https://publichealth.jmir.org/issue/feedJMIR Public Health and Surveillance2023-01-05T10:15:03-05:00JMIR Publicationseditor@jmir.orgOpen Journal Systems Unless stated otherwise, all articles are open-access distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work ("first published in the Journal of Medical Internet Research...") is properly cited with original URL and bibliographic citation information. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included. Innovations in Public Health practice and research https://publichealth.jmir.org/2024/1/e46591/ Association Between Long‑Term Exposure to Air Pollution and the Rate of Mortality After Hip Fracture Surgery in Patients Older Than 60 Years: Nationwide Cohort Study in Taiwan2024-03-18T11:30:04-04:00Shu-Han ChuangYi-Jie KuoShu-Wei HuangHan-Wei ZhangHsiao-Ching PengYu-Pin Chen<strong>Background:</strong> To enhance postoperative patient survival, particularly in older adults, understanding the predictors of mortality following hip fracture becomes paramount. Air pollution, a prominent global environmental issue, has been linked to heightened morbidity and mortality across a spectrum of diseases. Nevertheless, the precise impact of air pollution on hip fracture outcomes remains elusive. <strong>Objective:</strong> This retrospective study aims to comprehensively investigate the profound influence of a decade-long exposure to 12 diverse air pollutants on the risk of post–hip fracture mortality among older Taiwanese patients (older than 60 years). We hypothesized that enduring long-term exposure to air pollution would significantly elevate the 1-year mortality rate following hip fracture surgery. <strong>Methods:</strong> From Taiwan’s National Health Insurance Research Database, we obtained the data of patients who underwent hip fracture surgery between July 1, 2003, and December 31, 2013. Using patients’ insurance registration data, we estimated their cumulative exposure levels to sulfur dioxide (SO<sub>2</sub>), carbon dioxide (CO<sub>2</sub>), carbon monoxide (CO), ozone (O<sub>3</sub>), particulate matter having a size of <10 μm (PM<sub>10</sub>), particulate matter having a size of <2.5 μm (PM<sub>2.5</sub>), nitrogen oxides (NO<sub>X</sub>), nitrogen monoxide (NO), nitrogen dioxide (NO<sub>2</sub>), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), and methane (CH<sub>4</sub>). We quantified the dose-response relationship between these air pollutants and the risk of mortality by calculating hazard ratios associated with a 1 SD increase in exposure levels over a decade. <strong>Results:</strong> Long-term exposure to SO<sub>2</sub>, CO, PM<sub>10</sub>, PM<sub>2.5</sub>, NO<sub>X</sub>, NO, NO<sub>2</sub>, THC, NMHC, and CH<sub>4</sub> demonstrated significant associations with heightened all-cause mortality risk within 1 year post hip fracture surgery among older adults. For older adults, each 1 SD increment in the average exposure levels of SO<sub>2</sub>, CO, PM<sub>10</sub>, PM<sub>2.5</sub>, NO<sub>X</sub>, NO, NO<sub>2</sub>, THC, NMHC, and CH<sub>4</sub> corresponded to a substantial escalation in mortality risk, with increments of 14%, 49%, 18%, 12%, 41%, 33%, 38%, 20%, 9%, and 26%, respectively. We further noted a 35% reduction in the hazard ratio for O<sub>3</sub> exposure suggesting a potential protective effect, along with a trend of potentially protective effects of CO<sub>2</sub>. <strong>Conclusions:</strong> This comprehensive nationwide retrospective study, grounded in a population-based approach, demonstrated that long-term exposure to specific air pollutants significantly increased the risk of all-cause mortality within 1 year after hip fracture surgery in older Taiwanese adults. A reduction in the levels of SO<sub>2</sub>, CO, PM<sub>10</sub>, PM<sub>2.5</sub>, NO<sub>X</sub>, NO, NO<sub>2</sub>, THC, NMHC, and CH<sub>4</sub> may reduce the risk of mortality after hip fracture surgery. This study provides robust evidence and highlights the substantial impact of air pollution on the outcomes of hip fractures. 