Does a respirator/KN95/N95 mask reduce the chance of the wearer contracting COVID-19?

Last updated: February 20, 2022
Yes. All the studies in this list that examine the question agreed on this conclusion. We identified all of these studies as literature reviews, which are studies that review and often evaluate the findings of many studies on a question. This gives us more confidence that the answer is correct.
This short answer was generated by aggregating the answers that each of the studies below gave to the question (as indicated by State of K members) and adjusting for source quality and other factors. If key studies are missing or the answers attributed to individual studies are incorrect, the above answer could be wrong. For medical questions, don't rely on the information here. Consult a medical professional.
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YES ANSWERS
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NO ANSWERS
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NO DATA ON ANSWER


Chart summary of 6 studies examining this question

All answers are assigned by State of K users. The label Couldn't Identify means that State of K was not able to determine whether a study answers the question "yes" or "no". This could be due to several factors. One possibility is that a study found some evidence to indicate that the answer to the question is "yes" and some evidence to indicate that the answer is "no". This often happens when a study uses two or more proxies to study the same phenomenon (i.e. firearm sales figures and self-reported firearm ownership rates as proxies for the prevalence of firearms) and the proxies yield different results when looking for correlations with another phenomenon (i.e. firearm-related deaths). Alternatively, the label may be applied if the phenomenon under study (i.e. whether breast milk improves cognitive function) is true for one group, but not another (i.e. true for girls, but not for boys). Yet another possibility is that a study found there was insufficient evidence to reach a conclusion regarding the question. Finally, the full text or abstract of a study may not have been written clearly or was inaccessible. This would make it difficult to determine how a study answered a question.

All labels of Literature Reviews and source quality are assigned by State of K. All labels of High Quality Source are assigned based on whether the publication in which the article appeared was ranked as Q1 by Scimago Institutions Rankings. Certain well-regarded think tanks are also given this label.

Literature Reviews
Although we recommend you consider all of the studies below, we believe the following studies are literature reviews, which survey and evaluate many studies on this question:

