Impact of respirator versus surgical masks on SARS-CoV-2 acquisition in healthcare workers: a prospective multicentre cohort

Predicting consequences of COVID-19 control measure de-escalation on nosocomial transmission and mortality: a modelling study in a French rehabilitation hospital

INTRODUCTION

Infection control measures are effective for nosocomial COVID-19 prevention but bear substantial health-economic costs, motivating their "de-escalation" in settings at low risk of SARS-CoV-2 transmission. Yet consequences of de-escalation are difficult to predict, particularly in light of novel variants and heterogeneous population immunity.

AIM

To estimate how infection control measure de-escalation influences nosocomial COVID-19 risk.

METHODS

An individual-based transmission model was used to simulate SARS-CoV-2 outbreaks and control measure de-escalation in a French long-term care hospital with multi-modal control measures in place (testing and isolation, universal masking, single-occupant rooms). Estimates of COVID-19 case fatality rates (CFRs) from reported outbreaks were used to quantify excess COVID-19 mortality due to de-escalation.

RESULTS

In a population fully susceptible to infection, de-escalating both universal masking and single rooms resulted in hospital-wide outbreaks of 114 (95% CI: 103-125) excess infections, compared with five (three to seven) excess infections when de-escalating only universal masking or 15 (11-18) when de-escalating only single rooms. When de-escalating both measures and applying CFRs from the first wave of COVID-19, excess patient mortality ranged from 1.57 (1.41-1.71) to 9.66 (8.73-10.57) excess deaths/1000 patient-days. By contrast, when applying CFRs from subsequent pandemic waves and assuming susceptibility to infection among 40-60% of individuals, excess mortality ranged from 0 (0-0) to 0.92 (0.77-1.07) excess deaths/1000 patient-days.

CONCLUSIONS

The de-escalation of bundled COVID-19 control measures may facilitate widespread nosocomial SARS-CoV-2 transmission. However, excess mortality is probably limited in populations at least moderately immune to infection and given CFRs resembling those estimated during the 'post-vaccine' era.

Association of protective behaviors with SARS-CoV-2 infection: results from a longitudinal cohort study of adults in the San Francisco Bay Area

PURPOSE

In an effort to decrease transmission during the first years of the COVID-19 pandemic, public health officials encouraged masking, social distancing, and working from home, and restricted travel. However, many studies of the effectiveness of these measures had significant methodologic limitations. In this analysis, we used data from the TrackCOVID study, a longitudinal cohort study of a population-based sample of 3846 adults in the San Francisco Bay Area, to evaluate the association between self-reported protective behaviors and incidence of SARS-CoV-2 infection.

METHODS

Participants without SARS-CoV2 infection were enrolled from August to December 2020 and followed monthly with testing and surveys (median of four visits).

RESULTS

A total of 118 incident infections occurred (3.0% of participants). At baseline, 80.0% reported always wearing a mask; 56.0% avoided contact with nonhousehold members some/most of the time; 9.6% traveled outside the state; and 16.0% worked 20 or more hours per week outside the home. Factors associated with incident infection included being Black or Latinx, having less than a college education, and having more household residents. The only behavioral factor associated with incident infection was working outside the home (adjusted hazard ratio 1.62, 95% confidence interval 1.02-2.59).

CONCLUSIONS

Focusing on protecting people who cannot work from home could help prevent infections during future waves of COVID-19, or future pandemics from respiratory viruses. This focus must be balanced with the known importance of directing resources toward those at risk of severe infections.

Masking strategy to protect healthcare workers from COVID-19: An umbrella meta-analysis

BACKGROUND

The burden of severe disease and death due to SARS-CoV-2 (COVID-19) pandemic among healthcare workers (HCWs) worldwide has been substantial. Masking is a critical control measure to effectively protect HCWs from respiratory infectious diseases, yet for COVID-19, masking policies have varied considerably across jurisdictions. As Omicron variants began to be predominant, the value of switching from a permissive approach based on a point of care risk assessment (PCRA) to a rigid masking policy needed to be assessed.

METHODS

A literature search was conducted in MEDLINE (Ovid platform), Cochrane Library, Web of Science (Ovid platform), and PubMed to June 2022. An umbrella review of meta-analyses investigating protective effects of N95 or equivalent respirators and medical masks was then conducted. Data extraction, evidence synthesis and appraisal were duplicated.

RESULTS

While the results of Forest plots slightly favoured N95 or equivalent respirators over medical masks, eight of the ten meta-analyses included in the umbrella review were appraised as having very low certainty and the other two as having low certainty.

