state.

Methods:

The states were divided into 3 categories based on when the governors of each state implemented a mask mandate: Early (mask mandate implemented between March 2020 and June 2020), Late (July 2020-December 2020), and Never (no mask mandate implemented). The rates of hospitalizations and mortality (per 100 000) were assessed at the different time points during the pandemic across these categories from March to December 2020.

Results:

The mortality rates across all 3 groups were observed to be highest in the beginning and toward the end of the pandemic in 2020 with the peak observed in the Early group between April and May 2020. Also, the rates of hospitalization increased steadily across all groups. The Early mask group was comprised of 86.7% and 13.3% states with Democratic and Republican governors respectively, and no states in the Never category had Democratic governors.

Conclusion:

These results support the benefit of implementing a mask mandate to minimize the impact of the COVID-19 pandemic and the role of political affiliation of governors on that impact.

Shift in Clinical Profile of Hospitalized Pneumonia in Children in the Non-pharmaceutical Interventions Period During the COVID-19 Pandemic: A Prospective Multicenter Study

Non-pharmaceutical interventions (NPIs) against coronavirus disease 2019 were implemented in March 2020. These measures were followed by a major impact on viral and non-viral diseases. We aimed to assess the impact of NPI implementation in France on hospitalized community-acquired pneumonia (hCAP) frequency and the clinical and biological characteristics of the remaining cases in children. We performed a quasi-experimental interrupted time-series analysis. Between June 2014 and December 2020, eight pediatric emergency departments throughout France reported prospectively all cases of hCAP in children from age 1 month to 15 years. We estimated the impact on the monthly number of hCAP using segmented linear regression with autoregressive error model. We included 2,972 hCAP cases; 115 occurred during the NPI implementation period. We observed a sharp decrease in the monthly number of hCAP after NPI implementation [-63.0% (95 confidence interval, -86.8 to -39.2%); p < 0.001]. Children with hCAP were significantly older during than before the NPI period (median age, 3.9 vs. 2.3 years; p < 0.0001), and we observed a higher proportion of low inflammatory marker status (43.5 vs. 33.1%; p = 0.02). Furthermore, we observed a trend with a decrease in the proportion of cases with pleural effusion (5.3% during the NPI period vs. 10.9% before the NPI; p = 0.06). NPI implementation during the COVID-19 (coronavirus disease 2019) pandemic led not only to a strong decrease in the number of hCAP cases but also a modification in the clinical profile of children affected, which may reflect a change in pathogens involved.

Control of airborne infectious disease in buildings: Evidence and research priorities

The evolution of SARS-CoV-2 virus has resulted in variants likely to be more readily transmitted through respiratory aerosols, underscoring the increased potential for indoor environmental controls to mitigate risk. Use of tight-fitting face masks to trap infectious aerosol in exhaled breath and reduce inhalation exposure to contaminated air is of critical importance for disease control. Administrative controls including the regulation of occupancy and interpersonal spacing are also important, while presenting social and economic challenges. Indoor engineering controls including ventilation, exhaust, air flow control, filtration, and disinfection by germicidal ultraviolet irradiation can reduce reliance on stringent occupancy restrictions. However, the effects of controls-individually and in combination-on reducing infectious aerosol transfer indoors remain to be clearly characterized to the extent needed to support widespread implementation by building operators. We review aerobiologic and epidemiologic evidence of indoor environmental controls against transmission and present a quantitative aerosol transfer scenario illustrating relative differences in exposure at close-interactive, room, and building scales. We identify an overarching need for investment to implement building controls and evaluate their effectiveness on infection in well-characterized and real-world settings, supported by specific, methodological advances. Improved understanding of engineering control effectiveness guides implementation at scale while considering occupant comfort, operational challenges, and energy costs.

The Infectious Dose Shapes Vibrio cholerae Within-Host Dynamics

During infection, the rates of pathogen replication, death, and migration affect disease progression, dissemination, transmission, and resistance evolution. Here, we follow the population dynamics of Vibrio cholerae in a mouse model by labeling individual bacteria with one of >500 unique, fitness-neutral genomic tags. Using the changes in tag frequencies and CFU numbers, we inform a mathematical model that describes the within-host spatiotemporal bacterial dynamics. This allows us to disentangle growth, death, forward, and retrograde migration rates continuously during infection. Our model has robust predictive power across various experimental setups. The population dynamics of V. cholerae shows substantial spatiotemporal heterogeneity in replication, death, and migration. Importantly, we find that the niche available to V. cholerae in the host increases with inoculum size, suggesting cooperative effects during infection. Therefore, it is not enough to consider just the likelihood of exposure (50% infectious dose) but rather the magnitude of exposure to predict outbreaks. IMPORTANCE Determining the rates of bacterial migration, replication, and death during infection is important for understanding how infections progress. Separately measuring these rates is often difficult in systems where multiple processes happen simultaneously. Here, we use next-generation sequencing to measure V. cholerae migration, replication, death, and niche size along the mouse gastrointestinal tract. We show that the small intestine of the mouse is a heterogeneous environment, and the population dynamic characteristics change substantially between adjacent gut sections. Our approach also allows us to characterize the effect of inoculum size on these processes. We find that the niche size in mice increases with the infectious dose, hinting at cooperative effects in larger inocula. The dose-response relationship between inoculum size and final pathogen burden is important for the infected individual and is thought to influence the progression of V. cholerae epidemics.

