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CommentaryCovid-19 EpidemicPreventive MedicinePrimary Care

Covid-19: Masks, Hygiene, Distance Work. Updated Behavior and Risk Advice

Now THIS is a mask (Dr. Kanner N95 sprayer protection)

Massachusetts is doing well with the Covid-19 infection, but we must remain vigilant if our gains and relative safety are to be maintained. If we need any external motivation, look at the explosive infections in multiple southern states in the past 10 days.

Continuing with the self-protective behaviors that we have practiced since March is critical to our success. We all know the basics and more. Here are a few quick reminders and advice, in response to many questions received.

Wear your mask

  • Whenever you go out and cannot be sure of keeping social distance.
  • Cloth masks or surgical masks are fine in general to protect others around you.
  • The masks must cover your mouth and nose.
  • Cloth and surgical masks mainly serve to protect others from possible infection from your exhalations, though they also provide meaningful protection to you in low-risk settings.

Wash your hands frequently

  • Wash carefully for at least 20 seconds.
  • Wash your hands whenever you open packages or bring home food.
  • Use hand sanitizer when hand washing is needed and soap and water are not available.

Wash your face as well

  • When you remove your face mask you must afterwards wash your hands and should also wash your face. That takes just a few additional seconds.
  • The outside of the mask is presumed to be contaminated after airborne exposure. The same is true of your face.
  • So, wash your hands and face whenever you return from a trip to a grocery store or comparable low-risk airborne exposure.

Maintain social distance

  • Six feet minimum, always with a mask if indoors and in general if outdoors as well.
  • With familiarity people tend to creep closer. Pay attention.

Outdoors is almost always safe

  • Thank God for summer. It is really hard to pass the virus in outdoor settings.
  • Walking and exercising outdoors are healthy. Wear your mask if you are likely to encounter other exercisers at close distance, and otherwise just keep it handy.
  • If you are entertaining a small group outdoors at home, guests should still separate by 6 ft and in general wear masks.
  • But if you are entertaining outside and you want to forgo masks, we believe more distance (8-10 ft) is meaningfully safer. (We are not aware of hard data on this issue.)

Brief shopping trips are low risk, maybe outdoor restaurants

  • Shopping at a supermarket with one-way aisles and spacing and masked staff has become a relatively safe activity. I observe Costco and BJ’s and others have instituted comparable safeguards. You obviously wear your mask. And wash hands and face when home.
  • Outdoor restaurant dining may prove to be low-risk. With careful table spacing, this should be safe. However, we have only a few weeks’ experience with outdoor restaurants, compared with several months’ with supermarkets, so caution seems appropriate.

Yes, you can allow cleaners and plumbers into your home

  • You can safely allow service-people and house cleaners into your home, providing they are practicing the same self-care procedures and that you distance yourselves while they are there.
  • Service-persons should confirm that they are healthy so far as they know. They should clearly wear masks and put on disposable gloves when they arrive.
  • You can occupy other space while the repairs are done. You might stay out of the room in which they worked (say the kitchen) for an hour afterward and leave the windows open to maximize air exchange.
  • Household cleaners should also confirm they are apparently healthy and with no known exposures, and wear masks and gloves. You can similarly leave windows open in the house to maximize air exchange, and occupy rooms other than those they are cleaning while they are there.
  • At this point, with distancing and masks and apparently uninfected service-people, you should be fine. This will help you achieve some normality in your life, not to mention the service-people’s. As well as to get that dishwasher working again.

But lingering with others indoors remains high risk

  • Gathering in a living room with friends, even with normal masks, or going to an indoors restaurant, is high risk. Our only patient with new Covid-19 in the past two weeks contracted it in a restaurant in a state where indoor dining was allowed.
  • Normal cloth or surgical masks do not provide you realistic protection from Covid-19 infection in those high-risk settings. Only more aggressive PPE including N95 respirator masks really reduces the risk inside.
  • Consequently, it is also unlikely that indoor theater and concerts will return anytime soon.

This is our new normal

  • Covid-19 is not going away in 2020. We have all adapted reasonably well. These safety procedures (hygiene, masks, distancing) work to keep us safe, with which many normal activities are low-risk. We can still socialize within these constraints.
  • Please stay vigilant. It is for your protection and our protection together.


  • Norma L Lane says:

    Dr. Kanner, This is very useful information. Thank you again.

  • David Goldsmith says:

    What about KN95 masks? If not defective, it seems that they should be approximately as good as N95 masks.

    I bought some KN95 masks from Andrews Pharmacy in Wellesley.

    I always wear a KN95 mask under a very nice looking, custom-fitted cloth mask sewn by my wife Marcy.


    • DrKanner says:

      I believe KN95 represents N95 masks manufactured in China. Unclear why they get a separate code. However, earlier this year many of these masks, when tested, were well below spec. These include the masks famously flown in by the Patriots. I have not since read any updates that attest to improved reliability of KN95s. So I would not consider them a reliable substitute for certified N95s in critical indoor exposure situations.

  • Corinne Reppucci says:

    Wonderful article,especially clear about the wearing of masks, associating with other people, i.e., service people in the home. Thank you

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