SynthesisBMJ open2021
Downsides of face masks and possible mitigation strategies: a systematic review and meta-analysis.
Synthesis in BMJ open, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 47 papers, 8 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
47 citing papers in PubMed, 8 syntheses or guidelines pooled it.
- The filtration performance of fabrics against particles of viral size: a systematic review.BMC infectious diseases · 2026Pooled it
- A systematic review of fit improvement strategies for respirators: lessons learned from the COVID-19 pandemic.BMC public health · 2025Pooled it
- Masks and respirators for prevention of respiratory infections: a state of the science review.Clinical microbiology reviews · 2024Pooled it
- Effectiveness of cloth face masks to prevent viral spread: a meta-analysis.Journal of public health (Oxford, England) · 2024Pooled it
- Child mask mandates for COVID-19: a systematic review.Archives of disease in childhood · 2024Pooled it
- Masking strategy to protect healthcare workers from COVID-19: An umbrella meta-analysis.Infection, disease & health · 2023Pooled it
- Bayesian network meta-analysis of face masks' impact on human physiology.Scientific reports · 2022Pooled it
- How efficient are facial masks against COVID-19? Evaluating the mask use of various communities one year into the pandemicTurkish journal of medical sciences · 2021Pooled it
- Effect of face masks on dyspnea perception, cardiopulmonary parameters, and facial temperature in healthy adults.Narra J · 2024Trial
- Effects of face coverings on people and interactions in mental health settings: scoping review.BJPsych open · 2025Review
- Assessment of the Psychometric Properties of the Mask Usability Scale: A Measure of the Perceived Usability of N95 Respirators Among Healthcare Students and Staff.Journal of advanced nursing · 2025Article
- Assessing the impact of different types of masks on COPD patients: a randomised controlled trial.ERJ open research · 2025Article
- Knowledge, attitudes and practices related to SARS-CoV-2 prevention in Kenya.Journal of public health in Africa · 2025Article
- The impacts of mask-wearing regulations on stroke morbidity and mortality: a population-based retrospective cohort study in China.BMC public health · 2024Article
- Consistent FFP2-masking as part of reducing viral respiratory infections on medical wards for allogeneic hematopoietic stem cell transplantation.Scientific reports · 2024Article
- Please wear a mask: a systematic case for mask wearing mandates.Journal of medical ethics · 2024Article
- Assessing the impact of diverse mask types on COPD patients: a randomised controlled trial study protocol.BMJ open · 2024Article
- Evolution of WHO COVID-19 mask guidelines amid intense demands for rapid advice.PLOS global public health · 2024Article
- One year of COVID-19 in dental health services in Norway: psychological impact, risk perceptions and vaccination status.BMC health services research · 2023Article
- Psychological and psychosocial determinants of COVID Health Related Behaviours (COHeRe): An evidence and gap map.Campbell systematic reviews · 2023Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo identify, appraise and synthesise studies evaluating the downsides of wearing face masks in any setting. We also discuss potential strategies to mitigate these downsides.
designSystematic review and meta-analysis. DATA SOURCES: PubMed, Embase, CENTRAL and EuropePMC were searched (inception-18 May 2020), and clinical registries were searched via CENTRAL. We also did a forward-backward citation search of the included studies. INCLUSION CRITERIA: We included randomised controlled trials and observational studies comparing face mask use to any active intervention or to control. DATA EXTRACTION AND ANALYSIS: Two author pairs independently screened articles for inclusion, extracted data and assessed the quality of included studies. The primary outcomes were compliance, discomforts, harms and adverse events of wearing face masks.
resultsWe screened 5471 articles, including 37 (40 references); 11 were meta-analysed. For mask wear adherence, 47% (95% CI 25% to 68%, p<0.0001), more people wore face masks in the face mask group compared with control; adherence was significantly higher (26%, 95% CI 8% to 46%, p<0.01) in the surgical/medical mask group than in N95/P2 group. The largest number of studies reported on the discomfort and irritation outcome (20 studies); fewest reported on the misuse of masks, and none reported on mask contamination or risk compensation behaviour. Risk of bias was generally high for blinding of participants and personnel and low for attrition and reporting biases.
conclusionsThere are insufficient data to quantify all of the adverse effects that might reduce the acceptability, adherence and effectiveness of face masks. New research on face masks should assess and report the harms and downsides. Urgent research is also needed on methods and designs to mitigate the downsides of face mask wearing, particularly the assessment of possible alternatives. SYSTEMATIC REVIEW REGISTRATION: Open Science Framework website https://osf.io/sa6kf/ (timestamp 20-05-2020).
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Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.