Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh

Face masks to prevent transmission of respiratory infections: Systematic review and meta-analysis of randomized controlled trials on face mask use

OBJECTIVES

To examine the use of face mask intervention in mitigating the risk of spreading respiratory infections and whether the effect of face mask intervention differs in different exposure settings and age groups.

DESIGN

Systematic review and meta-analysis. We evaluated the risk of bias using the Cochrane Risk of Bias 2 tool (ROB2).

DATA SOURCES

We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were searched for randomized controlled trials investigating the effect of face masks on respiratory infections published between 1981 and February 9, 2022. We followed the PRISMA 2020 guidelines.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included randomized controlled trials investigating the use of face mask intervention in mitigating the risk of spreading respiratory infections across different exposure settings.

RESULTS

We identified 2,400 articles for screening. 18 articles passed the inclusion criteria for both evidence synthesis and meta-analysis. There were N = 189,145 individuals in the face mask intervention arm and N = 173,536 in the control arm, and the follow-up times ranged from 4 days to 19 months. Our results showed between-study heterogeneity (p < 0.0001). While there was no statistically significant association over all studies when the covariate unadjusted intervention effect estimates were used (RR = 0.977 [0.858-1.113], p = 0.728), our subgroup analyses revealed that a face mask intervention reduced respiratory infections in the adult subgroup (RR = 0.8795 [0.7861-0.9839], p = 0.0249) and in a community setting (RR = 0.890 [0.812-0.975], p = 0.0125). Furthermore, our leave-one-out analysis found that one study biased the results towards a null effect. Consequently, when using covariate adjusted odds ratio estimates to have a more precise effect estimates of the intervention effect to account for differences at the baseline, the results showed that a face mask intervention did reduce respiratory infections when the biasing study was excluded from the analysis (OR = 0.8892 [0.8061-0.9810], p = 0.0192).

CONCLUSION

Our findings support the use of face masks particularly in a community setting and for adults. We also observed substantial between-study heterogeneity and varying adherence to protocol. Notably, many studies were subject to contamination bias thus affecting the efficacy of the intervention, that is when also some controls used masks or when the intervention group did not comply with mask use leading to a downward biased effect of treatment receipt and efficacy.

TRIAL REGISTRATION

PROSPERO registration number CRD42020205523.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial

BACKGROUND

It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators.

OBJECTIVE

To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care.

DESIGN

Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643).

SETTING

29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022.

PARTICIPANTS

1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19.

INTERVENTION

Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site.

MEASUREMENTS

The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test.

RESULTS

In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group.

LIMITATION

Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination.

CONCLUSION

Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

Vaccination rates and COVID outcomes across U.S. states

Rates of COVID deaths, hospitalizations, and cases differ markedly across U.S. states, as do rates of vaccination. This study uses cross-state regressions to assess impacts of vaccinations on COVID outcomes. A number of familiar issues arise concerning cross-sectional regressions, including omitted variables, behavioral responses to vaccination, and reverse causation. The benefits from a field context and from the broad range of observed variations suggest the value from dealing with these issues. Results reveal sizable negative effects of vaccination on deaths, hospitalizations, and cases up to early December 2021, although vaccine efficacy seems to wane over time. The findings for deaths apply to all-cause excess mortality as well as COVID-related mortality. The estimates imply that one expected life saved requires 248 additional doses, with a marginal cost around $55000, far below typical estimates of the value of a statistical life. Results since December 2021 suggest smaller effects of vaccinations on deaths and, especially, hospitalizations and cases, possibly because of diminished effectiveness of vaccines against new forms of the virus, notably the omicron variant. A further possibility is that confidence engendered by vaccinations motivated individuals and governments to lessen non-pharmaceutical interventions, such as masking and social distancing.

Use of surveillance data to elucidate household clustering of SARS-CoV-2 in Fulton County, Georgia a major metropolitan area

BACKGROUND

Households are important for SARS-CoV-2 transmission due to high intensity exposure in enclosed spaces over prolonged durations. We quantified and characterized household clustering of COVID-19 cases in Fulton County, Georgia.

METHODS

We used surveillance data to identify all confirmed COVID-19 cases in Fulton County. Household clustered cases were defined as cases with matching residential address. We described the proportion of COVID-19 cases that were clustered, stratified by age over time and explore trends in age of first diagnosed case within households and subsequent household cases.

RESULTS

Between June 1, 2020 and October 31, 2021, 31,449(37%) of 106,233 cases were clustered in households. Children were the most likely to be in household clusters than any other age group. Initially, children were rarely (∼ 10%) the first cases diagnosed in the household but increased to almost 1 of 3 in later periods.

DISCUSSION

One-third of COVID-19 cases in Fulton County were part of a household cluster. Increasingly children were the first diagnosed case, coinciding with temporal trends in vaccine roll-out among the elderly and the return to in-person schooling in Fall 2021. Limitations include restrictions to cases with a valid address and unit number and that the first diagnosed case may not be the infection source for the household.

Effect of Wearing Glasses on Risk of Infection With SARS-CoV-2 in the Community: A Randomized Clinical Trial

Importance

Observational studies have reported an association between the use of eye protection and reduced risk of infection with SARS-CoV-2 and other respiratory viruses, but, as with most infection control measures, no randomized clinical trials have been conducted.

Objectives

To evaluate the effectiveness of wearing glasses in public as protection against being infected with SARS-CoV-2 and other respiratory viruses.

Design, Setting, and Participants

A randomized clinical trial was conducted in Norway from February 2 to April 24, 2022; all adult members of the public who did not regularly wear glasses, had no symptoms of COVID-19, and did not have COVID-19 in the last 6 weeks were eligible.

Intervention

Wearing glasses (eg, sunglasses) when close to others in public spaces for 2 weeks.

Main Outcomes and Measures

The primary outcome was a positive COVID-19 test result reported to the Norwegian Surveillance System for Communicable Diseases. Secondary outcomes included a positive COVID-19 test result and respiratory infection based on self-report. All analyses adhered to the intention-to-treat principle.

Results

A total of 3717 adults (2439 women [65.6%]; mean [SD] age, 46.9 [15.1] years) were randomized. All were identified and followed up in the registries, and 3231 (86.9%) responded to the end of study questionnaire. The proportions with a reported positive COVID-19 test result in the national registry were 3.7% (68 of 1852) in the intervention group and 3.5% (65 of 1865) in the control group (absolute risk difference, 0.2%; 95% CI, -1.0% to 1.4%; relative risk, 1.10; 95% CI, 0.75-1.50). The proportions with a positive COVID-19 test result based on self-report were 9.6% (177 of 1852) in the intervention group and 11.5% (214 of 1865) in the control group (absolute risk difference, -1.9%; 95% CI, -3.9% to 0.1%; relative risk, 0.83; 95% CI, 0.69-1.00). The risk of respiratory infections based on self-reported symptoms was lower in the intervention group (30.8% [571 of 1852]) than in the control group (34.1% [636 of 1865]; absolute risk difference, -3.3%; 95% CI, -6.3% to -0.3%; relative risk, 0.90; 95% CI, 0.82-0.99).

Conclusions and Relevance

In this randomized clinical trial, wearing glasses in the community was not protective regarding the primary outcome of a reported positive COVID-19 test. However, results were limited by a small sample size and other issues. Glasses may be worth considering as one component in infection control, pending further studies.

