A recent article published in the Annals of Internal Medicine illustrated the eight update alert of the review on masks for preventing respiratory virus infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in healthcare and community settings.
Until recently, there have been eight updates to the living rapid review titled "masks for prevention of respiratory virus infections, including SARS-CoV-2, in healthcare and community settings". The update interval was changed to bimonthly following the initial three monthly updates. Further, the gap was extended twice a year, starting in June 2021.
About the study
The authors present the eighth update alert for the living rapid review on the use of masks for the prevention of respiratory virus infections, including SARS-CoV-2, in health care and community settings in the present letter.
Adopting the same search techniques as the original review, searches for this update were conducted from December 3, 2021, to June 2, 2022. Inclusion was limited to observational investigations and randomized studies that accounted for confounders. Studies that were not peer-reviewed were disregarded unless they used information gathered after February 2021 to document mask use during the periods when the SARS-CoV-2 Delta (B.1.617.2) and Omicron (B.1.1.529) variants predominated.
The researchers noted that three recent observational studies, all conducted in the United States, assessed the relationship between mask usage in community settings and the probability of contracting SARS-CoV-2.
In the current update, two new observational examinations found that mask use was linked to a lower risk of coronavirus disease 2019 (COVID-19), in line with earlier studies. In one recent study, the adjusted odds ratio (OR) for mask wearing in public indoor settings compared to no use was 0.51. Compared to not wearing a mask, the second non-peer-reviewed assessment indicated that mask usage was associated with a lower risk of SARS-CoV-2 infection for any interaction taking place <6 feet of distance.
The COVID-19 risk decrease associated with wearing a mask was comparable in the pre-Delta and Delta-predominant periods. However, it was dropped in the Omicron-predominant era. The evidence supporting the advantages of mask usage as opposed to not using one for preventing SARS-CoV-2 infection in the community continues to be low to moderate because the new evaluations were observational and bore methodological constraints.
According to one of the novel fair-quality studies, the use of surgical masks, KN95 respirators, or N95 respirators was each linked to a lower risk of SARS-CoV-2 infection than not wearing a mask. Using a cloth mask lowered the chance of infection compared to not using one, but the estimate remained uncertain. The research did not include risk comparisons between different mask types.
Based on the adjusted estimations for masks against no masks supplied in the analysis, the scientists estimated adjusted ORs for KN95 and N95 respirators against surgical masks and cloth masks relative to surgical masks. Nevertheless, these adjusted ORs were not accurate.
The novel fair-quality research offered insufficient proof for N95 against surgical masks. It did not alter earlier conclusions of inadequate evidence for cloth masks and N95 respirators against no masks and no variation between cloth and surgical masks.
Another recent study assessed the relationship between health care professionals' compliance with mask usage when not at work and their chance of contracting SARS-CoV-2 infection. However, the estimate was unreliable. The strength of data supporting always wearing a mask against inconsistent mask usage in the community was minimal.
Health care settings
The team stated that two novel cohort analyses assessed mask use and SARS-CoV-2 infection risk in healthcare facilities. One research was a follow-up article for a priorly included study. N95 respirator usage was linked to an enhanced chance of COVID-19 relative to no use in univariate assessment. On the other hand, the correlation was statically insufficient in the multivariate evaluation to be incorporated into the multivariate model. As a result, the detected univariate correlation in healthcare professionals wearing N95 masks was probably caused by confounding brought on by elevated exposures or other variables. Moreover, the new study did not alter the earlier conclusion of insufficient evidence between N95 and no masks.
Another new research assessed the relationship between regular mask wearing and the probability of SARS-CoV-2 infection, though the estimate was very uncertain. As a result, there is still little evidence about the consistency of mask usage.
Overall, the scientists mentioned that 1592 citations were found during the eighth update searches for the review on the use of masks for prevention of respiratory virus infections, including SARS-CoV-2, in healthcare and community settings. Five new observational investigations and no new randomized controlled trials (RCTs) did not meet the inclusion criteria on the correlation between mask wear and SARS-CoV-2 infection. Two studies were carried out in healthcare settings, while three were in community settings.
Although one preprint research on mask usage in community settings compiled information during Omicron and Delta prevalent periods, the other experiments were conducted anterior to the appearance of these variants. Methodological flaws in every study included a low or unclear participation rate, inability to record attrition or missing data, and potential recall bias.
The eighth update was intended to be the last for the current review. Nonetheless, the researchers noted that a sizable randomized experiment comparing N95 to surgical masks had already been executed. Yet, the results have not been made public. One more update will be accomplished following its release because this experiment may impact the results of the current comparison.