Effectiveness of using face masks and personal protective equipment to reducing the spread of COVID-19: A systematic review and meta-analysis of case–control studies


Department of Biostatistics and Epidemiology, Faculty of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran


Recently published researches show that 59% of all transmission came from asymptomatic transmission and at the time of diagnosis health-care workers (HCWs) tend to present without respiratory symptoms. These evidences have raised questions on whether an essential policy for use of personal protective equipment (PPE) is the best approach in HCW and other people or not. Therefore, this study conducted to investigate the effectiveness of using face masks and PPE in reducing the spread of COVID-19 in health-care and non-health-care settings. This systematic review and meta-analysis study was prepared according to the preferred reporting items for systematic review and meta-analysis statement and guided by meta-analysis of observational studies recommendations. Searches in databases were conducted from December 2019 to July 2021. Random-effects meta-analysis was performed to investigate the effect of using face masks and PPE on spread of COVID-19. Heterogeneity among studies was assessed using Cochran's Q test and the I2 metrics. In total, 9920 individuals from 14 studies were included in this study. In all settings, application of PPE or any type of masks was associated with reduction in risk of COVID-19 (odds ratio [OR] = 0.44; 95% confidence interval [CI]: [0.29, 0.65]; I2 = 85.21%). In the HCW subgroup, the protective effect had a combined OR of 0.33 (95% CI: (0.15,0.73), I2 = 82.61%). Six studies were found protective effects of wearing mask in non-HCWs (OR = 0.58, 95% CI: (0.31, 1.06), I2 = 85.63%). Results suggest that there is association between face mask/PPE use and reduction of COVID-19.


Biagi A, Rossi L, Malagoli A, Zanni A, Sticozzi C, Comastri G, et al. Clinical and epidemiological characteristics of 320 deceased patients with COVID-19 in an Italian Province: A retrospective observational study. J Med Virol 2020;92:2718-24.  Back to cited text no. 1
Wang K, Zuo P, Liu Y, Zhang M, Zhao X, Xie S, et al. Clinical and laboratory predictors of in-hospital mortality in patients with coronavirus disease-2019: A cohort study in Wuhan, China. Clin Infect Dis 2020;71:2079-88.  Back to cited text no. 2
World Health Organization. Advice on the Use of Masks in the Context of COVID-19; April, 2020. Available from: https://www.who.int/publications-detail/advice-on-the-use-of-masks-in-thecommunity-during-home-care-and-in-healthcare-settings-in-thecontext- of-the-novel-coronavirus-(2019-ncov)-outbreak. [Last accessed on 2020 May 26].  Back to cited text no. 3
World Health Organization. Modes of Transmission of Virus Causing COVID-19: Implications for IPC Precaution Recommendations. Scientific Brief WHO/2019 nCoV/Sci_Brief/Transmission_modes/2020. Available from: https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipcprecaution-recommendationsWorldHealthOrganization. [Last accessed on 2020 May 26; Last updated on 2020 Mar 29].  Back to cited text no. 4
Chen J. Pathogenicity and transmissibility of 2019-nCoV-A quick overview and comparison with other emerging viruses. Microbes Infect 2020;22:69-71.  Back to cited text no. 5
Williamson EJ, Walker AJ, Bhaskaran K, Bacon S, Bates C, Morton CE, et al. Factors associated with COVID-19-related death using OpenSAFELY. Nature 2020;584:430-6.  Back to cited text no. 6
Giacomelli A, Ridolfo AL, Milazzo L, Oreni L, Bernacchia D, Siano M, et al. 30-day mortality in patients hospitalized with COVID-19 during the first wave of the Italian epidemic: A prospective cohort study. Pharmacol Res 2020;158:104931.  Back to cited text no. 7
COVID-19 Coronavirus Pandemic. Available from: https://www.worldometers.info/coronavirus/. [Last updated on 2021 Aug 11, 09:55 GMT].  Back to cited text no. 8
Clark A, Jit M, Warren-Gash C, Guthrie B, Wang HH, Mercer SW, et al. Global, regional, and national estimates of the population at increased risk of severe COVID-19 due to underlying health conditions in 2020: A modelling study. Lancet Glob Health 2020;8:e1003-17.  Back to cited text no. 9