Trial Registration

ClinicalTrials.gov Identifier: NCT05217797.

Prevalence and predictors of anti-SARS-CoV-2 serology in a highly vulnerable population of Rio de Janeiro: A population-based serosurvey

Background

COVID-19 serosurveys allow for the monitoring of the level of SARS-CoV-2 transmission and support data-driven decisions. We estimated the seroprevalence of anti-SARS-CoV-2 antibodies in a large favela complex in Rio de Janeiro, Brazil.

Methods

A population-based panel study was conducted in Complexo de Manguinhos (16 favelas) with a probabilistic sampling of participants aged ≥1 year who were randomly selected from a census of individuals registered in primary health care clinics that serve the area. Participants answered a structured interview and provided blood samples for serology. Multilevel regression models (with random intercepts to account for participants’ favela of residence) were used to assess factors associated with having anti-S IgG antibodies. Secondary analyses estimated seroprevalence using an additional anti-N IgG assay.

Findings

4,033 participants were included (from Sep/2020 to Feb/2021, 22 epidemic weeks), the median age was 39·8 years (IQR:21·8-57·7), 61% were female, 41% were mixed-race (Pardo) and 23% Black. Overall prevalence was 49·0% (95%CI:46·8%-51·2%) which varied across favelas (from 68·3% to 31·4%). Lower prevalence estimates were found when using the anti-N IgG assay. Odds of having anti-S IgG antibodies were highest for young adults, and those reporting larger household size, poor adherence to social distancing and use of public transportation.

Interpretation

We found a significantly higher prevalence of anti-S IgG antibodies than initially anticipated. Disparities in estimates obtained using different serological assays highlight the need for cautious interpretation of serosurveys estimates given the heterogeneity of exposure in communities, loss of immunological biomarkers, serological antigen target, and variant-specific test affinity.

Funding

Fundação Oswaldo Cruz, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), the European Union's Horizon 2020 research and innovation programme, Royal Society, Serrapilheira Institute, and FAPESP.

Health misinformation: protocol for a hybrid concept analysis and development

Background: Misinformation represents a serious and growing concern in public health; and has attracted much interest from researchers, media, and the public over recent years. Despite increased concern about the impacts of misinformation on health and wellbeing, however, the concept of health misinformation remains underdeveloped. In particular, there is a need to clarify how certain types of health information come to be designated as “misinformation,” what characteristics are associated with this classification, and how the concept of misinformation is applied in public health interventions. Aim: Developing a shared understanding of what it means for health information to be “misinformation” is an important first step to accurately identifying at-risk groups, clarifying pathways of vulnerability, and agreeing goals for intervention. It will also help to ensure that misinformation interventions are accessible, acceptable, and of benefit to the populations to which they are directed. We will therefore examine the characteristics, measurement, and applications of misinformation in public health. Methods: We will undertake a hybrid concept analysis, following a framework from Schwartz-Barcott & Kim (2000). This framework comprises three phases: a theoretical phase, fieldwork phase, and final analysis phase. In the theoretical phase, a search of seven electronic citation databases (PsycInfo, socINDEX, JSTOR, CINAHL, Scopus, PubMed, and ScienceDirect) will be conducted in order to identify original research, review, and theoretical papers, published in English between 2016 and 2022, which examine “health misinformation.” Data from the literature will be synthesised using evolutionary concept analysis methods from Rodgers (2000). In the fieldwork phase, a purposive sampling strategy will be employed to recruit stakeholders for participation in semi-structured interviews. Interviews will be analysed using thematic analysis. The final phase will integrate findings from the theoretical and fieldwork analyses.

Clinical trial research agenda on COVID-19 - the first two years in Germany and beyond

BACKGROUND

We have followed the COVID-19 clinical trial research agenda from the beginning using the COVID-evidence.org platform. Now, two years after the COVID-19 pandemic started, our aim was to re-examine this research agenda with the latest data to provide a global perspective on the research landscape with a focus on Germany.

METHODS

We reviewed and updated previously published data on the COVID-19 clinical research agenda as of 28February 2022 focusing on randomized trials. We used the COVID-evidence.org platform including registry entries from ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform as well as publications from the Living OVerview of Evidence platform for COVID-19 (L·OVE).

RESULTS

Two years on from the pandemic outbreak, there were 4,673 registered trials. The majority of these trials have remained small with a median of 120 planned participants (IQR 60-320). In the first hundred days of the pandemic most of them (50%) had been registered in China. More than two years later, the five countries with the most registered trials (alone or within a framework of international collaborations) were the USA (825 trials; 18%), Iran (619 trials; 13%), India (566 trials; 12%), China (353 trials; 8%), and Spain (309 trials; 7%). Only 119 trials were reported to have a study site in Germany (2.5% of the registered trials). Of the 4,673 trials registered, 15% (694 trials) had published their results by February 2022. The clinical research agenda has been marked by both successes, such as the large RECOVERY trial providing evidence on 10 treatments for COVID-19 including over 45,000 patients as of February 2022, and failures: worldwide only 57 randomized trials have been registered over two years that aimed to assess non-pharmaceutical interventions (e.g., face mask policies and lockdown measures) to prevent COVID-19, and only 11 of them had published results informing decisions that have an impact on the life of billions of people worldwide.

CONCLUSIONS

The COVID-19 clinical research agenda has highlighted the substantial effort of the research community but also the challenges of the clinical research ecosystem. Most importantly, it has shed light on the ability to circumvent traditional barriers and to make trials more useful even under extraordinary conditions. The time to learn our lessons and apply them is now, and the time to demonstrate how we have improved the system is before the next pandemic.

Adherence to COVID -19 protective practices in Ethiopia: Use and predictors of face mask-wearing

Introduction

The Ethiopian Ministry of Health strongly recommends that anyone, regardless of vaccination status, wears a standard face mask consistently when in public. This study aimed to assess the self-reported use and predictors of wearing face masks in the general population in Ethiopia.

Methods

This was a population-based cross-sectional study using a telephone survey. Adults living in Ethiopia were randomly selected from the Ethio Telecom list of mobile phone numbers and interviewed about their mask-wearing practice and individual and household-level factors that could impact on the use of face masking. Multivariable logistic regression was used to measure associations.

Results

A total of 614 participants were interviewed from September to November 2021. The prevalence of self-reported face mask use when in public was 81.1%. Living outside Addis Ababa, including Oromia [adjusted odds ratio [(AOR) 0.30, 95% confidence interval (CI) (0.14, 0.63)], Amhara [AOR 0.11, 95% CI (0.05, 0.23)], and Southern Nations, Nationalities and People's Region [AOR 0.31, 95% CI (0.12-0.79)] and being divorced or widowed [AOR 0.18, 95% CI (0.06, 0.62)] were found to be inversely associated with face mask use. Female gender [AOR 1.91, 95% CI (1.02, 3.58)] and older age [age ≥ 50, AOR 2.96, 95% CI (1.09-7.97)] were positively associated with the use of face masks. Attending social events [AOR 0.51, 95% CI (0.31-0.82)], was negatively associated with the use of face masks.

Conclusion

Self-reported use of face masks was relatively high nationally, but inconsistent among different regions and demographics. The findings imply that policies and messaging campaigns may need to focus on specific populations and behaviors in this ongoing pandemic.

