By Betsy Todd, MPH, RN, nurse epidemiologist and AJN clinical editor. Published. March 6; updated March 12.

Times are uncertain. We don’t know how the spread of the new coronavirus will play out, or what parts of the country will be affected next. Many people continue to insist that wearing a mask in public places is “added insurance” against infection. But the reasons for NOT wearing a face mask far outweigh the purported benefit of keeping your nose and mouth covered when you’re out and about.

First, some background.

Health care workers use two main kinds of mouth and nose protection: either a regular surgical face mask, or an N95 respirator.

The purpose of a surgical mask is to prevent the wearer’s respiratory secretions from contaminating other people or surfaces. This is an example of “source control” in preventing infections. It is the reason the surgical team wears masks during operations and other invasive procedures.

N95 respirators look very much like face masks. They are designed to protect the wearer from inhaling hazardous particles (infectious agents, dust, etc.). Health care workers wear these when caring for people with COVID-19 or other serious respiratory infections.

But at least a face mask provides a physical barrier. Why shouldn’t I wear one?

Some have suggested that at least wearing a face mask provides a reminder not to touch your face. But there are several reasons why donning a face mask is a bad idea for most people.

  • Used incorrectly, face masks won’t protect you. They can actually increase your risk of infection. After only a short time in use, the mask becomes slightly damp from your breath. When you touch your fingers to the mask—thoughtlessly, or to scratch your nose or readjust the mask—organisms on your hands can travel through the moist mask to your face.
  • Most masks are used incorrectly outside of (and unfortunately, sometimes inside) health care settings. Face masks need to be donned and doffed with care, and immediately discarded after use. You’ve seen people who pull down their face masks and wear them hanging from their neck? They have thoroughly contaminated their neck and upper chest. Don’t hug them. And don’t let them provide patient care without first discarding that dirty mask and changing their shirt.
  • Face masks can give people a false sense of security. For protection from infection, face masks need to be worn along with goggles or face shields. When droplets containing respiratory virus contact the eye, they can travel to the respiratory system through the nasolacrimal duct. In addition, many who wear masks often then forego much more critical personal protection measures, such as hand hygiene.
  • There is a growing worldwide shortage of all personal protection gear, and prices have soared. The cost of face masks has increased sixfold, and N95 respirators have tripled in price. The WHO has stated that “rising demand, panic buying, hoarding and misuse is putting lives at risk from the new coronavirus and other infectious diseases.” Health care workers are far more closely and repeatedly exposed to infection than is the person walking down the street or riding the bus. Unprotected health care workers can spread infection. And when they are known to have been exposed to this coronavirus or certain other infectious diseases, they will be furloughed—and that means fewer workers available to take care of us when we need them.

So who should wear face masks?

The CDC and WHO recommendations are very clear: wear a mask if you are coughing or sneezing, or if you are a person caring for someone with suspected or confirmed COVID-19. The WHO adds that careful hand hygiene must always be a part of face mask use, and that there is “no evidence that they [masks] protect people who are not sick.”

(UPDATE: On March 11, the CDC released new recommendations for mask use when caring for people known or suspected to have COVID-19. The CDC is now placing greater emphasis on using regular surgical masks in lieu of N95s. See our upcoming March 13th post for more detailed information.)

Also listen to a Nursing Center podcast, “COVID-19: What Nurses Need to Know about Personal Protective Equipment (PPE),” here.