When Should I Wear a Mask to Protect Against COVID-19? What Kind of Mask Is Best?

Chief Medical Epidemiologist Mini Kamboj

Chief Medical Epidemiologist Mini Kamboj

Getting vaccinated is the best way to protect yourself against COVID-19, but even people who have been fully vaccinated may need to wear a mask for maximum protection against the highly contagious Delta variant. Mini Kamboj, Chief Medical Epidemiologist at Memorial Sloan Kettering Cancer Center, answers questions about what kind of mask you need and when to wear one.

Why would I need to wear a mask if I’ve been vaccinated?

Vaccines are extremely effective at protecting you against severe illness and hospitalization. They also reduce the spread of COVID-19.

But as of October 12, about 56% of Americans have been fully vaccinated against COVID-19, which means tens of millions of people are still not vaccinated. When a lot of people are unvaccinated, COVID-19 can continue to spread, including to those who are vaccinated (which is called a breakthrough infection).

In addition, the vaccine’s protection may decrease after six months, which is why federal health officials now recommend certain groups of people get a booster shot. People with a severely weakened immune system also need an additional dose to strengthen their defenses against COVID-19.

Masks offer an additional tool to reduce the spread of COVID-19. They protect you from getting infected and passing the virus to people around you.

COVID-19 Vaccine Information for Patients
Learn what you need to know about the COVID-19 vaccines if you are an MSK patient.
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Who should wear a mask — and in what situations?

First and foremost, you should follow the rules and guidance in your community for situations including businesses, schools, transportation hubs, and hospitals. At MSK, we require that people wear masks in all shared indoor clinical and nonclinical spaces.

If you are fully vaccinated and do not have a weakened immune system (called immunocompromised):

If you are immunocompromised, you may not be fully protected even if you are vaccinated. Because of that, you should act as you did before you were vaccinated and:

  • Wear a mask when indoors in public places
  • Stay at least six feet apart from people who don’t live in your household
  • Wash your hands frequently for at least 20 seconds
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What mask should I wear? Should I wear an N95 or is a cloth mask good enough?

It is sufficient to wear a cloth mask with two or more layers of breathable fabric. Specialized masks — like N95 or KN95 — are not necessary for anybody but healthcare workers.

The most important thing about a mask is that it fits snugly. It should completely cover your mouth, and should have a wire so that it can bend around the bridge of your nose. It should also have a tight fit around the sides of your face.

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When will we be able to stop wearing masks completely?

It’s difficult to say. We all need to continue to behave safely, and we need more people to get vaccinated so the virus is no longer spreading easily from person to person. That’s when we can feel safe again.


October 14, 2021

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