Meta-analysis on facemask use in community settings to prevent respiratory infection transmission shows no effect

We read with interest the systematic review and meta-analysis by Chaabna et al. aiming at synthesizing available evidence on effectiveness of facemasks to prevent transmission respiratory infections in community setting (Chaabna al., 2020Chaabna K. Doraiswamy S. Mamtani R. Cheema Facemask use settings infection transmission: a rapid meta-analysis.Int J Infect Dis. 2020; (S1201-9712(20)32150-0)https://doi.org/10.1016/j.ijid.2020.09.1434Abstract Full Text PDF Scopus (29) Google Scholar). The authors reported an apparent benefit use, which showed significant reduction risk influenza, influenza-like illness, severe acute syndrome coronavirus (SARS-CoV), SARS-CoV-2 (pooled OR = 0.66, 95% confidence interval: 0.54–0.81). However, there are several methodological flaws study that might have led misleading conclusions. In meta-analyses influenza outcomes, first meta-analyzed both clinical trials case-control/retrospective observational studies, last studies overestimating effect. Second, included five did not only face mask as intervention but were additionally introducing other interventions such hand hygiene same group (Aiello 2012Aiello A.E. Perez V. Coulborn R.M. Davis B.M. Uddin M. Monto A.S. Facemasks, hygiene, among young adults: randomized trial.PloS One. 2012; 7e29744Crossref PubMed (129) Scholar, Aiello 2010Aiello Murray G.F. al.Mask seasonal illness trial.J 2010; 201: 491-498Crossref (238) Cowling 2009Cowling B.J. Chan K.-H. Fang V.J. Cheng C.K.Y. Fung R.O.P. Wai W. al.Facemasks households: cluster trial.Ann Intern Med. 2009; 151: 437-446Crossref (411) Simmerman 2011Simmerman J.M. Suntarattiwong P. Levy J. Jarman R.G. Kaewchana Gibbons R.V. al.Findings from household controlled trial washing masks reduce Bangkok, Thailand.Influenza Other Respir Viruses. 2011; 5: 256-267Crossref (120) Suess 2012Suess T. Remschmidt C. Schink S.B. Schweiger B. Nitsche A. Schroeder al.The role prevention results randomised trial; Berlin, Germany, 2009–2011.BMC 12: 26Crossref Scholar), condition limits attribution any observed effect facemask only. Therefore, their conclusion, "there is enough medical effective viral infections," supported analyses Based ten meta-analysis, we reviewed reanalyzed data compare whether sole was associated setting. From RCTs al.'s study, compared alone versus control group, while three combined handwashing As Figure 1, no differences between controls odds developing laboratory-confirmed illness. Similarly, when comparing solely handwashing, indicating reducing infection. Given used masks, cloth masks' efficacy expected be even lower; higher health care personnel using than (MacIntyre 2015MacIntyre C.R. Seale H. Dung T.C. Hien N.T. Nga P.T. Chughtai A.A. al.A healthcare workers.BMJ Open. 2015; 5e006577Crossref (260) Several reviews suggest potential infections; however, most them include mostly non-randomized serious issues, mainly derived (Chu 2020Chu D.K. Akl E.A. Duda Solo Yaacoub Schünemann H.J. al.Physical distancing, eye protection person-to-person COVID-19: meta-analysis.Lancet Lond Engl. 395: 1973-1987Abstract (2185) Liang 2020Liang Gao L. Zhou Q. Uy J.P. Heiner al.efficacy preventing virus meta-analysis.Travel Med (101751–101751)Crossref (231) On hand, Saunders-Hastings protective regular regarding 2009 pandemic (OR 0.62; CI 0.52–0.73; I2 0%), finding 0.53; 0.16–1.71; 48%) (Saunders-Hastings 2017Saunders-Hastings Crispo J.A.G. Sikora Krewski D. Effectiveness personal measures meta-analysis.Epidemics. 2017; 20: 1-20Crossref (95) Because these divergent lack high-quality research this area, strong recommendations for context should issued caution until new show effectiveness. This more important, considering headache incidence worsening preexisting (Lim 2006Lim E.C.H. Seet R.C.S. Lee Wilder-Smith E.P.V. Chuah B.Y.S. Ong B.K.C. Headaches N95 amongst providers.Acta Neurol Scand. 2006; 113: 199-202Crossref (159) Rebmann 2013Rebmann Carrico Wang Physiologic effects compliance long-term respirator intensive unit nurses.Am Control. 2013; 41: 1218-1223Abstract (141) Szeinuk 2000Szeinuk Beckett W.S. Clark N. Hailoo W.L. Medical evaluation use.Am Ind 2000; 37: 142-157Crossref (44) Radonovich, 2009Radonovich L.J. Respirator tolerance workers.JAMA. 301: 36Crossref (148) Shenal 2011Shenal B.V. Radonovich Hodgson Bender B.S. Discomfort exertion prolonged wear setting.J Occup Environ Hyg. 9: 59-64Crossref (86) No conflict declare.