CONCLUSION

The literature appraisal, in conjunction with risk assessment of the Omicron variant, side-effects and acceptability to HCWs, along with the precautionary principle, supported maintaining the current policy guided by PCRA rather than adopting a more rigid approach. Well-designed prospective multi-centre trials, with systematic attention to the diversity of healthcare settings, risk levels and equity concerns are needed to support future masking policies.

Contact dermatitis caused by prevention measures during the COVID-19 pandemic: a narrative review

Introduction

During the outbreak of Coronavirus disease 2019 (COVID-19), health care workers wore personal protective equipment including masks, gloves and goggles for a long time. In order to reduce the transmission routes of the virus, public places were sprayed with disinfectant. Moreover, the body, hands and clothing were frequently disinfected and washed for hygiene purposes. Studies have shown that these practices could easily irritate the skin and damage the skin barrier. Long-term irritation or exposure to allergens may lead to the occurrence of contact dermatitis (CD).

Methods

Subject headings were searched via the National Library of Medicine (PubMed) and web of science databases: COVID-19; contact dermatitis; adverse skin reaction; PPE; dermatitis; mask; glory; hand hygiene, disinfection; face shield; goggle; protect cloth. A total of 246 and 646 articles were retrieved from the two databases, respectively. 402 articles remained after removing duplicates. Reviews, non-English articles, articles that could not be accessed to read or did not conform to our topic were excluded. Finally, a total of 32 cross-sectional studies, 9 case reports and 2 randomized controlled trials were included.

Discussion

This article reviews reports of CD caused by various prevention and hygiene measures during the COVID-19 pandemic. The amount of skin damage caused by COVID-19 prevention measures could be decreased by improved education about skin management.

Risk and protective factors for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among healthcare workers: A test-negative case-control study in Québec, Canada

OBJECTIVES

In Québec, Canada, we evaluated the risk of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection associated with (1) the demographic and employment characteristics among healthcare workers (HCWs) and (2) the workplace and household exposures and the infection prevention and control (IPC) measures among patient-facing HCWs.

DESIGN

Test-negative case-control study.

SETTING

Provincial health system.

PARTICIPANTS

HCWs with PCR-confirmed coronavirus disease 2019 (COVID-19) diagnosed between November 15, 2020, and May 29, 2021 (ie, cases), were compared to HCWs with compatible symptoms who tested negative during the same period (ie, controls).

METHODS

Adjusted odds ratios (aORs) of infection were estimated using regression logistic models evaluating demographic and employment characteristics (all 4,919 cases and 4,803 controls) or household and workplace exposures and IPC measures (2,046 patient-facing cases and 1,362 controls).

RESULTS

COVID-19 risk was associated with working as housekeeping staff (aOR, 3.6), as a patient-support assistant (aOR, 1.9), and as nursing staff (aOR, 1.4), compared to administrative staff. Other risk factors included being unexperienced (aOR, 1.5) and working in private seniors' homes (aOR, 2.1) or long-term care facilities (aOR, 1.5), compared to acute-care hospitals. Among patient-facing HCWs, exposure to a household contact was reported by 9% of cases and was associated with the highest risk of infection (aOR, 7.8). Most infections were likely attributable to more frequent exposure to infected patients (aOR, 2.7) and coworkers (aOR, 2.2). Wearing an N95 respirator during contacts with COVID-19 patients (aOR, 0.7) and vaccination (aOR, 0.2) were the measures associated with risk reduction.

CONCLUSION

In the context of the everchanging SARS-CoV-2 virus with increasing transmissibility, measures to ensure HCW protection, including vaccination and respiratory protection, and patient safety will require ongoing evaluation.

Major Update: Masks for Prevention of SARS-CoV-2 in Health Care and Community Settings-Final Update of a Living, Rapid Review

BACKGROUND

Optimal use of masks for preventing COVID-19 is unclear.

PURPOSE

To update an evidence synthesis on N95, surgical, and cloth mask effectiveness in community and health care settings for preventing SARS-CoV-2 infection.

DATA SOURCES

MEDLINE, EMBASE, medRxiv (3 June 2022 to 2 January 2023), and reference lists.

STUDY SELECTION

Randomized trials of interventions to increase mask use and risk for SARS-CoV-2 infection and observational studies of mask use that controlled for potential confounders.

DATA EXTRACTION

Two investigators sequentially abstracted study data and rated quality.

DATA SYNTHESIS

Three randomized trials and 21 observational studies were included. In community settings, mask use may be associated with a small reduced risk for SARS-CoV-2 infection versus no mask use, on the basis of 2 randomized trials and 7 observational studies. In routine patient care settings, surgical masks and N95 respirators may be associated with similar risk for SARS-CoV-2 infection, on the basis of 1 new randomized trial with some imprecision and 4 observational studies. Evidence from observational studies was insufficient to evaluate other mask comparisons due to methodological limitations and inconsistency.

