As we continue to navigate our new normal in this more careful world, we're questioning every move we make, washing our hands like Lady Macbeth ("will these hands ne'er be clean!") and figuring out the rest along the way. Luckily, Stephen Morse, Professor of Epidemiology at the Columbia Mailman School of Public Health, has been answering our questions for the past few weeks. Below, you'll find our latest batch, which includes everything from cleaning your face coverings to giving much-needed clarity to some of the latest headlines making the rounds.

We'll have more questions, you'll have more questions, and we'll keep asking them, so email us at if you have any you'd like answered. (You can find our previous Q&As with Morse here.)

If the average New Yorker is wearing a face covering outside, should they be cleaning this every time they come back inside? What's the best practice if so?

Cloth face masks can be washed, but probably don’t need it each time.

For N95s, washing and spraying with disinfectant damages them, and isn’t recommended (there are ways to decontaminate them for reuse, but they’re not for home use).  When there aren’t other options, some hospitals have been recommending healthcare workers to put their N95s in a paper bag until the next use.

As always, be very careful when taking your face covering off.  Don’t touch the front; if possible, use the earloops to remove the mask.  Always wash hands afterwards.

What do we know about how long the virus may last on clothes? Relatedly, is it safe to do drop-off laundry service, or is best practice to hand-wash clothing? 

There is limited data on how long the virus can last on cloth, also varies with temperature and humidity.  Bedsheets from patients’ rooms can remain infectious for hours or perhaps even a day.  If you’re talking about uninfected people just wearing street clothes, that’s a different matter.  Unless you’re in a highly contaminated environment, the amount of virus on the clothing is likely to be minimal, and the risks are probably small.  Many people like to change clothes when they come back (again, wash your hands after taking off the old clothing), for reassurance and esthetics.  I’d recommend it. Can’t hurt.

It's fine to use laundry service. If you go out (try to keep that to a minimum), many laundromats now only let a few people in at a time to allow distancing.  If you have dry cleaning picked up and dropped off (usually a no contact transfer), the deliverer has most of the risk, being outside and handling laundry. We can appreciate what they’re doing.      

A sign in Prospect Park reminds people of the 6-foot rule

A sign in Prospect Park reminds people of the 6-foot rule.

A sign in Prospect Park reminds people of the 6-foot rule.
Jake Dobkin / Gothamist

The latest headline I keep seeing is that 6 feet is not enough, that people should be at least 20 feet away from others — thoughts on this?

Droplets (the larger particles which are thought to have the greatest concentration of virus) normally travel only a few feet, so 6 feet is a pretty safe distance for avoiding droplets.  Some of the virus can be in fine particles (usually called aerosols), which can travel much further.  We know this happens, but don’t really know how much virus spreads by droplets compared with the fine particle aerosols.  The lion’s share is thought to be in the droplets.

But when you talk about 20 feet distancing? In New York City?  Really?  Most of the recommended distances in these studies aren’t easily achieved in the real world, except in places so thinly populated or so remote that the chances of becoming infected that way are almost zero anyway. 

Realistically, as long as we’re breathing, we can’t live a risk free life, but we can manage and reduce the risks.  Just like crossing the street.  Except that now that there are fewer cars, the risks are different.

Do you have any new thoughts on running and jogging? This article and topic is tearing our team apart! Is it okay for people to partake in these activities still?

Runners and bicyclists usually breathe more than the leisurely walker, so they should take special care with social distancing.

There is a recent modeling (theoretical) study that suggests runners and bicyclists need to keep further apart, because their movement creates currents that can propel the virus in the “slipstream.”  The authors of this study suggested runners and bicyclists should go side by side or in diagonal formation, instead of one behind the other, to reduce this risk.  Risk decreases with distance (as well as amount of ventilation or air movement).  Seems a sensible suggestion if you can do it, just for the extra margin of safety, but it’s hard to say how much a difference it would really make.

Another question is how this will work with the new recommendations to wear face coverings... especially when exerting yourself, face coverings can make it harder to breathe.  When that happens, rest and catch your breath (hopefully while still practicing social distancing).

