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| Credit NIOSH |
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One of the biggest challenges during the next (presumably influenza) pandemic will be providing adequate PPEs (Personal Protective Equipment) to medical workers and 1st responders; masks, gloves, gowns, eye shields, etc.
A decade ago, during the opening weeks of the 2009 H1N1 pandemic - many hospitals had an inadequate supply of PPEs on hand - and that led to a number of protests (see Nurses Protest Lack Of PPE’s , Report: Nurses File Complaint Over Lack Of PPE).
- In some cases nurses reported they were issued only one N95 mask to be used for an entire 8 hour shift, and told to don it only when in direct contact with a potentially infected patient.
- In other venues, HCWs were issued surgical masks in lieu of N95s, despite the recommendation at the time from the CDC that N95 masks were the preferred level of protection.
Augmenting existing supplies, during a time when every country in the world will be scrambling for their share, won't be easy. Particularly since nearly all of these items are produced outside of the United States.
A lack of PPEs for HCWs could have a serious impact, both in spreading the virus, and in the attrition rate of healthcare personnel due either to illness, or an unwillingness to work without some form of protection.In late 2011 a study published in the journal Infection Control and Hospital Epidemiology showed that the inadequate use of masks by healthcare workers during the opening days of the 2009 pandemic put them at greater risk of contracting the virus (and spreading it to patients).
Fortunately, the virulence of the novel 2009 H1N1 pandemic was less than originally feared. Had it carried a higher mortality rate, the lack of PPEs would have become a much bigger issue.We may not be so lucky during the next influenza pandemic, and over the past decade we've seen a good deal of - often conflicting - research on the relative merits of surgical masks vs. disposable N95 respirators.
- The simple surgical mask has the advantage of being cheap (about 10 cents each), easy to don, and easier to breath through than the N95 respirator.
- N95 respirators are 10 times more expensive, difficult to wear for extended periods of time, must be replaced every few hours, and each individual must be `fit-tested' (see Survival Of The Fit-tested).
For decades, the assumption was that only properly fitted N95 masks protected the wearer, and that surgical masks were only worn by HCWs to protect the patient during invasive procedures. A 2008 NIOSH Science blog called Influenza Pandemic and the Protection of Healthcare Workers with Personal Protective Equipment describes their effectiveness thusly:
Medical masks are not designed or certified to protect the wearer from exposure to airborne hazards. They may offer some limited, as yet largely undefined, protection as a barrier to splashes and large droplets.In the fall of 2009 we looked at one study that found surgical masks to be severely lacking (see A Surgical Mask Strike) while another (see JAMA: Surgical Masks vs N95 Respirators) reported HCWs using surgical masks experienced `noninferior rates of laboratory-confirmed influenza’.
However, because of the loose-fitting design of medical masks and their lack of protective engineering, medical masks are not considered personal protective equipment.
Again in 2010 we saw a study (see Efficacy of Facemasks Vs. Respirators), that suggested that inexpensive medical masks may be more effective than previously thought in protecting against the H1N1 virus.
Other studies have been far less sanguine about the effectiveness of surgical masks in the wearer (see NEJM Perspective: Respiratory Protection For HCWs).If all of this weren't confusing enough, in 2012 another study (see Aerosolized Influenza And PPEs), found that a surgical mask, as normally worn by HCWs, blocked 56.6% of infectious virus particles.
But . . . if you tightly seal the surgical mask against the face (with tape), you can achieve a level of protection approaching that of a well fitted N95 respirator (94.8% versus 99.6%).A poorly fitted N-95 respirator provided little more protection (66.5%) than a loosely fitted surgical mask. Suggesting that it may be more important how you wear a mask - rather than the type.
The above is but a small sampling of the great N95 vs. Surgical Mask debate over the past 10 years.While it may not settle the matter to everyone's satisfaction, we've a new study - published yesterday in JAMA - that suggests there was little practical difference in infection rates between HCWs who wore either type of respiratory PPE over several flu seasons following the pandemic.
The full report is behind a paywall, but the abstract is available (excerpts below) as is a press release from the UT Southwestern Medical Center (also below).I'll return with a brief postscript at the end.
September 3, 2019
N95 Respirators vs Medical Masks for Preventing Influenza Among Health Care PersonnelA Randomized Clinical Trial
Key Points
Question Is the use of N95 respirators or medical masks more effective in preventing influenza infection among outpatient health care personnel in close contact with patients with suspected respiratory illness?
Findings In this pragmatic, cluster randomized clinical trial involving 2862 health care personnel, there was no significant difference in the incidence of laboratory-confirmed influenza among health care personnel with the use of N95 respirators (8.2%) vs medical masks (7.2%).
Meaning As worn by health care personnel in this trial, use of N95 respirators, compared with medical masks, in the outpatient setting resulted in no significant difference in the rates of laboratory-confirmed influenza.
(Continue . . . )
News Release 3-Sep-2019
Surgical masks as good as respirators for flu and respiratory virus protection
UT Southwestern Medical Center
DALLAS - Sept. 3, 2019 - Researchers may finally have an answer in the long-running controversy over whether the common surgical mask is as effective as more expensive respirator-type masks in protecting health care workers from flu and other respiratory viruses.
A study published today in JAMA compared the ubiquitous surgical (or medical) mask, which costs about a dime, to a less commonly used respirator called an N95, which costs around $1. The study reported "no significant difference in the effectiveness" of medical masks vs. N95 respirators for prevention of influenza or other viral respiratory illness.
"This study showed there is no difference in incidence of viral respiratory transmission among health care workers wearing the two types of protection," said Dr. Trish Perl, Chief of UT Southwestern's Division of Infectious Diseases and Geographic Medicine and the report's senior author. "This finding is important from a public policy standpoint because it informs about what should be recommended and what kind of protective apparel should be kept available for outbreaks."(SNIP)
The new study was performed at multiple medical settings in seven cities around the country, including Houston, Denver, Washington, and New York, by researchers at the University of Texas, the CDC, Johns Hopkins University, the University of Colorado, Children's Hospital Colorado, the University of Massachusetts, the University of Florida, and several Department of Veterans Affairs hospitals. Researchers collected data during four flu seasons between 2011 and 2015, examining the incidence of flu and acute respiratory illnesses in the almost 2,400 health care workers who completed the study.
The project was funded by the CDC, the Veterans Health Administration, and the Biomedical Advanced Research and Development Authority (BARDA), which is part of the U.S. Health and Human Services Department and was founded in the years after Sept. 11, 2001, to help secure the nation against biological and other threats.
"It was a huge and important study - the largest ever done on this issue in North America," Dr. Perl said.
(Continue . . . )
While I'm somewhat comforted by these findings, recent history suggests this may not be the last word on the subject. And its conclusions - which are based on H1N1 and H3N2 influenza exposure - may not extend to novel avian flu (H5N6, H7N9, etc.), MERS, Nipah, or other more exotic respiratory viruses.
But during the next severe pandemic the question of which type of respiratory protection is best for HCWs may quickly become moot, as the supply of N95s could run out, leaving surgical masks as the only viable option.
Regardless of mask availability, Health care workers will have plenty of other opportunities to exposed outside of their work environment. In which case the wearing of surgical masks could help reduce forward transmission.Hopefully we'll have a much better handle on all of this after the next pandemic, and will be better prepared for the pandemic that follows.