SUMMARIES OF STUDIES
Total studies in list: 6
Sorted by publication year
1
N95 respirator and surgical mask effectiveness against respiratory viral illnesses in the healthcare setting: A systematic review and meta-analysis
"Objective: To examine the results, level of evidence, and methodologic quality of original studies regarding surgical mask effectiveness in minimizing viral respiratory illness transmission, and, in particular, the performance of the N95 respirator versus surgical mask.Methods: Meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with use of PubMed, MEDLINE, and the Cochrane Library databases.Results: Eight studies (9164 participants) were included after screening 153 articles. Analyses showed statistically significant differences between N95 respirator versus surgical mask use to prevent influenza-like-illness (risk ratio [RR] = 0.81, 95% confidence interval [CI] = 0.68-0.94, P < 0.05), non-influenza respiratory viral infection (RR = 0.62, 95% CI = 0.52-0.74, P < 0.05), respiratory viral infection (RR = 0.73, 95% CI = 0.65-0.82, P < 0.05), severe acute respiratory syndrome coronavirus (SARS-CoV) 1 and 2 virus infection (RR = 0.17, 95% CI = 0.06-0.49, P < 0.05), and laboratory-confirmed respiratory viral infection (RR = 0.75, 95% CI = 0.66-0.84, P < 0.05). Analyses did not indicate statistically significant results against laboratory-confirmed influenza (RR = 0.87, CI = 0.74-1.03, P > 0.05).Conclusions: N95 respirator use was associated with fewer viral infectious episodes for healthcare workers compared with surgical masks. The N95 respirator was most effective in reducing the risk of a viral infection in the hospital setting from the SARS-CoV 1 and 2 viruses compared to the other viruses included in this investigation. Methodologic quality, risk of biases, and small number of original studies indicate the necessity for further research to be performed, especially in front-line healthcare delivery settings."
AUTHORS
Daryl C Osbahr
Ibrahim Mamdouh Zeini
Naser Mubarak
Sunny Gupta
Benjamin C Service
Andrew P Collins et al
PUBLISHED
2021 Journal of the American College of Emergency Physicians Open
Literature Review
Yes
Yes
2
Facemask and Respirator in Reducing the Spread of Respiratory Viruses; a Systematic Review
"Introduction: Respiratory viruses spread fast, and some manners have been recommended for reducing the spread of these viruses, including the use of a facemask or respirator, maintaining hand hygiene, and perfoming social distancing. This systematic review aimed to assess the impact of facemasks and respirators on reducing the spread of respiratory viruses.Methods: We conducted a systematic review using MeSH terms, and reported findings according to PRISMA. PubMed, Embase, Cochrane Library, Scopus, ProQuest, Web of Science(WoS), and Google Scholar were searched for articles published between 2009 and 2020. Two independent reviewers determined whether the studies met inclusion criteria. The risk of bias of studies was assessed using Newcastle-Ottawa (NOS) and Consolidated Standards of Reporting Trials (CONSORT).Results: A total of 1505 articles were initially retrieved and 10 were finally included in our analysis (sample size: 3065). 96.8% of non-infected participants used facemask or respirator in contact with people infected with a respiratory virus, facemask and respirator have a significant effect on reducing the spread of respiratory viruses.Conclusion: Evidence support that using a facemask or respirator can reduce the spread of all types of respiratory viruses; therefore, this result can be generalized to the present pandemic of a respiratory virus (SARS-COV-2) and it is recommended to use a facemask or respirator for reducing the spread of this respiratory virus."
AUTHORS
Mohammad Darvishmotevalli
Negar Shaterian
Zahra Atarodi Kashani
Fatemeh Abdi
Negin Shaterian
PUBLISHED
2021 Archives of Academic Emergency Medicine
Literature Review
Yes
Yes
3
Protection From COVID-19: The Efficacy of Face Masks
"Background: Since the beginning of 2020 the SARS-CoV-2 virus has spread to nearly every country in the world. The mainly airborne pathogen has led to large numbers of deaths, principally in elderly and vulnerable segments of the population. Protective vaccines have recently become available, but it is not yet clear whether and when population-wide immunity will be achieved. The existence of evidence for the protective effect of masks covering the mouth and nose is a topic of public debate.Methods: A selective literature search was carried out in PubMed. Data from the German Robert Koch Institute and the Centers for Disease Control and Prevention were also taken into account.Results: When talking, as many as 20 000 droplets ranging in size from 20 to 500 µM are released every second. According to PCR tests, the amount of virus exhaled is highest immediately before the onset of symptoms. No randomized trials have been conducted on the effect of masks covering the mouth and nose. A meta-analysis of 29 studies on infection with SARS-CoV-2, SARS, or MERS revealed that type N-95 masks (corresponding approximately to FFP-2), surgical masks, or similar multilayer cotton masks can greatly reduce the infection risk for the wearers (RR 0.34 [0.26; 0.45], with moderate heterogeneity [I2 = 48%]). Model experiments and case reports suggest that masks covering the mouth and nose afford considerable protection against transmission of SARS-CoV-2 and other airborne diseases by reducing release of and exposure to potentially infectious droplets; in addition, infections that do occur take a milder course. A limitation of the studies analyzed is that in most cases, this effect cannot be viewed in isolation from the protective impact of other measures (distancing, hygiene precautions).Conclusion: It can plausibly be assumed that consistent use of masks covering the mouth and nose can play an important role in containing the spread of SARS-CoV-2."