2024-03-18T11:30:04-04:00 https://publichealth.jmir.org/2024/1/e53040/ Investigating Nonspecific Effects of the Live-Attenuated Japanese Encephalitis Vaccine on Lower Respiratory Tract Infections in Children Aged 25-35 Months: Retrospective Cohort Study2024-03-18T10:30:24-04:00Siyi ZhanHongbo LinYingying YangTao ChenSheng MaoChuanxi Fu<strong>Background:</strong> Live attenuated vaccines may be used to prevent nontargeted diseases such as lower respiratory tract infections (LRTIs) due to their nonspecific effects (NSEs). <strong>Objective:</strong> We aimed to analyze the NSEs of the Japanese encephalitis vaccine on pediatric LRTIs in children aged 25 months to 35 months. <strong>Methods:</strong> A retrospective cohort study was conducted by using a population-based electronic health record database in Zhejiang, China. Enrolled participants were children born from January 1, 2017, to December 31, 2017, and who were inoculated with the live-attenuated Japanese encephalitis vaccine (JE-L) or inactivated Japanese encephalitis vaccine (JE-I) as the most recent vaccine at 24 months of age. The study was carried out between January 1, 2019, and December 31, 2019. All inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months were recorded. The Andersen-Gill model was used to assess the NSEs of JE-L against LRTIs in children and compared with those of JE-I as the most recent vaccine. <strong>Results:</strong> A total of 810 children born in 2017 were enrolled, of whom 585 received JE-L (JE-L cohort) and 225 received JE-I (JE-I cohort) as their last vaccine. The JE-L cohort showed a reduced risk of LRTIs (adjusted hazard ratio [aHR] 0.537, 95% CI 0.416-0.693), including pneumonia (aHR 0.501, 95% CI 0.393-0.638) and acute bronchitis (aHR 0.525, 95% CI 0.396-0.698) at 25 months to 35 months of age. The NSEs provided by JE-L were especially pronounced in female children (aHR 0.305, 95% CI 0.198-0.469) and children without chronic diseases (aHR 0.553, 95% CI 0.420-0.729), without siblings (aHR 0.361, 95% CI 0.255-0.511), with more than 30 inpatient and outpatient hospital visits prior to 24 months of age (aHR 0.163, 95% CI 0.091-0.290), or with 5 to 10 inpatient and outpatient hospital visits due to infectious diseases prior to 24 months old (aHR 0.058, 95% CI 0.017-0.202). <strong>Conclusions:</strong> Compared with JE-I, receiving JE-L as the most recent vaccine was associated with lower risk of inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months. The nature of NSEs induced by JE-L should be considered for policymakers and physicians when recommending JE vaccines to those at high risk of infection from the Japanese encephalitis virus. 2024-03-18T10:30:24-04:00 https://publichealth.jmir.org/2024/1/e49772/ Association Between Physical Activity and the Risk of Burnout in Health Care Workers: Systematic Review2024-03-18T10:15:22-04:00Pierpaolo MincaroneAntonella BodiniMaria Rosaria TumoloSaverio SabinaRiccardo ColellaLinda ManniniEugenio SabatoCarlo Giacomo Leo<strong>Background:</strong> Burnout is a multidimensional psychological syndrome that arises from chronic workplace stress. Health care workers (HCWs), who operate in physically and emotionally exhausting work contexts, constitute a vulnerable group. This, coupled with its subsequent impact on patients and public economic resources, makes burnout a significant public health concern. Various self-care practices have been suggested to have a positive effect on burnout among HCWs. Of these, physical activity stands out for its ability to combine psychological, physiological, and biochemical mechanisms. In fact, it promotes psychological detachment from work and increases self-efficacy by inhibiting neurotransmitters and neuromodulators, increasing endorphin levels, enhancing mitochondrial function, and attenuating the hypothalamic pituitary-adrenal axis response to stress. <strong>Objective:</strong> Our objective was to conduct a systematic review of the evidence on the association between physical activity and burnout among HCWs. <strong>Methods:</strong> We considered HCWs, physical activity, and burnout, framing them as population, exposure, and outcome, respectively. We searched APA PsycArticles, MEDLINE, and Scopus until July 2022. We extracted relevant data on study design, methods to measure exposure and outcome, and statistical approaches. <strong>Results:</strong> Our analysis encompassed 21 independent studies. Although 10% (2/21) of the studies explicitly focused on physical activity, the remaining investigations were exploratory in nature and examined various predictors, including physical activity. The most commonly used questionnaire was the Maslach Burnout Inventory. Owing to the heterogeneity in definitions and cutoffs used, the reported prevalence of burnout varied widely, ranging from 7% to 83%. Heterogeneity was also observed in the measurement tools used to assess physical activity, with objective measures rarely used. In total, 14% (3/21) of the studies used structured questionnaires to assess different types of exercise, whereas most studies (18/21, 86%) only recorded the attainment of a benchmark or reported the frequency, intensity, or