Sociocultural determinants of global mask-wearing behavior

Behavioral responses influence the trajectories of epidemics. During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) reduced pathogen transmission and mortality worldwide. However, despite the global pandemic threat, there was substantial cross-country variation in the adoption of protective behaviors that is not explained by disease prevalence alone. In particular, many countries show a pattern of slow initial mask adoption followed by sharp transitions to high acceptance rates. These patterns are characteristic of behaviors that depend on social norms or peer influence. We develop a game-theoretic model of mask wearing where the utility of wearing a mask depends on the perceived risk of infection, social norms, and mandates from formal institutions. In this model, increasing pathogen transmission or policy stringency can trigger social tipping points in collective mask wearing. We show that complex social dynamics can emerge from simple individual interactions and that sociocultural variables and local policies are important for recovering cross-country variation in the speed and breadth of mask adoption. These results have implications for public health policy and data collection.

Lessons from the health policies for children during the pandemic in Japan

It is everyone's desire to seek the sound growth of children through food education and there is a critical need for fostering an environment for this purpose. Health policies are important for this support. To the present, the Japanese society has been greatly disrupted by COVID-19 pandemic. "Stay at home", "mokusyoku (silent eating)", and mask wearing were encouraged in nationwide campaigns as public health measures to combat COVID-19. There are some papers reporting negative effects of "stay at home" and lockdowns such as weight gain, decrease in physical activities and change in eating habits. In Japan, while benefits and advantages of food education during mealtime were previously well studied, the "mokusyoku" rule may directly run counter to this food education. Moreover, there are several reports showing that nutrients might contribute to prevention of infectious diseases. Japanese children were also encouraged to wear masks all day long. The results of the clinical research, especially randomized control trials, show limited protective effect of masks. On the other hand, negative outcomes of the masks were reported in various scenes. This review focuses on these topics and arousing reconsideration for a better environment for children.

Transmission of SARS-CoV-2 in a primary school setting with and without public health measures using real-world contact data: A modelling study

Background

Stringent public health measures have been shown to influence the transmission of SARS-CoV-2 within school environments. We investigated the potential transmission of SARS-CoV-2 in a primary school setting with and without public health measures, using fine-grained physical positioning traces captured before the COVID-19 pandemic.

Methods

Approximately 172.63 million position data from 98 students and six teachers from an open-plan primary school were used to predict a potential transmission of SARS-CoV-2 in primary school settings. We first estimated the daily average number of contacts of students and teachers with an infected individual during the incubation period. We then used the Reed-Frost model to estimate the probability of transmission per contact for the SARS-CoV-2 Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron variant (B.1.1.529). Finally, we built a binomial distribution model to estimate the probability of onward transmission in schools with and without public health measures, including face masks and physical distancing.

Results

An infectious student would have 49.1 (95% confidence interval (CI) = 46.1-52.1) contacts with their peers and 2.00 (95% CI = 1.82-2.18) contacts with teachers per day. An infectious teacher would have 47.6 (95% CI = 45.1-50.0) contacts with students and 1.70 (95% CI = 1.48-1.92) contacts with their colleague teachers per day. While the probability of onward SARS-CoV-2 transmission was relatively low for the Alpha and Delta variants, the risk increased for the Omicron variant, especially in the absence of public health measures. Onward teacher-to-student transmission (88.9%, 95% CI = 88.6%-89.1%) and teacher-to-teacher SARS-CoV-2 transmission (98.4%, 95% CI = 98.5%-98.6%) were significantly higher for the Omicron variant without public health measures in place.

Conclusions

Our findings illustrate that, despite a lower frequency of close contacts, teacher-to-teacher close contacts demonstrated a higher risk of transmission per contact of SARS-CoV-2 compared to student-to-student close contacts. This was especially significant with the Omicron variant, with onward transmission more likely occurring from teacher index cases than student index cases. Public health measures (eg, face masks and physical distance) seem essential in reducing the risk of onward transmission within school environments.

Public health ethics: critiques of the "new normal"

The global response to the recent coronavirus pandemic has revealed an ethical crisis in public health. This article analyses key pandemic public health policies in light of widely accepted ethical principles: the need for evidence, the least restrictive/harmful alternative, proportionality, equity, reciprocity, due legal process, and transparency. Many policies would be considered unacceptable according to pre-pandemic norms of public health ethics. There are thus significant opportunities to develop more ethical responses to future pandemics. This paper serves as the introduction to this Special Issue of Monash Bioethics Review and provides background for the other articles in this collection.

Re-analysis on the statistical sampling biases of a mask promotion trial in Bangladesh: a statistical replication

A recent randomized trial evaluated the impact of mask promotion on COVID-19-related outcomes. We find that staff behavior in both unblinded and supposedly blinded steps caused large and statistically significant imbalances in population sizes. These denominator differences constitute the rate differences observed in the trial, complicating inferences of causality.

The impact of face-mask mandates on all-cause mortality in Switzerland: a quasi-experimental study

Background

Whereas there is strong evidence that wearing a face mask is effective in reducing the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), evidence on the impact of mandating the wearing of face masks on deaths from coronavirus disease 2019 (COVID-19) and all-cause mortality is more sparse and likely to vary by context. Focusing on a quasi-experimental setting in Switzerland, we aimed to determine (i) the effect of face-mask mandates for indoor public spaces on all-cause mortality; and (ii) how the effect has varied over time, and by age and sex.

Methods

Our analysis exploited the fact that between July and October 2020, nine cantons in Switzerland extended a face-mask mandate at different time points from being restricted to public transportation only to applying to all public indoor places. We used both a Difference-in-Differences approach with fixed-effects for canton and week and an event-study approach.

Results

In our main Difference-in-Differences model, the face-mask mandate was associated with a 0.3% reduction in all-cause mortality [95% confidence interval (CI): −3.4% to 2.7%; P = 0.818]. This null effect was confirmed in the event-study approach and a variety of robustness checks. Combining the face-mask mandate with social distancing rules led to an estimated 5.1% (95% CI: −7.9% to −2.4%; P = 0.001) reduction in all-cause mortality.

Conclusions

Mandating face-mask use in public indoor spaces in Switzerland in mid-to-late 2020 does not appear to have resulted in large reductions in all-cause mortality in the short term. There is some suggestion that combining face-mask mandates with social distancing rules reduced all-cause mortality.

Cash transfers as a response to COVID-19: Experimental evidence from Kenya

We deliver one month's average profit to a randomly selected group of female microenterprise owners in Dandora, Kenya, arriving just in advance of an exponential growth in COVID-19 cases. Relative to a control group, firms recoup about one third of their initial decline in profit, and food expenditures increase. Control profit responds to economic conditions and government announcements during our study period, and treatment effects are largest when control profit is at its lowest. PPE spending and precautionary management practices increase to mitigate the health risks of more intensive firm operation, but only among those who perceive COVID-19 as a major risk.

