COVID – Understanding Recommendation for Face Masks

June 28, 2020

There is a tremendous amount of misinformation regarding use of face masks to decrease transmission of COVID. As with many aspects of this pandemic, mask use has become politicized. It is essential to understand that all science, including public health science, is evolving – which means information changes as data is accumulated. This means that recommendations change as new information becomes available. A new virus with limited to no prior information about it adds to the uncertainty. Understandably, all this uncertainty has caused many Americans to question the validity of recommendations to help decrease transmission of COVID – even the seriousness of this virus has been called into question. For example, initially there was a significant shortage of masks for frontline workers, which was why authorities were reluctant to recommend masks to the general public. It is understandable that people may look back at this old advice and not know what to believe now. I think we should trust the public health scientists and realize their recommendations may change as better data becomes available.

 

What We Know

COVID is primarily transmitted person-to-person via respiratory droplets. Washing your hands, staying away from people (social distancing) and decreasing germ transmission will all help to decrease spread. While high quality research regarding mask use is limited, all of the data to date supports that wearing masks while in public is a key public health measure to decrease viral spread.

 

Mask Effectiveness

The gold standard N95 mask is 95% effective at preventing inhalation of viral particles.  These masks are still best for frontline workers in high risk settings where aerosolization of viral particles occurs at a higher rate than among the general population. Surgical masks are less effective and cloth face coverings even less effective when compared to these N95 masks. However it is essential to understand that even a 50% reduction in viral transmission is statistically important.  For the general public, the reason to wear a face mask is to help protect others from you when you cough, sneeze or even talk and spray viral droplets into the air.  Many people who become infected can unknowingly spread COVID because they have few or no symptoms.  Wearing a mask is showing respect for others and is your way of helping lessen the spread of the virus. If we can slow down transmission then hospitals and medical care facilities will not get overwhelmed and will have a fighting chance to treat people.

 

Masks and Low Oxygen Levels

Masks absolutely do NOT decrease oxygen levels. As healthcare workers, we often wear masks all day in the hospital. The masks are designed to be breathed through and there is no evidence that low oxygen levels occur. There is also no evidence that cloth masks increase build-up of carbon dioxide – although there is some evidence that prolonged use of N95 masks in people with preexisting lung disease could cause some build-up of carbon dioxide. People with preexisting lung problems should discuss mask wearing concerns with their health care providers. There is absolutely no scientific evidence that mask wearing or physical distancing weakens the immune system.

 

What Should You Do?

Decreasing the severity of the pandemic is about statistics. To avoid this infection 100% you must isolate yourself completely, which is unrealistic for most people. In fact, doing this is not practical or mentally helpful for the vast majority of people. The next steps are to do things which limit the likelihood of spread from person-to-person. These things include hand-washing, social distancing and mask wearing. The further away you are from an infected person, the less likely you are to get the virus. Six feet is better than two feet (and 12 feet is probably better than six feet). At some point the distance away becomes statistically meaningless. Unfortunately, there is no absolute correct number. Airflow (indoor, outdoor, ventilation, wind, etc), temperature, humidity, viral load being produced by the infected person and the susceptibility of the uninfected person all play a role in how far apart you need to be. Masks are not 100% effective, but wearing a mask does decrease the risk of viral spread. Public health professionals believe that hand-washing, wearing a mask and social distancing are the keys to controlling the first wave and diminishing or avoiding subsequent waves of the virus. Mask wearing allows us to open the economy up faster. Not wearing a mask around others only worsens the pandemic, leads to more disease, and worsens the economic effects.

 

PLEASE wear a mask in public.