duration of exercise. The reported prevalence of physically active HCWs ranged from 44% to 87%. The analyses, through a variety of inferential approaches, indicated that physical activity is often associated with a reduced risk of burnout, particularly in the domains of emotional exhaustion and depersonalization. Furthermore, we compiled and classified a list of factors associated with burnout. <strong>Conclusions:</strong> Our comprehensive overview of studies investigating the association between physical activity and burnout in HCWs revealed significant heterogeneity in definitions, measurements, and analyses adopted in the literature. To address this issue, it is crucial to adopt a clear definition of physical activity and make thoughtful choices regarding measurement tools and methodologies for data analysis. Our considerations regarding the measurement of burnout and the comprehensive list of associated factors have the potential to improve future studies aimed at informing decision-makers, thus laying the foundation for more effective management measures to address burnout. 2024-03-18T10:15:22-04:00 https://publichealth.jmir.org/2024/1/e47979/ Predicting COVID-19 Vaccination Uptake Using a Small and Interpretable Set of Judgment and Demographic Variables: Cross-Sectional Cognitive Science Study2024-03-18T10:00:05-04:00Nicole L VikeSumra BariLeandros StefanopoulosShamal LalvaniByoung Woo KimNicos MaglaverasMartin BlockHans C BreiterAggelos K Katsaggelos<strong>Background:</strong> Despite COVID-19 vaccine mandates, many chose to forgo vaccination, raising questions about the psychology underlying how judgment affects these choices. Research shows that reward and aversion judgments are important for vaccination choice; however, no studies have integrated such cognitive science with machine learning to predict COVID-19 <i>vaccine uptake</i>. <strong>Objective:</strong> This study aims to determine the predictive power of a small but interpretable set of judgment variables using 3 machine learning algorithms to predict COVID-19 <i>vaccine uptake</i> and interpret what profile of judgment variables was important for prediction. <strong>Methods:</strong> We surveyed 3476 adults across the United States in December 2021. Participants answered demographic, COVID-19 <i>vaccine uptake</i> (ie, whether participants were fully vaccinated), and COVID-19 precaution questions. Participants also completed a picture-rating task using images from the International Affective Picture System. Images were rated on a Likert-type scale to calibrate the degree of liking and disliking. Ratings were computationally modeled using relative preference theory to produce a set of graphs for each participant (minimum <i>R</i><sup>2</sup>>0.8). In total, 15 judgment features were extracted from these graphs, 2 being analogous to risk and loss aversion from behavioral economics. These judgment variables, along with demographics, were compared between those who were fully vaccinated and those who were not. In total, 3 machine learning approaches (random forest, balanced random forest [BRF], and logistic regression) were used to test how well judgment, demographic, and COVID-19 precaution variables predicted <i>vaccine uptake</i>. Mediation and moderation were implemented to assess statistical mechanisms underlying successful prediction. <strong>Results:</strong> Age, income, marital status, employment status, ethnicity, educational level, and sex differed by <i>vaccine uptake</i> (Wilcoxon rank sum and chi-square <i>P</i><.001). Most judgment variables also differed by <i>vaccine uptake</i> (Wilcoxon rank sum <i>P</i><.05). A similar area under the receiver operating characteristic curve (AUROC) was achieved by the 3 machine learning frameworks, although random forest and logistic regression produced specificities between 30% and 38% (vs 74.2% for BRF), indicating a lower performance in predicting unvaccinated participants. BRF achieved high precision (87.8%) and AUROC (79%) with moderate to high accuracy (70.8%) and balanced recall (69.6%) and specificity (74.2%). It should be noted that, for BRF, the negative predictive value was <50% despite good specificity. For BRF and random forest, 63% to 75% of the feature importance came from the 15 judgment variables. Furthermore, age, income, and educational level mediated relationships between judgment variables and <i>vaccine uptake</i>. <strong>Conclusions:</strong> The findings demonstrate the underlying importance of judgment variables for vaccine choice and uptake, suggesting that vaccine education and messaging might target varying judgment profiles to improve uptake. These methods could also be used to aid vaccine rollouts and health care preparedness by providing location-specific details (eg, identifying areas that may experience low vaccination and high hospitalization). 