New evidence suggests masks may be linked to reduced risk of SARS-CoV-2 infection

In a recently published rapid review, Annals of Internal Medicine Researchers presented the latest live evidence of the efficacy of masks in preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in communities and healthcare settings.

They independently synthesized evidence from both settings and from randomized controlled trials (RCTs) and observational studies.

study: Major update: Masks for the prevention of SARS-CoV-2 in healthcare and the community — final update of live rapid review. Image credit: Perfect Wave/Shutterstock.com

Background

Masks transmit coronavirus disease 2019 (COVID-19, a deadly infectious disease caused by SARS-CoV-2) in various environments such as homes, outdoors, community places, and workplaces such as offices Respiratory protection that reduces risk. Hospitals with widely varying levels of viral exposure.

Other factors that influence the effectiveness of masking include circulating virus variants and their level of transmission, individual immunity levels, and behaviors (such as adherence to infection prevention measures).

However, it remains unclear to what extent mask use can protect against COVID-19 in different settings.

In June 2020, the authors published the first rapid review of associations between mask use and risk of other respiratory infections such as SARS-CoV-2 and influenza.

Subsequently, on the basis of moderate-strength evidence collected from two RCTs and 10 observational studies, a further 8 demonstrate an association between mask use and reduced risk of SARS-CoV-2 infection in the community. announced the latest information.

About research

In this study, researchers focused on obtaining up-to-date evidence (data) on the usefulness of three types of masks that differ in fit and filtration: N95 masks, surgical masks, and cloth masks. . efficacyand fluid resistance in preventing SARS-CoV-2 infection in different settings, based on 3 RCTs and 21 observational studies.

The research team obtained these RCTs and studies from PubMed, MEDLINE, Elsevier EMBASE and medRxiv through an extensive search conducted from June 3, 2022 to January 2, 2023.

Additionally, the researchers used a modern protocol for this study. As such, they relied on studies that focused solely on self-reports and non-peer-reviewed studies on diagnosing SARS-CoV-2 infection.

In addition, we removed questions about influenza or influenza-like illness, SARS-CoV-1, Middle East Respiratory Syndrome (MERS) coronavirus infection.

We also used standard systematic review techniques such as double abstract review. Overall, in this study, the researcher focused on his two key questions:

i) What is the efficacy and comparative effectiveness of respirators (N95 or similar masks), cloth masks, and face masks (surgical) in preventing SARS-CoV-2 infection in high-risk and non-high-risk settings? ?

ii) Does extending or reusing N95 masks prevent SARS-CoV-2 transmission?

Findings included clinically assessed risks associated with SARS-CoV-2 infection. Finally, the team updated the evidence map showing the strength of the evidence (high, medium, low, or inconclusive due to insufficient evidence) and the direction of impact for each mask comparison across both settings.

result

As with the previous update, the authors found low-to-moderate strength evidence for the community environment through RCTs, suggesting that mask use reduced the risk of SARS-CoV-2 infection by 10% compared with no mask. suggested an 18% reduction from

Given the cumulative effects of masking over time, this could have significant implications at the population level.

Only one RCT did not consider masks as a source of infection control and documented inaccurate estimates. Two other RCTs with different interventions and settings found that interventions aimed at increasing mask use reduced the risk of SARS-CoV-2 infection.

Observational studies have consistently found that wearing a mask reduces the risk of SARS-CoV-2 infection compared to not wearing a mask in the community.

The strength of the evidence for surgical masks versus cloth masks, more versus fewer, and consistent masks remained insufficient.

In medical settings, a recent RCT found that surgical masks were no less effective than N95 masks in routine patient care, but the strength of the evidence was low. Also, this analysis after the fact Based on self-reported viral exposure.

The results did not change after stratifying patients based on non-occupational exposure. Furthermore, although this RCT was conducted in four countries, Egypt, Pakistan, Canada and Israel, the countries differed in terms of vaccination coverage and Covid-19 seroprevalence, to name a few.

Due to methodological limitations and inconsistencies, all included observational studies provided inadequate evidence of the utility and risk of COVID-19 of N95 versus surgical masks in healthcare settings.

Of note, observational studies primarily assessed outcomes related to actual mask use, whereas RCTs assessed all interventions promoting increased mask use.

Therefore, a new RCT that compared different types of masks in healthcare settings prompted researchers to share this update.

Finally, researchers found limited evidence of the harm of masking. Only one new RCT demonstrated that N95 use increased the risk of mask-related harm compared to surgical masks. However, no serious events were observed with N95 use.

Conclusion

This final update differed from previous systematic reviews of masks as it focused exclusively on SARS-CoV-2 infections and included new RCTs. Additionally, they prospectively modified the study protocol to focus on higher quality studies and more relevant evidence.

Despite the limitations of the evidence base and review process, the exclusion of some previously included studies did not affect our current findings.

Future studies with sufficient statistical power for primary and stratified analyses, may clarify the comparative effectiveness of masks in preventing SARS-CoV-2 infection.

Additionally, a suitable method should be used to describe the main characteristics, harms, benefits and compliance requirements of the mask.

In conclusion, this update demonstrates that both surgical masks and N95 masks similarly reduce the risk of SARS-CoV-2 infection in healthcare settings, and the usefulness of N95 masks should not be overlooked.