HIV Diagnosis and the Clinical Course of COVID-19 Among Patients Seeking Care Within the New York City Public Hospital System During the Initial Pandemic Peak

Reports conflict on how HIV infection influences the clinical course of COVID-19. The New York City (NYC) public hospital system provides care for over 14,000 people with HIV, was central in responding to the COVID-19 pandemic, and is therefore in a unique position to evaluate the intersection of these concurrent infections. Retrospective chart review of patients presenting to NYC Health and Hospitals (NYC H+H) diagnosed with COVID-19 infection from March 1, 2020, through April 28, 2020, compared people living with HIV (PLWH) and a propensity-matched (PM) control group of patients without HIV to evaluate associations between HIV status and COVID-19 outcomes. Two hundred thirty-four PLWH presented for COVID-19 testing and 110 (47%) were diagnosed with COVID-19. Among 17,413 patients with COVID-19 and without HIV, 1:n nearest neighbor propensity score matching identified 194 patients matched on age, sex, race, and any comorbidity. In the sample with COVID-19 (N = 304), PLWH (9.1%) had lower rates of mortality than controls [19.1%; PM odds ratio (PM-OR): 0.41, 95% confidence interval (CI): 0.19-0.86]. Among hospitalized COVID-19 patients (N = 179), HIV infection was associated with lower rates of mechanical ventilation (PM-OR: 0.31, 95% CI: 0.11-0.84) and mortality (PM-OR: 0.40, 95% CI: 0. 17-0.95). In the extended pandemic period through April 2021, aggregate data by HIV status suggested elevated hospitalization and mortality rates in PLWH versus people without HIV. These results suggest that the direct biological impacts of the HIV virus do not negatively influence COVID-19-related outcomes when controlling for comorbidity and demographic variables.

COVID-19 severity determinants inferred through ecological and epidemiological modeling

Understanding variations in the severity of infectious diseases is essential for planning proper mitigation strategies. Determinants of COVID-19 clinical severity are commonly assessed by transverse or longitudinal studies of the fatality counts. However, the fatality counts depend both on disease clinical severity and transmissibility, as more infected also lead to more deaths. Instead, we use epidemiological modeling to propose a disease severity measure that accounts for the underlying disease dynamics. The measure corresponds to the ratio of population-averaged mortality and recovery rates (m/r), is independent of the disease transmission dynamics (i.e., the basic reproduction number), and has a direct mechanistic interpretation. We use this measure to assess demographic, medical, meteorological, and environmental factors associated with the disease severity. For this, we employ an ecological regression study design and analyze different US states during the first disease outbreak. Principal Component Analysis, followed by univariate, and multivariate analyses based on machine learning techniques, is used for selecting important predictors. The usefulness of the introduced severity measure and the validity of the approach are confirmed by the fact that, without using prior knowledge from clinical studies, we recover the main significant predictors known to influence disease severity, in particular age, chronic diseases, and racial factors. Additionally, we identify long-term pollution exposure and population density as not widely recognized (though for the pollution previously hypothesized) significant predictors. The proposed measure is applicable for inferring severity determinants not only of COVID-19 but also of other infectious diseases, and the obtained results may aid a better understanding of the present and future epidemics. Our holistic, systematic investigation of disease severity at the human-environment intersection by epidemiological dynamical modeling and machine learning ecological regressions is aligned with the One Health approach. The obtained results emphasize a syndemic nature of COVID-19 risks.

Spatially distributed infection increases viral load in a computational model of SARS-CoV-2 lung infection

A key question in SARS-CoV-2 infection is why viral loads and patient outcomes vary dramatically across individuals. Because spatial-temporal dynamics of viral spread and immune response are challenging to study in vivo, we developed Spatial Immune Model of Coronavirus (SIMCoV), a scalable computational model that simulates hundreds of millions of lung cells, including respiratory epithelial cells and T cells. SIMCoV replicates viral growth dynamics observed in patients and shows how spatially dispersed infections can lead to increased viral loads. The model also shows how the timing and strength of the T cell response can affect viral persistence, oscillations, and control. By incorporating spatial interactions, SIMCoV provides a parsimonious explanation for the dramatically different viral load trajectories among patients by varying only the number of initial sites of infection and the magnitude and timing of the T cell immune response. When the branching airway structure of the lung is explicitly represented, we find that virus spreads faster than in a 2D layer of epithelial cells, but much more slowly than in an undifferentiated 3D grid or in a well-mixed differential equation model. These results illustrate how realistic, spatially explicit computational models can improve understanding of within-host dynamics of SARS-CoV-2 infection.