2024-03-18T10:00:05-04:00 https://publichealth.jmir.org/2024/1/e50743/ Estimation of the Population Size of Street- and Venue-Based Female Sex Workers and Sexually Exploited Minors in Rwanda in 2022: 3-Source Capture-Recapture2024-03-15T10:45:25-04:00Elysee TuyishimeEric RemeraCatherine KayitesiSamuel MalambaBeata SangwayireIgnace Habimana KabanoHoracio Ruisenor-EscuderoTom OluochAngela Unna Chukwu<strong>Background:</strong> HIV surveillance among key populations is a priority in all epidemic settings. Female sex workers (FSWs) globally as well as in Rwanda are disproportionately affected by the HIV epidemic; hence, the Rwanda HIV and AIDS National Strategic Plan (2018-2024) has adopted regular surveillance of population size estimation (PSE) of FSWs every 2-3 years. <strong>Objective:</strong> We aimed at estimating, for the fourth time, the population size of street- and venue-based FSWs and sexually exploited minors aged ≥15 years in Rwanda. <strong>Methods:</strong> In August 2022, the 3-source capture-recapture method was used to estimate the population size of FSWs and sexually exploited minors in Rwanda. The field work took 3 weeks to complete, with each capture occasion lasting for a week. The sample size for each capture was calculated using shinyrecap with inputs drawn from previously conducted estimation exercises. In each capture round, a stratified multistage sampling process was used, with administrative provinces as strata and FSW hotspots as the primary sampling unit. Different unique objects were distributed to FSWs in each capture round; acceptance of the unique object was marked as successful capture. Sampled FSWs for the subsequent capture occasions were asked if they had received the previously distributed unique object in order to determine recaptures. Statistical analysis was performed in R (version 4.0.5), and Bayesian Model Averaging was performed to produce the final PSE with a 95% credibility set (CS). <strong>Results:</strong> We sampled 1766, 1848, and 1865 FSWs and sexually exploited minors in each capture round. There were 169 recaptures strictly between captures 1 and 2, 210 recaptures exclusively between captures 2 and 3, and 65 recaptures between captures 1 and 3 only. In all 3 captures, 61 FSWs were captured. The median PSE of street- and venue-based FSWs and sexually exploited minors in Rwanda was 37,647 (95% CS 31,873-43,354), corresponding to 1.1% (95% CI 0.9%-1.3%) of the total adult females in the general population. Relative to the adult females in the general population, the western and northern provinces ranked first and second with a higher concentration of FSWs, respectively. The cities of Kigali and eastern province ranked third and fourth, respectively. The southern province was identified as having a low concentration of FSWs. <strong>Conclusions:</strong> We provide, for the first time, both the national and provincial level population size estimate of street- and venue-based FSWs in Rwanda. Compared with the previous 2 rounds of FSW PSEs at the national level, we observed differences in the street- and venue-based FSW population size in Rwanda. Our study might not have considered FSWs who do not want anyone to know they are FSWs due to several reasons, leading to a possible underestimation of the true PSE. 2024-03-15T10:45:25-04:00 https://publichealth.jmir.org/2024/1/e52093/ Using EpiCore to Enable Rapid Verification of Potential Health Threats: Illustrated Use Cases and Summary Statistics2024-03-15T10:30:25-04:00Nomita DiviJaś ManteroMarlo LibelOnicio Leal NetoMarinanicole SchultheissKara SewalkJohn BrownsteinMark Smolinski<strong>Background:</strong> The proliferation of digital disease-detection systems has led to an increase in earlier warning signals, which subsequently have resulted in swifter responses to emerging threats. Such highly sensitive systems can also produce weak signals needing additional information for action. The delays in the response to a genuine health threat are often due to the time it takes to verify a health event. It was the delay in outbreak verification that was the main impetus for creating EpiCore. <strong>Objective:</strong> This paper describes the potential of crowdsourcing information through EpiCore, a network of voluntary human, animal, and environmental health professionals supporting the verification of