Gan Y, Ma J, Wu J, Chen Y, Zhu H, Hall B. Immediate and delayed psychological effects of province-wide lockdown and personal quarantine during the COVID-19 outbreak in China. Psychological Med 2022;52:1321-32.  Back to cited text no. 10
World Health Organization (WHO). Coronavirus Disease (COVID-19) Advice for the Public 2020; 2021. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public. [Last accessed on 2021 Apr 15].  Back to cited text no. 11
Mendoza-Jiménez MJ, Hannemann TV, Atzendorf J. Behavioral risk factors and adherence to preventive measures: Evidence from the early stages of the COVID-19 pandemic. Front Public Health 2021;9:674597.  Back to cited text no. 12
Atnafie SA, Anteneh DA, Yimenu DK, Kifle ZD. Assessment of exposure risks to COVID-19 among frontline health care workers in Amhara Region, Ethiopia: A cross-sectional survey. PLoS One 2021;16:e0251000.  Back to cited text no. 13
Ippolito M, Vitale F, Accurso G, Iozzo P, Gregoretti C, Giarratano A, et al. Medical masks and respirators for the protection of healthcare Workers from SARS-CoV-2 and other viruses. Pulmonology 2020;26:204-12.  Back to cited text no. 14
Gómez-Ochoa SA, Muka T. Meta-analysis on facemask use in community settings to prevent respiratory infection transmission shows no effect. Int J Infect Dis 2021;103:257-9.  Back to cited text no. 15
Johansson MA, Quandelacy TM, Kada S, Prasad PV, Steele M, Brooks JT, et al. SARS-CoV-2 transmission from people without COVID-19 symptoms. JAMA Netw Open 2021;4:e2035057.  Back to cited text no. 16
Gómez-Ochoa SA, Franco OH, Rojas LZ, Raguindin PF, Roa-Díaz ZM, Wyssmann BM, et al. COVID-19 in health-care workers: A living systematic review and meta-analysis of prevalence, risk factors, clinical characteristics, and outcomes. Am J Epidemiol 2021;190:161-75.  Back to cited text no. 17
Li Y, Liang M, Gao L, Ayaz Ahmed M, Uy JP, Cheng C, et al. Face masks to prevent transmission of COVID-19: A systematic review and meta-analysis. Am J Infect Control 2021;49:900-6.  Back to cited text no. 18
Tian C, Lovrics O, Vaisman A, Chin KJ, Tomlinson G, Lee Y, et al. Risk factors and protective measures for healthcare worker infection during highly infectious viral respiratory epidemics: A systematic review and meta-analysis. Infect Control Hosp Epidemiol 2021 Jan 25: 1-12.  Back to cited text no. 19
Chu DK, Akl EA, Duda S, Solo K, Yaacoub S, Schünemann HJ, et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: A systematic review and meta-analysis. Lancet 2020;395:1973-87.  Back to cited text no. 20
Tabatabaeizadeh SA. Airborne transmission of COVID-19 and the role of face mask to prevent it: A systematic review and meta-analysis. Eur J Med Res 2021;26:1.  Back to cited text no. 21
Lewallen S, Courtright P. Epidemiology in practice: Case-control studies. Community Eye Health 1998;11:57-8.  Back to cited text no. 22
Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JP, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. J Clin Epidemiol 2009;62:e1-34.  Back to cited text no. 23
Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of observational studies in epidemiology: A proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 2000;283:2008-12.  Back to cited text no. 24
Garritty C, Gartlehner G, Nussbaumer-Streit B, King VJ, Hamel C, Kamel C, et al. Cochrane rapid reviews methods group offers evidence-informed guidance to conduct rapid reviews. J Clin Epidemiol 2021;130:13-22.  Back to cited text no. 25
Stang A. Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol 2010;25:603-5.  Back to cited text no. 26
Chatterjee P, Anand T, Singh KJ, Rasaily R, Singh R, Das S, et al. Healthcare workers & SARS-CoV-2 infection in India: A case-control investigation in the time of COVID-19. Indian J Med Res 2020;151:459-67.  Back to cited text no. 27
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Rodriguez-Lopez M, Parra B, Vergara E, Rey L, Salcedo M, Arturo G, et al. A case-control study of factors associated with SARS-CoV-2 infection among healthcare workers in Colombia. BMC Infect Dis 2021;21:878.  Back to cited text no. 28
Gonçalves MR, dos Reis RC, Tólio RP, Pellanda LC, Schmidt MI, Katz N, et al. Social distancing, mask use and the transmission of SARS-CoV-2: A population-based case-control study. Concalves 2020;27:2135-2143.  Back to cited text no. 29