A Clinician's Obligation to be Vaccinated: Four Arguments that Establish a Duty for Healthcare Professionals to be Vaccinated Against COVID-19

This paper defends four lines of argument that establish an ethical obligation for clinicians to be vaccinated against COVID-19. They are:(1) The obligation to protect patients against COVID-19 spread;(2) The obligation to maintain professional competence and remain available for patients;(3) Clinicians' role and place in society in relation to COVID-19;(4) The obligation to encourage societal vaccination uptake.These arguments stand up well against potential objections and provide a compelling case to consider acceptance of COVID-19 vaccination a duty for all clinicians. This duty brings with it the implication that vaccine refusal amounts to a dereliction of the professional's ethical obligations, which means such clinicians should be subject to disciplinary action. Furthermore, this duty provides grounding for mandatory vaccination policies for clinicians.

Development of a COVID-19 risk assessment model for participants at outdoor music festivals: evaluation of the validity and control measure effectiveness based on two actual events in Japan and Spain

We developed an environmental exposure model to estimate the coronavirus disease 2019 (COVID-19) risk among participants at outdoor music festivals and validated the model using two real events-one in Japan (Event 1) and one in Spain (Event 2). Furthermore, we considered a hypothetical situation in which Event 1 was held but enhanced measures were implemented to evaluate the extent to which the risk could be reduced by additional infection control measures, such as negative antigen tests on the day of the event, wearing of masks, disinfection of environmental surfaces, and vaccination. Among 7,392 participants, the total number of already- and newly-infected individuals who participated in Event 1 according to the new model was 47.0 (95% uncertainty interval: 12.5-185.5), which is in good agreement with the reported value (45). The risk of infection at Event 2 (1.98 × 10-2; 95% uncertainty interval: 0.55 × 10-2-6.39 × 10-2), calculated by the model in this study, was also similar to the estimated value in the previous epidemiological study (1.25 × 10-2). These results for the two events in different countries highlighted the validity of the model. Among the additional control measures in the hypothetical Event 1, vaccination, mask-wearing, and disinfection of surfaces were determined to be effective. Based on the combination of all measures, a 94% risk reduction could be achieved. In addition to setting a benchmark for an acceptable number of newly-infected individuals at the time of an event, the application of this model will enable us to determine whether it is necessary to implement additional measures, limit the number of participants, or refrain from holding an event.

Religious leaders can motivate men to cede power and reduce intimate partner violence: Experimental evidence from Uganda

Violence committed by men against women in intimate relationships is a pervasive problem around the world. Patriarchal norms that place men as the head of household are often to blame. Previous research suggests that trusted authorities can shift perceptions of norms and create behavior change. In many settings, a compelling authority on behavior in relationships is religious leaders, who are influential sources of information about proper conduct in relationships and gatekeepers of marriage, but may also uphold traditional gender roles. One way leaders exert their influence is through premarital or couples counseling courses. In this study, we test whether, if given an opportunity to offer a more progressive religious interpretation of gender roles during these courses, religious leaders could motivate men to share power and thereby reduce violence. Building on existing faith networks of Christian religious leaders in western Uganda, we conducted a large pair-matched, randomized controlled trial among 1,680 heterosexual couples in which participants were randomized to attend a 12-session group counseling course or wait-listed. We find that the program shifted power from men to women and reduced intimate partner violence by five percentage points, comparable with more intensive secular programs. These improvements were largest among couples counseled by religious leaders who held the most progressive views at baseline and who critically engaged with the material. Our findings suggest that religious leaders can be effective agents of change for reducing violence.

[Main changes in the «COVID-19 in paediatrics» clinical practice guideline]

We present a summary of the main modifications to the «COVID-19 in Paediatrics» clinical practice guideline made from its initial version, published in 2021, and the version published in 2022. The document was developed following the structured steps of evidence-based medicine and applying the GRADE system to synthesize the evidence, assess its quality and, when appropriate, issue graded recommendations (based on the quality of the evidence, values and preferences, the balance between benefits, risks and costs, equity and feasibility). This update also includes the modifications proposed by external reviewers.We summarised the main modifications in the following sections: epidemiology, clinical features, diagnosis, prevention, treatment and vaccines. In relation to the body of knowledge achieved in the first year of the pandemic, the literature published in the second year contributed additional data, but without substantial modifications in many of the areas. The main changes took place in the field of vaccine research. This update was completed in December 2021, coinciding with the emergence of infections by the omicron variant, so the document will need to be updated in the future.

Main changes in the "COVID-19 in paediatrics" clinical practice guideline

We present a summary of the main modifications to the "COVID-19 in Paediatrics" clinical practice guideline made from its initial version, published in 2021, and the version published in 2022. The document was developed following the structured steps of evidence-based medicine and applying the GRADE system to synthesize the evidence, assess its quality and, when appropriate, issue graded recommendations (based on the quality of the evidence, values and preferences, the balance between benefits, risks and costs, equity and feasibility). This update also includes the modifications proposed by external reviewers. We summarised the main modifications in the following sections: epidemiology, clinical features, diagnosis, prevention, treatment and vaccines. In relation to the body of knowledge achieved in the first year of the pandemic, the literature published in the second year contributed additional data, but without substantial modifications in many the areas. The main changes took place in the field of vaccine research. This update was completed in December 2021, coinciding with the emergence of infections by the omicron variant, so the document will need to be updated in the future.

Knowledge, attitude, and practice towards face mask use among residents of Greater Chennai Corporation, India, March 2021

Background

Wearing a mask is one of the simplest ways to reduce the spread of COVID-19. Studies reported poor mask compliance in Greater Chennai Corporation, India. Hence, we described the knowledge, attitude, and practice regarding mask use among adults (≥18 years) in Greater Chennai Corporation, Tamil Nadu, India.

Methods

We conducted a cross-sectional survey among residents of Greater Chennai Corporation in March 2021. We estimated the sample size to be 203 per strata (slum and non-slum). We used a simple random sampling technique to select 20 locations using a digital map in the slum and non-slum areas. After reaching the location chosen, we selected 10 consecutive households and one adult (≥18 years of age) from each household. We used a validated, semi-structured questionnaire for collecting data regarding knowledge, attitudes, and practices for mask use. We estimated proportions and 95% CI for key variables and compared the variables between slums and non-slums.

Results

Of 430 participants included in the study, 51.4% were males. The mean (S.D.) age of the participants is 41.1 (14.6) years. The majority (86.7%) of the participants felt that wearing a mask helped in reducing the spread of coronavirus and the knowledge differed (p-value < 0.05) between the slum (81.4%) and non-slum (92.3%). Nearly half (46.5%) of the participants did not like being forced to wear the mask. About 63.9% of the participants reported the practice of mask use while going out which was similar across slums and non-slums.

Conclusion

Although the knowledge regarding mask use was good among the public, the attitude was unfavorable. We suggest continuous reinforcement by spreading awareness and educating the community on the appropriate use of the mask.

An epidemic model for SARS-CoV-2 with self-adaptive containment measures

During the COVID-19 pandemic, several countries have resorted to self-adaptive mechanisms that tailor non-pharmaceutical interventions to local epidemiological and health care indicators. These mechanisms reinforce the mutual influence between containment measures and the evolution of the epidemic. To account for such interplay, we develop an epidemiological model that embeds an algorithm mimicking the self-adaptive policy mechanism effective in Italy between November 2020 and March 2022. This extension is key to tracking the historical evolution of health outcomes and restrictions in Italy. Focusing on the epidemic wave that started in mid-2021 after the diffusion of Delta, we compare the functioning of alternative mechanisms to show how the policy framework may affect the trade-off between health outcomes and the restrictiveness of mitigation measures. Mechanisms based on the reproduction number are generally highly responsive to early signs of a surging wave but entail severe restrictions. The emerging trade-off varies considerably depending on specific conditions (e.g., vaccination coverage), with less-reactive mechanisms (e.g., those based on occupancy rates) becoming more appealing in favorable contexts.