AUTHOR
Hemmer, C J
PUBLISHED
2021 Dtsch Arztebl Int
Literature Review
Yes
Yes
4
The Need of Health Policy Perspective to Protect Healthcare Workers During COVID-19 Pandemic. A GRADE Rapid Review on the N95 Respirators Effectiveness
"Protecting Health Care Workers (HCWs) during routine care of suspected or confirmed COVID-19 patients is of paramount importance to halt the SARS-CoV-2 (Severe Acute Respiratory Syndrome-Coronavirus-2) pandemic. The WHO, ECDC and CDC have issued conflicting guidelines on the use of respiratory filters (N95) by HCWs. We searched PubMed, Embase and The Cochrane Library from the inception to March 21, 2020 to identify randomized controlled trials (RCTs) comparing N95 respirators versus surgical masks for prevention of COVID-19 or any other respiratory infection among HCWs. The grading of recommendations, assessment, development, and evaluation (GRADE) was used to evaluate the quality of evidence. Four RCTs involving 8736 HCWs were included. We did not find any trial specifically on prevention of COVID-19. However, wearing N95 respirators can prevent 73 more (95% CI 46-91) clinical respiratory infections per 1000 HCWs compared to surgical masks (2 RCTs; 2594 patients; low quality of evidence). A protective effect of N95 respirators in laboratory-confirmed bacterial colonization (RR = 0.41; 95%CI 0.28-0.61) was also found. A trend in favour of N95 respirators was observed in preventing laboratoryconfirmed respiratory viral infections, laboratory-confirmed respiratory infection, and influenza like illness. We found no direct high quality evidence on whether N95 respirators are better than surgical masks for HCWs protection from SARS-CoV-2. However, low quality evidence suggests that N95 respirators protect HCWs from clinical respiratory infections. This finding should be contemplated to decide the best strategy to support the resilience of healthcare systems facing the potentially catastrophic SARS-CoV-2 pandemic."
AUTHOR
Primiano Iannone
PUBLISHED
2020 PLoS One
Literature Review
High Quality Source
Yes
Yes
5
Masks or N95 Respirators During COVID-19 Pandemic–Which One Should I Wear?
"PurposeCoronavirus Disease 2019 (COVID-19) has caused suffering and death around the world. Careful selection of facial protection is paramount for preventing virus spread among healthcare workers and preserving mask and N95 respirator supplies.MethodsThis paper is a comprehensive review of literature written in English and available on Pubmed comparing the risk of viral respiratory infections when wearing masks and N95 respirators. Current international oral and maxillofacial surgery guidelines for mask and N95 respirator use, patient COVID-19 disease status, aerosol producing procedures were also collected and incorporated into a workflow for selecting appropriate facial protection for oral and maxillofacial surgery procedures during the current pandemic.ResultsMost studies suggest N95 respirators and masks are equally protective against respiratory viruses. Some evidence favors N95 respirators, which are preferred for high-risk procedures when aerosol production is likely or when the COVID-19 status of a patient is positive or unknown. N95 respirators may also be used for multiple patients or reused depending on the type of procedure and condition of the respirator after each patient encounter.ConclusionN95 respirators are preferred over masks against viral respiratory pathogens, especially during aerosol-generating procedures or when a patient’s COVID-19 status is positive or unknown."
AUTHOR
Mingzhu Zhang
PUBLISHED
2020 Journal of Oral and Maxillofacial Surgery
Literature Review
Yes
Yes
6
Effectiveness of Masks and Respirators Against Respiratory Infections in Healthcare Workers: A Systematic Review and Meta-Analysis
"This systematic review and meta-analysis quantified the protective effect of facemasks and respirators against respiratory infections among healthcare workers. Relevant articles were retrieved from Pubmed, EMBASE, and Web of Science. Meta-analyses were conducted to calculate pooled estimates. Meta-analysis of randomized controlled trials (RCTs) indicated a protective effect of masks and respirators against clinical respiratory illness (CRI) (risk ratio [RR] = 0.59; 95% confidence interval [CI]:0.46-0.77) and influenza-like illness (ILI) (RR = 0.34; 95% CI:0.14-0.82). Compared to masks, N95 respirators conferred superior protection against CRI (RR = 0.47; 95% CI: 0.36-0.62) and laboratory-confirmed bacterial (RR = 0.46; 95% CI: 0.34-0.62), but not viral infections or ILI. Meta-analysis of observational studies provided evidence of a protective effect of masks (OR = 0.13; 95% CI: 0.03-0.62) and respirators (OR = 0.12; 95% CI: 0.06-0.26) against severe acute respiratory syndrome (SARS). This systematic review and meta-analysis supports the use of respiratory protection. However, the existing evidence is sparse and findings are inconsistent within and across studies. Multicentre RCTs with standardized protocols conducted outside epidemic periods would help to clarify the circumstances under which the use of masks or respirators is most warranted."
AUTHORS
Clarence C Tam
Mabel Sheau Fong Low
Chee Fu Yung
Vittoria Offeddu
PUBLISHED
2017 Clinical Infectious Diseases
Literature Review
High Quality Source
Yes
Yes