LIMITATION

Few randomized trials, studies had methodological limitations and some imprecision, suboptimal adherence and pragmatic aspects of randomized trials potentially attenuated benefits, very limited evidence on harms, uncertain applicability to Omicron variant predominant era, meta-analysis not done due to heterogeneity, unable to formally assess for publication bias, and restricted to English-language articles.

CONCLUSION

Updated evidence suggests that masks may be associated with a small reduction in risk for SARS-CoV-2 infection in community settings. Surgical masks and N95 respirators may be associated with similar infection risk in routine patient care settings, but a beneficial effect of N95 respirators cannot be ruled out.

PRIMARY FUNDING SOURCE

None.

Measurement of SARS-CoV-2 in air and on surfaces in Scottish hospitals

BACKGROUND

There are still uncertainties in our knowledge of the amount of SARS-CoV-2 virus present in the environment - where it can be found, and potential exposure determinants - limiting our ability to effectively model and compare interventions for risk management.

AIM

This study measured SARS-CoV-2 in three hospitals in Scotland on surfaces and in air, alongside ventilation and patient care activities.

METHODS

Air sampling at 200 L/min for 20 min and surface sampling were performed in two wards designated to treat COVID-19-positive patients and two non-COVID-19 wards across three hospitals in November and December 2020.

FINDINGS

Detectable samples of SARS-CoV-2 were found in COVID-19 treatment wards but not in non-COVID-19 wards. Most samples were below assay detection limits, but maximum concentrations reached 1.7×10³ genomic copies/m³ in air and 1.9×10⁴ copies per surface swab (3.2×10² copies/cm² for surface loading). The estimated geometric mean air concentration (geometric standard deviation) across all hospitals was 0.41 (71) genomic copies/m³ and the corresponding values for surface contamination were 2.9 (29) copies/swab. SARS-CoV-2 RNA was found in non-patient areas (patient/visitor waiting rooms and personal protective equipment changing areas) associated with COVID-19 treatment wards.

CONCLUSION

Non-patient areas of the hospital may pose risks for infection transmission and further attention should be paid to these areas. Standardization of sampling methods will improve understanding of levels of environmental contamination. The pandemic has demonstrated a need to review and act upon the challenges of older hospital buildings meeting current ventilation guidance.

Spread of viruses, which measures are the most apt to control COVID-19?

The persistent debate about the modes of transmission of SARS-CoV2 and preventive measures has illustrated the limits of our knowledge regarding the measures to be implemented in the face of viral risk. Past and present (pandemic-related) scientific data underline the complexity of the phenomenon and its variability over time. Several factors contribute to the risk of transmission, starting with incidence in the general population (i.e., colonization pressure) and herd immunity. Other major factors include intensity of symptoms, interactions with the reservoir (proximity and duration of contact), the specific characteristics of the virus(es) involved, and a number of unpredictable elements (humidity, temperature, ventilation…). In this review, we will emphasize the difficulty of "standardizing" the situations that might explain the discrepancies found in the literature. We will show that the airborne route remains the main mode of transmission. Regarding preventive measures of prevention, while vaccination remains the cornerstone of the fight against viral outbreaks, we will remind the reader that wearing a mask is the main barrier measure and that the choice of type of mask depends on the risk situations. Finally, we believe that the recent pandemic should induce us in the future to modify our recommendations by adapting our measures in hospitals, not to the pathogen concerned, which is currently the case, but rather to the type of at-risk situation.

The Spread of Exhaled Air and Aerosols during Physical Exercise

Physical exercise demonstrates a special case of aerosol emission due to its associated elevated breathing rate. This can lead to a faster spread of airborne viruses and respiratory diseases. Therefore, this study investigates cross-infection risk during training. Twelve human subjects exercised on a cycle ergometer under three mask scenarios: no mask, surgical mask, and FFP2 mask. The emitted aerosols were measured in a grey room with a measurement setup equipped with an optical particle sensor. The spread of expired air was qualitatively and quantitatively assessed using schlieren imaging. Moreover, user satisfaction surveys were conducted to evaluate the comfort of wearing face masks during training. The results indicated that both surgical and FFP2 masks significantly reduced particles emission with a reduction efficiency of 87.1% and 91.3% of all particle sizes, respectively. However, compared to surgical masks, FFP2 masks provided a nearly tenfold greater reduction of the particle size range with long residence time in the air (0.3-0.5 μm). Furthermore, the investigated masks reduced exhalation spreading distances to less than 0.15 m and 0.1 m in the case of the surgical mask and FFP2 mask, respectively. User satisfaction solely differed with respect to perceived dyspnea between no mask and FFP2 mask conditions.