Adapt or die: how the pandemic made the shift from EBM to EBM+ more urgent

Evidence-based medicine (EBM's) traditional methods, especially randomised controlled trials (RCTs) and meta-analyses, along with risk-of-bias tools and checklists, have contributed significantly to the science of COVID-19. But these methods and tools were designed primarily to answer simple, focused questions in a stable context where yesterday's research can be mapped more or less unproblematically onto today's clinical and policy questions. They have significant limitations when extended to complex questions about a novel pathogen causing chaos across multiple sectors in a fast-changing global context. Non-pharmaceutical interventions which combine material artefacts, human behaviour, organisational directives, occupational health and safety, and the built environment are a case in point: EBM's experimental, intervention-focused, checklist-driven, effect-size-oriented and deductive approach has sometimes confused rather than informed debate. While RCTs are important, exclusion of other study designs and evidence sources has been particularly problematic in a context where rapid decision making is needed in order to save lives and protect health. It is time to bring in a wider range of evidence and a more pluralist approach to defining what counts as 'high-quality' evidence. We introduce some conceptual tools and quality frameworks from various fields involving what is known as mechanistic research, including complexity science, engineering and the social sciences. We propose that the tools and frameworks of mechanistic evidence, sometimes known as 'EBM+' when combined with traditional EBM, might be used to develop and evaluate the interdisciplinary evidence base needed to take us out of this protracted pandemic. Further articles in this series will apply pluralistic methods to specific research questions.

Community mask wearing as a COVID-19 preventive measure, its barriers, and motivators among rural households of Uganda: A mixed methods approach

Adherence to mask wearing has the potential to reduce coronavirus disease 2019 acquisition risk. However, there is limited information about community mask wearing and its predictors among rural populations. This study aimed to assess the level of adherence to community mask wearing as a COVID-19 prevention measure, its barriers, and motivators among the Ugandan rural population of Wakiso District. This cross-sectional study utilised both quantitative and qualitative data collection methods. The quantitative component employed a semi-structured interviewer-administered questionnaire among 400 participants, to assess the level of adherence and associated predictors towards mask wearing. Modified Poisson regression with robust standard error estimates was used to obtain crude and adjusted prevalence ratios associated with mask wearing. Quantitative data analysis was performed using Stata 15.0 Statistical software. The qualitative component was used to further explore the barriers and motivators of community mask wearing whereseven focus group discussions among 56 community health workers were conducted. Data was analysed using a thematic approach with the help of Nvivo Version 12 software. The quantitative results showed that 70.8% (283/400) of the participants were adherent to mask wearing. Furthermore, reusable (cloth masks) were the most common form of face masks worn by the participants; 71.9% (282/400). Adequate knowledge about mask wearing as a COVID-19 prevention measure was positively associated with mask wearing (adjusted prevalence ratio (95% CI); 3.2 (1.19-8.56)). The qualitative results revealed; sensitization from health workers, provision of free masks, and fear of fines and arrests as motivators to mask wearing. Barriers to mask wearing included: inability to buy masks due to financial constraints, one-time provision of free masks, ill-fitting and worn-out masks, discomfort, and bribery. The practice of community mask wearing was sub-optimal among the study rural communities. Initiatives to scale up the practice need to be feasible for rural communities.

Silver Nanoparticles-Polyethyleneimine-Based Coatings with Antiviral Activity against SARS-CoV-2: A New Method to Functionalize Filtration Media

The use of face masks and air purification systems has been key to curbing the transmission of SARS-CoV-2 aerosols in the context of the current COVID-19 pandemic. However, some masks or air conditioning filtration systems are designed to remove large airborne particles or bacteria from the air, being limited their effectiveness against SARS-CoV-2. Continuous research has been aimed at improving the performance of filter materials through nanotechnology. This article presents a new low-cost method based on electrostatic forces and coordination complex formation to generate antiviral coatings on filter materials using silver nanoparticles and polyethyleneimine. Initially, the AgNPs synthesis procedure was optimized until reaching a particle size of 6.2 ± 2.6 nm, promoting a fast ionic silver release due to its reduced size, obtaining a stable colloid over time and having reduced size polydispersity. The stability of the binding of the AgNPs to the fibers was corroborated using polypropylene, polyester-viscose, and polypropylene-glass spunbond mats as substrates, obtaining very low amounts of detached AgNPs in all cases. Under simulated operational conditions, a material loss less than 1% of nanostructured silver was measured. SEM micrographs demonstrated high silver distribution homogeneity on the polymer fibers. The antiviral coatings were tested against SARS-CoV-2, obtaining inactivation yields greater than 99.9%. We believe our results will be beneficial in the fight against the current COVID-19 pandemic and in controlling other infectious airborne pathogens.

The cross-over of statistical thinking and practices: A pandemic catalyst

Written during the SARS-CoV-2 pandemic, and in recognition of Andy Grieve, the polymath, this article looks at an eclectic mix of topics where statistical thinking and practices should transcend typical dividing lines-with a particular focus on the areas of drug development, public health and social science. The case is made for embedding an experimental (or quasi-experimental) framework within clinical practice for vaccines and treatments following their marketing authorisation. A similar case is made for public health interventions-facilitated by pre-specification of effect size and by the greater use of data standards. A number of recommendations are made whilst noting that progress is being made in some areas.

Modeling the Impact of Nonpharmaceutical Interventions on COVID-19 Transmission in K-12 Schools

Background. The novel coronavirus SARS-CoV-2 spread across the world causing many waves of COVID-19. Children were at high risk of being exposed to the disease because they were not eligible for vaccination during the first 20 mo of the pandemic in the United States. While children 5 y and older are now eligible to receive a COVID-19 vaccine in the United States, vaccination rates remain low despite most schools returning to in-person instruction. Nonpharmaceutical interventions (NPIs) are important for controlling the spread of COVID-19 in K-12 schools. US school districts used varied and layered mitigation strategies during the pandemic. The goal of this article is to analyze the impact of different NPIs on COVID-19 transmission within K-12 schools. Methods. We developed a deterministic stratified SEIR model that captures the role of social contacts between cohorts in disease transmission to estimate COVID-19 incidence under different NPIs including masks, random screening, contact reduction, school closures, and test-to-stay. We designed contact matrices to simulate the contact patterns between students and teachers within schools. We estimated the proportion of susceptible infected associated with each intervention over 1 semester under the Omicron variant. Results. We find that masks and reducing contacts can greatly reduce new infections among students. Weekly screening tests also have a positive impact on disease mitigation. While self-quarantining symptomatic infections and school closures are effective measures for decreasing semester-end infections, they increase absenteeism. Conclusion. The model provides a useful tool for evaluating the impact of a variety of NPIs on disease transmission in K-12 schools. While the model is tested under Omicron variant parameters in US K-12 schools, it can be adapted to study other populations under different disease settings.

