Children's Hospital Colorado

Multi-Year Study Compares Surgical Masks to Respirators for Flu and Respiratory Virus Protection

Children's Hospital Colorado | septiembre 23, 2019

Is a respirator or medical mask better at protecting healthcare workers from the flu?

Researchers suggest the common surgical mask is as effective as more expensive respirator-type masks in protecting healthcare workers from flu and other respiratory viruses.

A study published Sept. 3 in the Journal of the American Medical Association (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.

“It’s hugely beneficial for us to know that there is no difference in the incidence of viral respiratory transmission among healthcare providers wearing the two types of protection,” said Christine Nyquist, MD, MSPH, medical director of Infection Prevention and Control & Occupational Health at Children’s Hospital Colorado and site lead investigator.

“This study was the first and largest multi-year study that assessed the safety of health providers caring for children during the busy winter-time respiratory season. Our top goal at Children’s Hospital Colorado is to keep both our patients and care providers safe and healthy.”

Flu risk for healthcare workers

Medical personnel – in particular nurses, doctors and others with direct patient contact – are at risk when treating patients with contagious diseases such as influenza (flu).

A large study conducted in a New York hospital system after the 2009 outbreak of H1N1, or swine flu, found almost 30% of health care workers in emergency departments contracted the disease themselves.

During that pandemic, the U.S. Centers for Disease Control and Prevention (CDC) recommended using the tighter-fitting N95 respirators, designed to fit closely over the nose and mouth and filter at least 95% of airborne particles, rather than the looser-fitting surgical masks routinely worn by health care workers. But some facilities had trouble replenishing N95s as supplies were used.

In addition, there are concerns healthcare workers might be less vigilant about wearing the N95 respirators since many perceive them to be less comfortable than medical masks. Compared to masks, respirators can make breathing more difficult and are much warmer on the user's face.

Earlier clinical studies comparing the masks and respirators yielded mixed results, said Dr. Nyquist, also a professor of pediatrics in the Sections of Infectious Disease and Epidemiology at CU School of Medicine, Anschutz Medical Campus.

This study was performed at multiple medical settings in seven cities around the country, including Denver, Houston, Washington and New York, by researchers at the University of Colorado, Children’s Hospital Colorado, the University of Texas, the US CDC, the Veterans Affairs Administration, Johns Hopkins, the University of Massachusetts and the University of Florida. 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 healthcare workers who completed the study. Denver locations included Children’s Colorado, Denver Health and the Eastern Colorado VA Eastern Colorado Health Care System.

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.

Significance for influenza planning

“It was a huge and important study – the largest ever done on this issue in North America,” said Dr. Trish Perl, chief of UT Southwestern’s Division of Infectious Diseases and Geographic Medicine and the report’s senior author.

In the end, 207 laboratory-confirmed influenza infections occurred in the N95 groups versus 193 among medical mask wearers, according to the report. In addition, there were 2,734 cases of influenza-like symptoms, laboratory-confirmed respiratory illnesses, and acute or laboratory-detected respiratory infections (where the worker may not have felt ill) in the N95 groups, compared with 3,039 such events among medical mask wearers.

“The takeaway is that this study shows one type of protective equipment is not superior to the other,” Perl said. “Facilities have several options to provide protection to their staff – which include surgical masks – and can feel that staff are protected from seasonal influenza. Our study supports that in the outpatient setting there was no difference between the tested protections.”

Dr. Nyquist said she expects more studies to arise from the data collected in this report; she now plans to investigate whether healthcare providers caring for children acquire more respiratory infections than healthcare providers caring for adults.

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