early warning signals of potential outbreaks and informing risk assessments by monitoring ongoing threats. <strong>Methods:</strong> This paper uses summary statistics to assess whether EpiCore is meeting its goal to accelerate the time to verification of identified potential health events for epidemic and pandemic intelligence purposes from around the world. Data from the EpiCore platform from January 2018 to December 2022 were analyzed to capture request for information response rates and verification rates. Illustrated use cases are provided to describe how EpiCore members provide information to facilitate the verification of early warning signals of potential outbreaks and for the monitoring and risk assessment of ongoing threats through EpiCore and its utilities. <strong>Results:</strong> Since its launch in 2016, EpiCore network membership grew to over 3300 individuals during the first 2 years, consisting of professionals in human, animal, and environmental health, spanning 161 countries. The overall EpiCore response rate to requests for information increased by year between 2018 and 2022 from 65.4% to 68.8% with an initial response typically received within 24 hours (in 2022, 94% of responded requests received a first contribution within 24 h). Five illustrated use cases highlight the various uses of EpiCore. <strong>Conclusions:</strong> As the global demand for data to facilitate disease prevention and control continues to grow, it will be crucial for traditional and nontraditional methods of disease surveillance to work together to ensure health threats are captured earlier. EpiCore is an innovative approach that can support health authorities in decision-making when used complementarily with official early detection and verification systems. EpiCore can shorten the time to verification by confirming early detection signals, informing risk-assessment activities, and monitoring ongoing events. 2024-03-15T10:30:25-04:00 https://publichealth.jmir.org/2024/1/e55327/ Temporal Trends of Asthma Among Children in the Western Pacific Region From 1990 to 2045: Longitudinal Observational Study2024-03-14T10:30:04-04:00Cheng-hao YangXin-yu LiJia-jie LvMeng-jie HouRu-hong ZhangHong GuoChu Feng<strong>Background:</strong> Asthma has become one of the most common chronic conditions worldwide, especially among children. Recent findings show that the prevalence of childhood asthma has increased by 12.6% over the past 30 years, with >262 million people currently affected globally. The reasons for the growing asthma epidemic remain complex and multifactorial. <strong>Objective:</strong> This study aims to provide an up-to-date analysis of the changing global and regional asthma prevalence, mortality, disability, and risk factors among children aged <20 years by leveraging the latest data from the Global Burden of Disease Study 2019. Findings from this study can help inform priority areas for intervention to alleviate the rising burden of childhood asthma globally. <strong>Methods:</strong> The study used data from the Global Burden of Disease Study 2019, concentrating on children aged 0 to 14 years with asthma. We conducted an in-depth analysis of asthma, including its age-standardized prevalence, incidence, mortality, and disability-adjusted life years (DALYs), across diverse demographics, such as region, age, sex, and sociodemographic index, spanning 1990 to 2019. We also projected the future burden of the disease. <strong>Results:</strong> Overall, in the Western Pacific Region, the age-standardized prevalence rate of asthma among children increased slightly, from 3898.4 cases per 100,000 people in 1990 to 3924 per 100,000 in 2019. The age-standardized incidence rate of asthma also increased slightly, from 979.2 to 994.9 per 100,000. In contrast, the age-standardized death rate of asthma decreased from 0.9 to 0.4 per 100,000 and the age-standardized DALY rate decreased from 234.9 to 189.7 per 100,000. At the country level, Japan experienced a considerable decrease in the age-standardized prevalence rate of asthma among children, from 6669.1 per 100,000 in 1990 to 5071.5 per 100,000 in 2019. Regarding DALYs, Japan exhibited a notable reduction, from 300.6 to 207.6 per 100,000. Malaysia also experienced a DALY rate reduction, from 188.4 to 163.3 per 100,000 between 1990 and 2019. We project that the burden of disease in countries other than Japan and the Philippines will remain relatively stable up to 2045. <strong>Conclusions:</strong> The study indicates an increase in the prevalence and incidence of pediatric asthma, coupled with a decrease in mortality and DALYs in the Western Pacific Region between 1990 and 2019. These intricate phenomena appear to result from a combination of lifestyle shifts, environmental influences, and barriers to health care access. The findings highlight that nations such as Japan have achieved notable success in managing asthma. Overall, the study identified areas of improvement in view of persistent disease burden, underscoring the need for comprehensive collaborative efforts to mitigate the impact of pediatric asthma throughout the region. 