Highlights

A stratified SEIR model was developed that captures the role of social contacts in K-12 schools to estimate COVID-19 transmission under different nonpharmaceutical interventions.While masks, random screening, contact reduction, school closures, and test-to-stay are all beneficial interventions, masks and contact reduction resulted in the greatest reduction in new infections among students from the tested scenarios.Layered interventions provide more benefits than implementing interventions independently.

Effect of vaccination on household transmission of SARS-CoV-2 Delta variant of concern

Effective vaccines protect individuals by not only reducing the susceptibility to infection, but also reducing the infectiousness of breakthrough infections in vaccinated cases. To disentangle the vaccine effectiveness against susceptibility to infection (VES) and vaccine effectiveness against infectiousness (VEI), we took advantage of Danish national data comprising 24,693 households with a primary case of SARS-CoV-2 infection (Delta Variant of Concern, 2021) including 53,584 household contacts. In this setting, we estimated VES as 61% (95%-CI: 59-63), when the primary case was unvaccinated, and VEI as 31% (95%-CI: 26-36), when the household contact was unvaccinated. Furthermore, unvaccinated secondary cases with an infection exhibited a three-fold higher viral load compared to fully vaccinated secondary cases with a breakthrough infection. Our results demonstrate that vaccinations reduce susceptibility to infection as well as infectiousness, which should be considered by policy makers when seeking to understand the public health impact of vaccination against transmission of SARS-CoV-2.

Lessons from SARS-CoV-2 in India: A data-driven framework for pandemic resilience

India experienced a massive surge in SARS-CoV-2 infections and deaths during April to June 2021 despite having controlled the epidemic relatively well during 2020. Using counterfactual predictions from epidemiological disease transmission models, we produce evidence in support of how strengthening public health interventions early would have helped control transmission in the country and significantly reduced mortality during the second wave, even without harsh lockdowns. We argue that enhanced surveillance at district, state, and national levels and constant assessment of risk associated with increased transmission are critical for future pandemic responsiveness. Building on our retrospective analysis, we provide a tiered data-driven framework for timely escalation of future interventions as a tool for policy-makers.

Mask wearing in community settings reduces SARS-CoV-2 transmission

The effectiveness of mask wearing at controlling severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has been unclear. While masks are known to substantially reduce disease transmission in healthcare settings [D. K. Chu et al., Lancet 395, 1973–1987 (2020); J. Howard et al., Proc. Natl. Acad. Sci. U.S.A. 118, e2014564118 (2021); Y. Cheng et al., Science eabg6296 (2021)], studies in community settings report inconsistent results [H. M. Ollila et al., medRxiv (2020); J. Brainard et al., Eurosurveillance 25, 2000725 (2020); T. Jefferson et al., Cochrane Database Syst. Rev. 11, CD006207 (2020)]. Most such studies focus on how masks impact transmission, by analyzing how effective government mask mandates are. However, we find that widespread voluntary mask wearing, and other data limitations, make mandate effectiveness a poor proxy for mask-wearing effectiveness. We directly analyze the effect of mask wearing on SARS-CoV-2 transmission, drawing on several datasets covering 92 regions on six continents, including the largest survey of wearing behavior (n= 20 million) [F. Kreuter et al., https://gisumd.github.io/COVID-19-API-Documentation (2020)]. Using a Bayesian hierarchical model, we estimate the effect of mask wearing on transmission, by linking reported wearing levels to reported cases in each region, while adjusting for mobility and nonpharmaceutical interventions (NPIs), such as bans on large gatherings. Our estimates imply that the mean observed level of mask wearing corresponds to a 19% decrease in the reproduction number R. We also assess the robustness of our results in 60 tests spanning 20 sensitivity analyses. In light of these results, policy makers can effectively reduce transmission by intervening to increase mask wearing.

Non-pharmaceutical interventions and mortality in U.S. cities during the great influenza pandemic, 1918-1919

A key issue for the ongoing COVID-19 pandemic is whether non-pharmaceutical public-health interventions (NPIs) retard death rates. Good information about causal effects from NPIs comes from flu-related excess deaths in large U.S. cities during the second wave of the Great Influenza Pandemic, September 1918-February 1919. The measured NPIs are in three categories: school closings, prohibitions of public gatherings, and quarantine/isolation. Although an increase in NPIs flattened the curve in the sense of reducing the ratio of peak to overall flu-related excess death rates, the estimated effect on overall deaths is small and statistically insignificant. These findings differ from those associated with COVID-19 in the sense that facemask mandates and usage seem to reduce COVID-related cases.

Seroprevalence of SARS-CoV-2 infection and associated factors among Bangladeshi slum and non-slum dwellers in pre-COVID-19 vaccination era: October 2020 to February 2021

BACKGROUND

Seroprevalence studies have been carried out in many developed and developing countries to evaluate ongoing and past infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Data on this infection in marginalized populations in urban slums are limited, which may offer crucial information to update prevention and mitigation policies and strategies. We aimed to determine the seroprevalence of SARS-CoV-2 infection and factors associated with seropositivity in slum and non-slum communities in two large cities in Bangladesh.

METHODS

A cross-sectional study was carried out among the target population in Dhaka and Chattogram cities between October 2020 and February 2021. Questionnaire-based data, anthropometric and blood pressure measurements and blood were obtained. SARS-CoV-2 serology was assessed by Roche Elecsys® Anti-SARS-CoV-2 immunoassay.

RESULTS

Among the 3220 participants (2444 adults, ≥18 years; 776 children, 10-17 years), the overall weighted seroprevalence was 67.3% (95% confidence intervals (CI) = 65.2, 69.3) with 71.0% in slum (95% CI = 68.7, 72.2) and 62.2% in non-slum (95% CI = 58.5, 65.8). The weighted seroprevalence was 72.9% in Dhaka and 54.2% in Chattogram. Seroprevalence was positively associated with limited years of formal education (adjusted odds ratio [aOR] = 1.61; 95% CI = 1.43, 1.82), lower income (aOR = 1.23; 95% CI = 1.03, 1.46), overweight (aOR = 1.2835; 95% CI = 1.26, 1.97), diabetes (aOR = 1.67; 95% CI = 1.21, 2.32) and heart disease (aOR = 1.38; 95% CI = 1.03, 1.86). Contrarily, negative associations were found between seropositivity and regular wearing of masks and washing hands, and prior BCG vaccination. About 63% of the population had asymptomatic infection; only 33% slum and 49% non-slum population showed symptomatic infection.

CONCLUSION

The estimated seroprevalence of SARS-CoV-2 was more prominent in impoverished informal settlements than in the adjacent middle-income non-slum areas. Additional factors associated with seropositivity included limited education, low income, overweight and pre-existing chronic conditions. Behavioral factors such as regular wearing of masks and washing hands were associated with lower probability of seropositivity.

Behavioural insights and the evolving COVID-19 pandemic

Behavioural sciences have complemented medical and epidemiological sciences in the response to the SARS-CoV-2 pandemic. As vaccination uptake continues to increase across the EU/EEA - including booster vaccinations - behavioural science research remains important for both pandemic policy, planning of services and communication. From a behavioural perspective, the following three areas are key as the pandemic progresses: (i) attaining and maintaining high levels of vaccination including booster doses across all groups in society, including socially vulnerable populations, (ii) informing sustainable pandemic policies and ensuring adherence to basic prevention measures to protect the most vulnerable population, and (iii) facilitating population preparedness and willingness to support and adhere to the reimposition of restrictions locally or regionally whenever outbreaks may occur. Based on mixed-methods research, expert consultations, and engagement with communities, behavioural data and interventions can thus be important to prevent and effectively respond to local or regional outbreaks, and to minimise socioeconomic and health disparities. In this Perspective, we briefly outline these topics from a European viewpoint, while recognising the importance of considering the specific context in individual countries.

