WHO Interim Guidance: Advice On The Use Of Masks In The Context Of COVID-19

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Two months before word of the novel coronavirus virus emerged from China, the World Health Organization released a long-awaited 91-page NPI Guidance document for dealing with the next influenza pandemic (see WHO Guidance: Non-pharmaceutical Public Health Measures for Mitigating the Risk and Impact of Epidemic and Pandemic Influenza).

NPIs - or Non-Pharmaceutical Interventions - are those actions (apart from taking vaccines & antivirals) that individuals and communities can do to help slow the spread of an infectious disease.

They won't stop a pandemic, but they can help reduce its impact, by `flattening the epi curve '. This would make for longer, but more manageable, pandemic waves. The new WHO guidance divided NPIs into four broad categories; Personal Protection, Environmental Measures, Social Distancing Measures & Travel Related Measures.

For those interested in what is now ancient history, I wrote lengthy blogs on each of these sections last November:

The WHO Pandemic Influenza NPI Guidance : Travel Measures

The WHO NPI Guidance : Environmental Measures

The WHO NPI Guidance : Social Distancing

The WHO NPI Guidance : Personal Protection

While the advice was presented as being `evidence based', I questioned whether some of their recommendations - particularly those advocating against travel bans and quarantines, early school closures, and the wearing of masks by the public - would be fully embraced during a severe pandemic.

WHO NPI Recommendations

Somewhat ironically, contact tracing is now among the WHO's strongest recommendations, and as long as we call them `lockdowns', quarantines - even of entire cities - are now considered reasonable as well.

History will show that other measures discouraged by the WHO NPI guidelines, including early school closures, travel bans, and even border closures, have helped to slow the spread of COVID-19.

And while the jury is still out, there is growing evidence that the wearing of masks by the general public, may also be beneficial in reducing the spread of the virus.

Note: Given the extreme shortage of medical masks around the globe (surgical & N95) - and the need to reserve those for HCWs - for this discussion we are mainly talking about non-medical cloth masks or face-coverings.

Their use has long been discouraged by the WHO, including in their NPI recommendations from last year, and more recently in the following COVID-19 advice:

While the science behind using face coverings in public is less than robust, there is enough anecdotal evidence that nearly every Asian nation now recommends (or requires) the wearing of masks outside the home, and our own CDC has recently recommended the practice for Americans (see The CDC's Cloth Face Cover Recommendations).

Last January, in The Man In The Ironed Mask (Revisited), we looked at the studies (both pro and con) on the practice, and while their effectiveness appears fairly limited, my conclusion is wearing one probably beats not wearing one at all.

Overnight the WHO released a new, revised 5-page PDF interim guidance document on the use of masks during this COVID-19 pandemic. While still not recommending the wearing of masks or face coverings by the general public, they do offer Advice to decision makers on the use of masks by healthy people in community settings.

I've only posted the link and a few excerpts, so by all means download and read the full document.

Advice on the use of masks in the context of COVID-19

6 April 2020
Download (650.3 kB)

Overview

This document provides advice on the use of masks in communities, during home care, and in health care settings in areas that have reported cases of COVID-19. It is intended for individuals in the community, public health and infection prevention and control (IPC) professionals, health care managers, health care workers (HCWs), and community health workers. This updated version includes a section on Advice to decision makers on the use of masks for healthy people in community settings.

(EXCERPT)

Community settings

Studies of influenza, influenza-like illness, and human coronaviruses provide evidence that the use of a medical mask can prevent the spread of infectious droplets from an infected person to someone else and potential contamination of the environment by these droplets. 13

There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure. 14-23

However, there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19.

(SNIP)

Advice to decision makers on the use of masks for healthy people in community settings

As described above, the wide use of masks by healthy people in the community setting is not supported by current evidence and carries uncertainties and critical risks. WHO offers the following advice to decision makers so they apply a risk-based approach.

(SNIP)

However, the following potential risks should be carefully taken into account in any decision-making process:
self-contamination that can occur by touching and reusing contaminated mask
depending on type of mask used, potential breathing difficulties
false sense of security, leading to potentially less adherence to other preventive measures such as physical distancing and hand hygiene
diversion of mask supplies and consequent shortage of mask for health care workers
diversion of resources from effective public health measures, such as hand hygiene
(Continue . . . )

Even given the lack of scientific evidence of it protecting the wearer, I honestly don't understand the rationale behind their reluctance to endorse cloth masks or face coverings, given what we know about asymptomatic transmission of COVID-19.

There is strong evidence to suggest that face masks can limit the spread of a respiratory virus when worn by someone who is infected (see Respiratory virus shedding in exhaled breath and efficacy of face masks).

The list of `risks' seems tortured to within an inch of its life.

The `self-contamination' concerns ignores that a person's skin or clothing will also be contaminated. The `shortage' for HCWs only applies if people are using medical masks, and `the false sense of security' argument can be overcome easily by proper messaging.

Instead of clinging to advice they know will be ignored by half the world, it would make far more sense to say:

`Cloth masks aren't proven to be effective in preventing infection - but as long as you wash your hands often and maintain social distancing - if you want to wear one in public, it probably won't hurt . . . and it might actually help a little'.

What people want right now is simple, direct, and easy to follow advice. And an acknowledgement that their concerns are legitimate, as are their desires to do something tangible to protect themselves.