Development of a customized mask retainer for improving the fit performance of surgical masks

This study introduces a customized mask retainer to improve the fit performance of surgical masks using various advanced digital techniques. The participant's 3D face scans with and without a surgical mask were taken by using a smartphone. The mask retainer was designed using the 3D face scan data based on the facial anthropometric landmarks. The fitting was inspected and adjusted using the masked face scan data. The retainer was fabricated using a 3D printer. The effectiveness of the retainer on the augmentation of the fit of the surgical mask was tested according to the Chinese Standard (GB 19083-2010). A questionnaire was used to assess the effect of wearing surgical masks with and without retainers and N95 respirators on subjective perception of discomfort. The effectiveness test of the retainer on the augmentation of the fit performance showed a better than 25-fold increase in the overall fit factor, meeting the fit requirement for KN95 respirators in China. The subjective perception of discomfort of wearing N95 was significantly greater than surgical mask with and without retainers. The fit factor results indicated that by using the retainer, the overall fit factors and that of each exercise significantly increased compared to that of the group with the surgical mask alone. And compared with N95, the surgical mask with the retainer significant improved comfort. The surgical mask with the retainer can provide an alternative of personal protective equipment for healthcare workers.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial

BACKGROUND

It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators.

OBJECTIVE

To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care.

DESIGN

Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643).

SETTING

29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022.

PARTICIPANTS

1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19.

INTERVENTION

Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site.

MEASUREMENTS

The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test.

RESULTS

In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group.

LIMITATION

Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination.

CONCLUSION

Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

A critical review on the role of leakages in the facemask protection against SARS-CoV-2 infection with consideration of vaccination and virus variants

The protection provided by facemasks has been extensively investigated since the beginning of the SARS-CoV-2 outbreak, focusing mostly on the filtration efficiency of filter media for filtering face pieces (FFP), surgical masks, and cloth masks. However, faceseal leakage is a major contributor to the number of potentially infectious airborne droplets entering the respiratory system of a susceptible individual. The identification of leaking spots and the quantification of leaking flows are crucial to estimate the protection provided by facemasks. This study presents a critical review on the measurement and calculation of facemask leakages and a quantitative analysis of their role in the risk of SARS-CoV-2 infection. It shows that the pairing between the mask dimensions and the wearer's face is essential to improve protection efficiency, especially for FFP2 masks, and summarizes the most common leaking spots at the interface between the mask and the wearer's face. Leakage is a crucial factor in the calculation of the protection provided by facemasks and outweighs the filtration performances. The fit factors measured among mask users were summarized for different types of face protection. The reviewed data were integrated into a computational model to compare the mitigation impact of facemasks with vaccination with consideration of new variants of SARS-CoV-2. Combining a high adoption rate of facemasks and a high vaccination rate is crucial to efficiently control the spread of highly infectious variants.

COVID-19 Rapid Antigen Tests: Bibliometric Analysis of the Scientific Literature

As the COVID-19 pandemic continues to disrupt health systems worldwide, conducting Rapid Antigen Testing (RAT) at specified intervals has become an essential part of many people's lives around the world. We identified and analyzed the academic literature on COVID-19 RAT. The Web of Science electronic database was queried on 6 July 2022 to find relevant publications. Publication and citation data were retrieved directly from the database. VOSviewer, a bibliometric software, was then used to relate these data to the semantic content from the titles, abstracts, and keywords. The analysis was based on data from 1000 publications. The most productive authors were from Japan and the United States, led by Dr. Koji Nakamura from Japan (n = 10, 1.0%). The most academically productive countries were in the North America, Europe and Asia, led by the United States of America (n = 266, 26.6%). Sensitivity (n = 32, 3.2%) and specificity (n = 23, 2.3%) were among the most frequently recurring author keywords. Regarding sampling methods, "saliva" (n = 54, 5.4%) was mentioned more frequently than "nasal swab" (n = 32, 3.2%) and "nasopharyngeal swab" (n = 22, 2.2%). Recurring scenarios that required RAT were identified: emergency department, healthcare worker, mass screening, airport, traveler, and workplace. Our bibliometric analysis revealed that COVID-19 RAT has been utilized in a range of studies. RAT results were cross-checked with RT-PCR tests for sensitivity and specificity. These results are consistent with comparable exchanges of methods, results or discussions among laboratorians, authors, institutions and publishers in the involved countries of the world.

Risk of SARS-CoV-2 Acquisition in Health Care Workers According to Cumulative Patient Exposure and Preferred Mask Type

This cohort study compares the risk of infection with SARS-CoV-2 among health care workers by mask preference and level of patient exposure.