Evaluations of water, sanitation and hygiene interventions should not use diarrhoea as (primary) outcome

Water, sanitation and hygiene interventions have been the subject of cluster trials of unprecedented size, scale and cost in recent years. However, the question 'what works in water, sanitation, hygiene (WASH)?' remains poorly understood. Evaluations of community interventions to prevent infectious disease typically use lab-confirmed infection as a primary outcome; however, WASH trials mostly use reported diarrhoea. While diarrhoea is a significant source of morbidity, it is subjected to significant misclassification error with respect to enteric infection due to the existence of non-infectious diarrhoea and asymptomatic infection. We show how this may lead to bias of estimated effects of interventions from WASH trials towards no effect. The problem is further compounded by other biases in the measurement process. Alongside testing for infection of the gut, an examination of the causal assumptions underlying WASH interventions present several other reliable alternative and complementary measurements and outcomes. Contemporary guidance on the evaluation of complex interventions requires researchers to take a broad view of the causal effects of an intervention across a system. Reported diarrhoea can fail to even be a reliable measure of changes to gastrointestinal health and so should not be used as a primary outcome if we are to progress our knowledge of what works in WASH.

Prioritizing Global Public Health Investments for COVID-19 Response in Real Time: Results from a Delphi Exercise

In the first months of the COVID-19 pandemic, there was a lack of guidance on how to channel the unprecedented amount of health financing toward the pandemic response. We employed a multistep, interactive Delphi process to reach consensus on a “menu” of priority COVID-19 response interventions. In all, 27 health security experts—representing national governments, bilateral and multilateral organizations, academia, technical agencies, and nongovernmental organizations—participated in the exercise. The experts rated 11 technical investment areas and 37 interventions on a 5-point scale in terms of their importance to COVID-19 response. Initial findings were discussed at a virtual meeting where experts suggested modifications. A group of 19 experts then rated a revised list of 11 technical areas and 39 interventions. Consensus was defined as at least 80% of experts agreeing on the importance of a technical area or intervention; stability of scores across the rounds was identified using Wilcoxon matched-pairs and unpaired signed rank tests. Between the initial and final menu, 3 technical areas and 7 interventions were slightly modified, 3 interventions were added, and 1 intervention was removed. Consensus was reached on all 11 technical areas and 35 of the final 39 interventions, and between 34 and 37 interventions were stable across rounds depending on the test used. In this exercise, the health security experts agreed that COVID-19 response financing should prioritize interventions that enhance a country's capacity to test, trace, and treat high-risk populations. Simultaneously, supportive systems (eg, risk communication, community engagement, public health infrastructure, information systems, policy and coordination, workforce capacity, other social protections) should be developed to ensure that nonpharmaceutical and medical interventions can maximize the effectiveness of these systems.

Using high-resolution contact networks to evaluate SARS-CoV-2 transmission and control in large-scale multi-day events

The emergence of highly transmissible SARS-CoV-2 variants has created a need to reassess the risk posed by increasing social contacts as countries resume pre-pandemic activities, particularly in the context of resuming large-scale events over multiple days. To examine how social contacts formed in different activity settings influences interventions required to control Delta variant outbreaks, we collected high-resolution data on contacts among passengers and crew on cruise ships and combined the data with network transmission models. We found passengers had a median of 20 (IQR 10-36) unique close contacts per day, and over 60% of their contact episodes were made in dining or sports areas where mask wearing is typically limited. In simulated outbreaks, we found that vaccination coverage and rapid antigen tests had a larger effect than mask mandates alone, indicating the importance of combined interventions against Delta to reduce event risk in the vaccine era.

Correlation Between Mask Compliance and COVID-19 Outcomes in Europe

Masking was the single most common non-pharmaceutical intervention in the course of the coronavirus disease 2019 (COVID-19) pandemic. Most countries have implemented recommendations or mandates regarding the use of masks in public spaces. The aim of this short study was to analyse the correlation between mask usage against morbidity and mortality rates in the 2020-2021 winter in Europe. Data from 35 European countries on morbidity, mortality, and mask usage during a six-month period were analysed and crossed. Mask usage was more homogeneous in Eastern Europe than in Western European countries. Spearman's correlation coefficients between mask usage and COVID-19 outcomes were either null or positive, depending on the subgroup of countries and type of outcome (cases or deaths). Positive correlations were stronger in Western than in Eastern European countries. These findings indicate that countries with high levels of mask compliance did not perform better than those with low mask usage.

Improving vaccination coverage and offering vaccine to all school-age children allowed uninterrupted in-person schooling in King County, WA: Modeling analysis

The rapid spread of highly transmissible SARS-CoV-2 variants combined with slowing pace of vaccination in Fall 2021 created uncertainty around the future trajectory of the epidemic in King County, Washington, USA. We analyzed the benefits of offering vaccination to children ages 5-11 and expanding the overall vaccination coverage using mathematical modeling. We adapted a mathematical model of SARS-CoV-2 transmission, calibrated to data from King County, Washington, to simulate scenarios of vaccinating children aged 5-11 with different starting dates and different proportions of physical interactions (PPI) in schools being restored. Dynamic social distancing was implemented in response to changes in weekly hospitalizations. Reduction of hospitalizations and estimated time under additional social distancing measures are reported over the 2021-2022 school year. In the scenario with 85% vaccination coverage of 12+ year-olds, offering early vaccination to children aged 5-11 with 75% PPI was predicted to prevent 756 (median, IQR 301-1434) hospitalizations cutting youth hospitalizations in half compared to no vaccination and largely reducing the need for additional social distancing measures over the school year. If, in addition, 90% overall vaccination coverage was reached, 60% of remaining hospitalizations would be averted and the need for increased social distancing would almost certainly be avoided. Our work suggests that uninterrupted in-person schooling in King County was partly possible because reasonable precaution measures were taken at schools to reduce infectious contacts. Rapid vaccination of all school-aged children provides meaningful reduction of the COVID-19 health burden over this school year but only if implemented early. It remains critical to vaccinate as many people as possible to limit the morbidity and mortality associated with future epidemic waves.

Emerging evidence for non-pharmacologic interventions in reducing the burden of respiratory illnesses

The global pandemic caused by SARS-CoV-2 (COVID-19) has led to significant morbidity and mortality, and unprecedented economic and health system disruption. Non-pharmacologic interventions (NPIs) such as masking and physical distancing have formed the underpinnings of COVID-19 infection control strategies. Concomitantly, numerous jurisdictions have seen a decrease in hospitalizations for non-COVID-19 respiratory illnesses (NCRIs) such as asthma, community-acquired pneumonia, influenza, and chronic obstructive pulmonary disease relative to pre-pandemic levels. These associations give rise to a number of testable hypotheses regarding the efficacy of NPIs in reducing the substantial burden of NCRIs. Here, we review emerging perspectives on the role of NPIs in NCRI prevention with the ultimate goal of informing future research and public policy development as we move into what may be the endemic phase of the COVID-19 pandemic.

