Executive Summary

Version 4.0 Infection prevention and control in the context of coronavirus disease 2019 (COVID-19): a living guideline Updated chapter: Mask use. Part 2: Community settings

About this guideline

The Infection prevention and control in the context of coronavirus disease 2019 (COVID-19): a living guideline consolidates infection prevention and control (IPC) technical guidance developed and published during the COVID-19 pandemic into evidenceinformed recommendations for IPC. Part 1 presents IPC recommendations in the context of health care settings, while Part 2 presents recommendations for community settings. The methodology section describes the methodological approach used to develop the guideline, including a glossary. An annex is included with evidence tables for mask use in the health care and community settings and mask use by children. The living guideline is written, disseminated and updated on an online platform (MAGICapp). It has a user-friendly format and easy-to-navigate structure that accommodates dynamically updated evidence and recommendations. This structure focuses on what is new while keeping existing recommendations updated within the guideline.

This living guideline considers the current and evolving epidemiological trends for COVID-19 and the emergence of new variants of concern (VoC), including Omicron and its sublineages, and factors such as population immunity, availability and uptake of vaccines, and other contextual factors of the COVID-19 pandemic.

The target audiences of these guidelines are policy- and decision-makers, public health professionals, IPC professionals at the national, subnational and facility levels, health care facility administrators, managers, and other health workers.

Context

Countries are facing varying degrees of impact from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Considering the global COVID-19 epidemiological situation, the evolution and unpredictability of the virus, and the effect of current and future SARSCoV-2 VoC, including descendent lineages of these variants and concurrent circulation of other respiratory viruses, including influenza, a combination of mitigation methods are required to reduce the impact of the COVID-19 pandemic [1]. Factors such as the intensity of SARS-CoV-2 circulation, vaccination coverage, population immunity to SARS-CoV-2, health systems’ responsiveness capacity, and adjustability of public health and social measures (PHSM) influence viral circulation and epidemiological situations worldwide [3][4] National policies should be strengthened and implemented to encourage the maintenance of IPC measures in healthcare facilities and PHSM for COVID-19 in community settings based on these and other factors [4][5]. In particular, prior to adjusting PHSM, the local situation should be determined, taking into consideration three main factors: SARS-CoV-2 transmissibility (also in consideration of any emerging variant); the seriousness of COVID-19; and the impact on the health system [65].

Updated recommendations

This version of the guidelines (version 4.0), includes the following recommendations:

1. a strong recommendation for mask use in community settings in higher risk situations;

2. a conditional recommendation to encourage a risk-based approach for mask use in community settings in situations that do not fall within the scope of the strong recommendation;

3. a good practice statement advising individuals with signs and symptoms suggestive of COVID-19 or those who test positive for COVID-19 to wear a medical mask when interacting with others in or outside of one’s household or sharing space with others; and

4. amendment of an existing good practice statement on the implementation of policies to reduce SARS-CoV-2 transmission to promote the revisiting and strengthening of PHSM as new evidence arises.

Understanding the new recommendations

The Guideline Development Group (GDG) considered a combination of current scientific evidence [2] while assessing relative benefits and harms, values and preferences, resource implications, availability, and feasibility issues. The strong and conditional recommendations for mask use in the community complement each other, outlining possible scenarios in which masks may benefit the wearer. As some situations (see strong recommendation) necessitate mask wearing for maximum protection, others (see conditional recommendation) may be better suited for a risk-based approach. PHSM combine measures (for example, physical distancing, mask use, and hand hygiene) to mitigate the impact of SARS-CoV-2 infection.

Updates to prior recommendations

Version 1.0 of the COVID-19 infection prevention and control living guideline: mask use in community settings published in December 2021 [6], provided new guidance on mask use in community settings. This guideline superseded existing advice in Mask use in the context of COVID-19 issued in December 2020 [7]. Version 4.0 of the living guideline is the most recent update on guidance for mask use in the community.

Version 2.0 of the COVID-19 living guideline jointly developed by the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) was published in March 2022 [8]. This version contained updated guidance on mask use in children; Advice on the use of masks for children in the context of COVID-19 was first published in August 2020 as an annex to the document Mask use in the context of COVID-19 [7][9]. Version 2.0 of the living guideline superseded any previous advice on the use of masks for children in the context of COVID-19.

Version 3.0 of the COVID-19 living guideline published in April 2022 [10], provided new guidance on mask use in healthcare settings. This updated guideline superseded any advice on mask use in the health care setting in the context of COVID-19 [10][11][12].

Guideline development

This guideline was developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) processes and Evidence to Decision framework [13] and in accordance with WHO norms and standards for guideline development [14][15].

The composition of the GDG includes experts in IPC, epidemiology, infectious diseases, paediatrics, water, sanitation and hygiene, engineering, aerobiology, and healthcare providers. The groups were balanced according to geographical and gender representation. Different GDGs were convened to address specific settings or populations (see authorship, contributors, and acknowledgements section). A methodologist with expertise in guideline development assisted the GDG in formulating the recommendations. While the GDG takes an individual patient perspective in making recommendations, it also considers resource implications, acceptability, feasibility, equity and human rights. The WHO Quality Assurance of Norms and Standards department helped to identify published rapid systematic reviews for the review process. Where required, WHO staff or commissioned external review teams conducted systematic reviews to address specific questions. Due to the rapidly evolving nature of the pandemic, preprints were included in the evidence synthesis. Additional details are described in the methodology section.

Updates and access

This guideline and its previous versions are available through the WHO website and MAGICapp (online and PDF outputs for readers with limited internet access).