2024-03-14T10:30:04-04:00 https://publichealth.jmir.org/2024/1/e54756/ Authors’ Reply: “The Need for a Bleed Type–Specific Annual Bleeding Rate in Hemophilia Studies”2024-03-13T13:00:18-04:00Limin WangShimeng LiuShan JiangChaofan LiLiyong LuYunhai FangShunping Li2024-03-13T13:00:18-04:00 https://publichealth.jmir.org/2024/1/e51372/ The Need for a Bleed Type–Specific Annual Bleeding Rate in Hemophilia Studies2024-03-13T13:00:04-04:00Kun Huang2024-03-13T13:00:04-04:00 https://publichealth.jmir.org/2024/1/e49307/ Effects of Face Mask Mandates on COVID-19 Transmission in 51 Countries: Retrospective Event Study2024-03-08T10:15:23-05:00Anatol-Fiete NäherMatthias Schulte-AlthoffMarvin KopkaFelix BalzerFrancisco Pozo-Martin<strong>Background:</strong> The question of the utility of face masks in preventing acute respiratory infections has received renewed attention during the COVID-19 pandemic. However, given the inconclusive evidence from existing randomized controlled trials, evidence based on real-world data with high external validity is missing. <strong>Objective:</strong> To add real-world evidence, this study aims to examine whether mask mandates in 51 countries and mask recommendations in 10 countries increased self-reported face mask use and reduced SARS-CoV-2 reproduction numbers and COVID-19 case growth rates. <strong>Methods:</strong> We applied an event study approach to data pooled from four sources: (1) country-level information on self-reported mask use was obtained from the COVID-19 Trends and Impact Survey, (2) data from the Oxford COVID-19 Government Response Tracker provided information on face mask mandates and recommendations and any other nonpharmacological interventions implemented, (3) mobility indicators from Google’s Community Mobility Reports were also included, and (4) SARS-CoV-2 reproduction numbers and COVID-19 case growth rates were retrieved from the Our World in Data—COVID-19 data set. <strong>Results:</strong> Mandates increased mask use by 8.81 percentage points (<i>P</i>=.006) on average, and SARS-CoV-2 reproduction numbers declined on average by −0.31 units (<i>P</i>=.008). Although no significant average effect of mask mandates was observed for growth rates of COVID-19 cases (−0.98 percentage points; <i>P</i>=.56), the results indicate incremental effects on days 26 (−1.76 percentage points; <i>P</i>=.04), 27 (−1.89 percentage points; <i>P</i>=.05), 29 (−1.78 percentage points; <i>P</i>=.04), and 30 (−2.14 percentage points; <i>P</i>=.02) after mandate implementation. For self-reported face mask use and reproduction numbers, incremental effects are seen 6 and 13 days after mandate implementation. Both incremental effects persist for >30 days. Furthermore, mask recommendations increased self-reported mask use on average (5.84 percentage points; <i>P</i><.001). However, there were no effects of recommendations on SARS-CoV-2 reproduction numbers or COVID-19 case growth rates (−0.06 units; <i>P</i>=.70 and −2.45 percentage points; <i>P</i>=.59). Single incremental effects on self-reported mask use were observed on days 11 (3.96 percentage points; <i>P</i>=.04), 13 (3.77 percentage points; <i>P</i>=.04) and 25 to 27 (4.20 percentage points; <i>P</i>=.048 and 5.91 percentage points; <i>P</i>=.01) after recommendation. Recommendations also affected reproduction numbers on days 0 (−0.07 units; <i>P</i>=.03) and 1 (−0.07 units; <i>P</i>=.03) and between days 21 (−0.09 units; <i>P</i>=.04) and 28 (−0.11 units; <i>P</i>=.05) and case growth rates between days 1 and 4 (−1.60 percentage points; <i>P</i>=.03 and −2.19 percentage points; <i>P</i>=.03) and on day 23 (−2.83 percentage points; <i>P</i>=.05) after publication. <strong>Conclusions:</strong> Contrary to recommendations, mask mandates can be used as an effective measure to reduce SARS-CoV-2 reproduction numbers. However, mandates alone are not sufficient to reduce growth rates of COVID-19 cases. Our study adds external validity to the existing randomized controlled trials on the effectiveness of face masks to reduce the spread of SARS-CoV-2. 2024-03-08T10:15:23-05:00