Nonpharmaceutical interventions to prevent viral respiratory infection in community settings: an umbrella review

Background

Respiratory viruses pose an important public health threat to most communities. Nonpharmaceutical interventions (NPIs) such as masks, hand hygiene or physical distancing, among others, are believed to play an important role in reducing transmission of respiratory viruses. In this umbrella review, we summarise the evidence of the effectiveness of NPIs for the prevention of respiratory virus transmission in the community setting.

Observations

A systematic search of PubMed, Embase, Medline and Cochrane reviews resulted in a total of 24 studies consisting of 11 systematic reviews and meta-analyses, 12 systematic reviews without meta-analyses and one standalone meta-analysis. The current evidence from these data suggests that hand hygiene is protective against respiratory viral infection. The use of hand hygiene and facemasks, facemasks alone and physical distancing were interventions with inconsistent evidence. Interventions such as school closures, oral hygiene or nasal saline rinses were shown to be effective in reducing the risk of influenza; however, the evidence is sparse and mostly of low and critically low quality.

Conclusions

Studies on the effectiveness of NPIs for the prevention of respiratory viral transmission in the community vary in study design, quality and reported effectiveness. Evidence for the use of hand hygiene or facemasks is the strongest; therefore, the most reasonable suggestion is to use hand hygiene and facemasks in the community setting.

The required size of cluster randomized trials of nonpharmaceutical interventions in epidemic settings

To control the SARS‐CoV‐2 pandemic and future pathogen outbreaks requires an understanding of which nonpharmaceutical interventions are effective at reducing transmission. Observational studies, however, are subject to biases that could erroneously suggest an impact on transmission, even when there is no true effect. Cluster randomized trials permit valid hypothesis tests of the effect of interventions on community transmission. While such trials could be completed in a relatively short period of time, they might require large sample sizes to achieve adequate power. However, the sample sizes required for such tests in outbreak settings are largely undeveloped, leaving unanswered the question of whether these designs are practical. We develop approximate sample size formulae and simulation‐based sample size methods for cluster randomized trials in infectious disease outbreaks. We highlight key relationships between characteristics of transmission and the enrolled communities and the required sample sizes, describe settings where trials powered to detect a meaningful true effect size may be feasible, and provide recommendations for investigators in planning such trials. The approximate formulae and simulation banks may be used by investigators to quickly assess the feasibility of a trial, followed by more detailed methods to more precisely size the trial. For example, we show that community‐scale trials requiring 220 clusters with 100 tested individuals per cluster are powered to identify interventions that reduce transmission by 40% in one generation interval, using parameters identified for SARS‐CoV‐2 transmission. For more modest treatment effects, or when transmission is extremely overdispersed, however, much larger sample sizes are required.

Model-Estimated Association Between Simulated US Elementary School-Related SARS-CoV-2 Transmission, Mitigation Interventions, and Vaccine Coverage Across Local Incidence Levels

Importance

With recent surges in COVID-19 incidence and vaccine authorization for children aged 5 to 11 years, elementary schools face decisions about requirements for masking and other mitigation measures. These decisions require explicit determination of community objectives (eg, acceptable risk level for in-school SARS-CoV-2 transmission) and quantitative estimates of the consequences of changing mitigation measures.

Objective

To estimate the association between adding or removing in-school mitigation measures (eg, masks) and COVID-19 outcomes within an elementary school community at varying student vaccination and local incidence rates.

Design, Setting, and Participants

This decision analytic model used an agent-based model to simulate SARS-CoV-2 transmission within a school community, with a simulated population of students, teachers and staff, and their household members (ie, immediate school community). Transmission was evaluated for a range of observed local COVID-19 incidence (0-50 cases per 100 000 residents per day, assuming 33% of all infections detected). The population used in the model reflected the mean size of a US elementary school, including 638 students and 60 educators and staff members in 6 grades with 5 classes per grade.

Exposures

Variant infectiousness (representing wild-type virus, Alpha variant, and Delta variant), mitigation effectiveness (0%-100% reduction in the in-school secondary attack rate, representing increasingly intensive combinations of mitigations including masking and ventilation), and student vaccination levels were varied.

Main Outcomes and Measures

The main outcomes were (1) probability of at least 1 in-school transmission per month and (2) mean increase in total infections per month among the immediate school community associated with a reduction in mitigation; multiple decision thresholds were estimated for objectives associated with each outcome. Sensitivity analyses on adult vaccination uptake, vaccination effectiveness, and testing approaches (for selected scenarios) were conducted.

Results

With student vaccination coverage of 70% or less and moderate assumptions about mitigation effectiveness (eg, masking), mitigation could only be reduced when local case incidence was 14 or fewer cases per 100 000 residents per day to keep the mean additional cases associated with reducing mitigation to 5 or fewer cases per month. To keep the probability of any in-school transmission to less than 50% per month, the local case incidence would have to be 4 or fewer cases per 100 000 residents per day.

Conclusions and Relevance

In this study, in-school mitigation measures (eg, masks) and student vaccinations were associated with substantial reductions in transmissions and infections, but the level of reduction varied across local incidence. These findings underscore the potential role for responsive plans that deploy mitigation strategies based on local COVID-19 incidence, vaccine uptake, and explicit consideration of community objectives.

Evaluating the effectiveness of countywide mask mandates at reducing SARS-CoV-2 infection in the United States

CONTEXT

With the rise of the Delta variant of SARS-CoV-2 and the low vaccination rates in the United States, mitigation strategies to reduce the spread of SARS-CoV-2 are essential for protecting the health of the general public and reducing strain on healthcare facilities. This study compares US counties with and without mask mandates and determines if the mandates are associated with reduced daily COVID-19 infection. US counties have debated whether masks effectively decrease COVID-19 cases, and political pressures have prevented some counties from passing mask mandates. This article investigates the utility of mask mandates in small US counties.

OBJECTIVES

This study aims to analyze the effectiveness of mask mandates in small US counties and places where the population density may not be as high as in larger urban counties and to determine the efficacy of countywide mask mandates in reducing daily COVID-19 infection.

METHODS

The counties studied were those with populations between 40,000 and 105,000 in states that did not have statewide mask mandates. A total of 38 counties were utilized in the study, half with and half without mask mandates. Test counties were followed for 30 days after implementing their mask mandate, and daily new SARS-CoV-2 infection was recorded during this timeframe. The counties were in four randomly selected states that did not have statewide mask mandates. The controls utilized were from counties with similar populations to the test counties and were within the same state as the test county. Controls were followed for the same 30 days as their respective test county. Data were analyzed utilizing t-test and difference-in-difference analyses comparing counties with mask mandates and those without.

RESULTS

These data showed statistically significant lower averages of SARS-CoV-2 daily infection in counties that passed mask mandates when compared with counties that did not. The difference-in-difference analysis revealed a 16.9% reduction in predicted COVID-19 cases at the end of 30 days.

CONCLUSIONS

These data support the effectiveness of mask mandates in reducing SARS-CoV-2 infection spread in small US counties where the population density may be less than in urban counties. Small US counties that are considering passing mask mandates for the population can utilize these data to justify their policy considerations.