Thomas DR, Fina L, Adamson J, Sawyer C, Jones A, Nnoaham K, et al. Social, demographic and behavioural determinants of SARS-CoV-2 infection: A case-control study carried out during mass community testing of asymptomatic individuals in South Wales, December 2020. medRxiv 2021.  Back to cited text no. 30
Dev N, Meena RC, Gupta DK, Gupta N, Sankar J. Risk factors and frequency of COVID-19 among healthcare workers at a tertiary care centre in India: A case-control study. Trans R Soc Trop Med Hyg 2021;115:551-6.  Back to cited text no. 31
Doung-Ngern P, Suphanchaimat R, Panjangampatthana A, Janekrongtham C, Ruampoom D, Daochaeng N, et al. Case-control study of use of personal protective measures and risk for SARS-CoV 2 infection, Thailand. Emerg Infect Dis 2020;26:2607-16.  Back to cited text no. 32
Çelebi G, Pişkin N, Çelik Bekleviç A, Altunay Y, Salcı Keleş A, Tüz MA, et al. Specific risk factors for SARS-CoV-2 transmission among health care workers in a university hospital. Am J Infect Control 2020;48:1225-30.  Back to cited text no. 33
Lio CF, Cheong HH, Lei CI, Lo IL, Yao L, Lam C, et al. Effectiveness of personal protective health behaviour against COVID-19. BMC Public Health 2021;21:827.  Back to cited text no. 34
Guo X, Wang J, Hu D, Wu L, Gu L, Wang Y, et al. Survey of COVID-19 disease among orthopaedic surgeons in Wuhan, People's Republic of China. J Bone Joint Surg Am 2020;102:847-54.  Back to cited text no. 35
Alsaïdi I, De Sousa Santos F, Plard B, Janvier E, Tinland A, Hafni A, et al. Factors associated with SARS-CoV2 infection and care pathways among the most vulnerable populations living in Marseille: A case control study. BMC Public Health 2021;21:1704.  Back to cited text no. 36
Abolnezhadian F, Jaafarzadeh N, Maraghi E, Abdullatif khafaie M, Montazeri A, Karimy M, et al. Non-Adherence to preventive behaviors and the risk of COVID-19: A comparative study. Med J Islam Repub Iran 2022;36:475-80.  Back to cited text no. 37
Prather KA, Marr LC, Schooley RT, McDiarmid MA, Wilson ME, Milton DK. Airborne transmission of SARS-CoV-2. Science 2020;370:303-4.  Back to cited text no. 38
Yu IT, Li Y, Wong TW, Tam W, Chan AT, Lee JH, et al. Evidence of airborne transmission of the severe acute respiratory syndrome virus. N Engl J Med 2004;350:1731-9.  Back to cited text no. 39
Adhikari U, Chabrelie A, Weir M, Boehnke K, McKenzie E, Ikner L, et al. A case study evaluating the risk of infection from middle eastern respiratory syndrome coronavirus (MERS-CoV) in a Hospital setting through bioaerosols. Risk Anal 2019;39:2608-24.  Back to cited text no. 40
Chia PY, Coleman KK, Tan YK, Ong SW, Gum M, Lau SK, Lim XF, Lim AS, Sutjipto S, Lee PH, Son TT. Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients. Nature Communications 2020;11:1-7.  Back to cited text no. 41
Santarpia JL, Rivera DN, Herrera V, Morwitzer MJ, Creager H, Santarpia GW, et al. Aerosol and surface transmission potential of SARS-CoV-2. medRxiv 2020:10-24.  Back to cited text no. 42
Liu Y, Ning Z, Chen Y, Guo M, Liu Y, Gali NK, et al. Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. Nature 2020;582:557-60.  Back to cited text no. 43
Guo ZD, Wang ZY, Zhang SF, Li X, Li L, Li C, et al. Aerosol and surface distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards, Wuhan, China, 2020. Emerg Infect Dis 2020;26:1583-91.  Back to cited text no. 44
Davies A, Thompson KA, Giri K, Kafatos G, Walker J, Bennett A. Testing the efficacy of homemade masks: Would they protect in an influenza pandemic? Disaster Med Public Health Prep 2013;7:413-8.  Back to cited text no. 45
MacIntyre C, Dung C, Seale H. COVID-19: Should cloth masks be used by healthcare workers as a last resort? BMJ 2020;20:43.  Back to cited text no. 46
Feng S, Shen C, Xia N, Song W, Fan M, Cowling BJ. Rational use of face masks in the COVID-19 pandemic. Lancet Respir Med 2020;8:434-6.  Back to cited text no. 47
Ellingson K, Haas JP, Aiello AE, Kusek L, Maragakis LL, Olmsted RN, et al. Strategies to prevent healthcare-associated infections through hand hygiene. Infect Control Hosp Epidemiol 2014;35:937-60.  Back to cited text no. 48
Tini G, Duso BA, Bellerba F, Corso F, Gandini S, Minucci S, et al. Semantic and Geographical analysis of COVID-19 trials reveals a fragmented clinical research landscape likely to impair informativeness. Front Med (Lausanne) 2020;7:367.  Back to cited text no. 49