| MacIntyre CR et al. 2016 |
Randomized cluster-type clinical trial |
Patients from 18 year of age on with ILI (body temperature ≥38º C plus one respiratory symptom, including cough, nasal congestion, coryza, sore throat or sneezes) who attended an outpatient clinic during the study period, without history of ILI among family members in the previous 14 days and who lived with at least two other people at home |
3M 1817 Surgical Mask |
Hand washing when wearing or removing the mask |
Non-mask use |
Clinical symptoms of respiratory disease, ILI andlaboratory-confirmed viral respiratory infection |
In intention-to-treat analysis, clinical respiratory disease rates of[relative risk (RR) 0.61, 95% CI 0.18 to 2.13], ILI [RR 0.32, 95% CI 0.03 to 3.13] and laboratory-confirmed viral infections [RR 0.97, 95% CI 0.06 to 15.54] were consistently lower in the mask group compared to the control group, although not statistically significant. Viruses were isolated from 60% (146/245) of the index cases. Influenza was the most common virus isolated from 115 (47%) cases - influenza A - 100, influenza B -11 and influenza A and B - 4. Other viruses isolated from index cases were rhinovirus, NL63 and C229E. More than one virus was isolated in 48 (20%) index cases, including 17 influenza co-infections. |
Unclear risk of bias. Although they are an apparent methodological rigorous investigations, information about the randomization method of the research subjects is not provided. In addition, the intervention group, associated with the use of masks, also received information on frequent hand washing. This may have contributed to the noted difference, even if not a statistically significant one. The t 3M contributed with masks and respirators supplies and the study received research grants and laboratory tests from Pfizer, GSK and Bio-CSL. One of the authors also received funding for the GSK vaccine, bio-CSL and Saniofi Pasteur to conduct the research / ROB 2.0 |
Benkouiten S et al.
2014 |
Systematic review |
Pilgrims (regardless of age and sex) from the Hajj Muslim festival |
Surgical mask (no description) |
Hand hygiene, cough etiquette and disposable tissue, social distancing and contact prevention, Hajj postponementment for populations at risk |
Lack of nonpharmaceutical interventions |
Preventive effect on respiratory infectious diseases |
The effectiveness of face mask use in preventing respiratory disease during Hajj was assessed in several studies. However, the results were conflicting. A study among Indonesian pilgrims reported that those who did not use a face mask during Hajj had three times more risk of getting an acute upper respiratory tract infection compared to those with face masks. A significant reduction in respiratory symptoms was also observed in a Saudi study, while several other studies reported no significant effect. A second Saudi study showed a significant reduction in respiratory symptoms with face mask use, but only in the male or total sample, not in the female group. Two other studies addressed the impact of face mask use during Hajj on the prevalence of respiratory symptoms and viral pathogens using PCR assays of pilgrims' nasal samples, and no significant effects were observed. |
Study of low quality. The review does not present methodological and systematic rigor /AMSTAR |
| Liang M, et al. 2020 |
Systematic review and meta-analysis |
Healthcare workers and non-healthcare workers in Asia and Western countries |
Face mask (no specification) |
Influenza vaccination, hand hygiene |
Not using masks |
Viral respiratory infection (influenza, SARS, SARS-CoV-2 e H1N1) diagnosed in laboratory |
After wearing a mask, the risk of getting viral respiratory infection was significantly reduced:OR was 0.35 and 95% CI = 0.24-0.51 [I2 = 60%, random effect MH model].Only in the subgroup of healthcare workers, the protective effect was more obvious, with an OR of 0.20 [95% CI = 0.11-0.37, I2 = 59%]. In a study about COVID-19, the OR was 0.04 (95% CI = 0.00-0.60). In the subgroup of non-healthcare workers, a protective effect was found with the cluster OR of 0.53 [95% CI = 0.36 - 0.79, I2 = 45%].A more detailed description found significant effects in the household subgroup [OR = 0.60, 95% CI = 0.37-0.97，I2 = 31%] and the non-household subgroup [OR = 0.44, 95% CI = 0 , 33-0.59 I2 = 54%]. One study included healthcare workers and family members of patients, with an OR of 0.74 [95% CI: 0.29-1.90].By geographic locations, positive effects of masks protection were found in Asia [OR = 0.31, 95% CI = 0.19-0.50, I2 = 65%] and in Western countries [OR = 0.45 , 95% CI = 0.24-0.83, I2 = 51%]. Healthcare professionals in Asia [OR = 0.21, 95% CI = 0.11-0.41, I2 = 64%] and in Western countries [OR = 0.11, 95% CI = 0.02-0, 51, I2 = 0%] can significantly reduce the risk by using masks.In the non-healthcare workers subgroup, protection was found in Western countries [OR = 0.46, 95% CI = 0.34-0.63, I2 = 57%] and Asia [OR = 0.51, 95% CI = 0.34-0.78, I2 = 45%]. The masks presented a protective effect against influenza viruses [OR = 0.55, 95% CI = 0.39-0.76, I2 = 27%], SARS [OR = 0.26, 95% CI = 0.18 -0.37, I2 = 47%] and SARS-CoV-2 [OR = 0.04, 95% CI = 0.00-0.60, I2 = 0%]. However, there was no significant protective effect against H1N1[OR = 0.30, 95% CI = 0.08-1.16, I2 = 51%]. |
Low risk of bias. The study presents high methodological rigor in the systematic review and meta-analysis, with a clear and adequate description of the methodology / AMSTAR |
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