[Note: A recent NY Times article noted that some runners are wearing Buff headwear as a face covering.]

Liz Phair had an interesting thought: "What if viral load really matters? What if putting people close together in hospitals is just compounding and aggravating their condition?" This has come up elsewhere in recent weeks, too. Thoughts on this?

It’s an interesting thought.  We really can’t say.  We think the virus dose someone gets when they become infected does make a difference, but by the time they’re infected and start producing their own virus, there’s probably much more virus inside them then they’d get from another infected person.

How long would you recommend someone quarantine after feeling better? (I just read this article on reinfection, if you have any overall thoughts on it...)

The reports from South Korea and other places that suggest possible reinfection, or extended duration of shedding virus, are still being sorted out.  These cases still represent a relatively small proportion of the "recovered," and there’s some debate whether they were testing problems, or true reinfections, or something else.  In the meantime, for those who can get tested, the standard is still two negative tests at least 24 hours apart.

Because testing is so limited, the recommendation we’ve been using as a rule of thumb has been to continue self-isolating for 4 days after temperature is essentially back to normal and symptoms have resolved.  This isn’t strongly evidence based, it’s the flu recommendation with an added safety factor thrown in.  As we gain more experience, and better testing, we’ll hopefully be able to give more confident advice.

A recent report claimed that the researchers could get positive test results from some recovered individuals as long as 8 days after “recovery”, but other work suggests that the PCR test may give positive results even after someone is no longer producing infectious virus.  There are always outliers, but the 4 day rule seems reasonable for now.

If someone in your home has Covid-19, how should this be handled — should they remain in one room for the duration, if possible, separate from everyone else? What if this is not possible?

If possible, they should have their own room with a door, try to keep the door closed whenever possible.  This is one situation where everyone agrees that both the sick person and the caregiver should wear a surgical mask or similar face covering.  Otherwise, same precautions (such as hand hygiene) apply.  Good if they also have a separate toilet, and put down the seat cover when flushing the toilet (the virus has been found in feces).

Many people don’t have this much space in a New York apartment, but New Yorkers are masters of improvisation.  Adapt social distancing as best you can.  As with flu, treat the symptoms, stay hydrated, and seek medical attention (nowadays, often a telemedicine consult) if the illness starts to get really worse.  Someone may be sick for several days, seem almost recovered, and then it comes back again.  Depressing, but not unusual.  Hopefully, it will pass.  Just keep an eye out in case you suddenly get much sicker.

The CDC has some useful good webpages on household precautions:

In China, they found that family members of patients might not feel sick, but could be infected and pass the virus on to others when they went out to do errands for the family.  This accounted for a number of cases limited and made it harder to control spread.  So household members should wear face masks and observe the social distancing and hand hygiene precautions if they go out, as much to protect others just in case they’re infected.

John and Stephanie Stislow and daughters Mira and Nona pose for 'Words At The Window: Self Isolation And The Coronavirus', a portrait series shot around the Ditmas Park neighborhood of Brooklyn.

John and Stephanie Stislow and daughters Mira and Nona pose for 'Words At The Window: Self Isolation And The Coronavirus', a portrait series shot around the Ditmas Park neighborhood of Brooklyn.

John and Stephanie Stislow and daughters Mira and Nona pose for 'Words At The Window: Self Isolation And The Coronavirus', a portrait series shot around the Ditmas Park neighborhood of Brooklyn.
Stephen Lovekin / Shutterstock

Is there anything new that you've heard about in the past couple of weeks that we should know about, or that surprised you, pertaining to the virus?

From the virologic point of view, not really.  We know this virus is very transmissible person to person, much like the flu but probably somewhat better.  Face to face contact is probably the #1 route of transmission.  This coronavirus is also somewhat hardier (than flu) on inanimate objects and surfaces; that’s why the advice to wash hands, and never touch your face unless your hands are clean (how many times have you heard that?).  “Social distancing” does work.

Because this virus is being studied far more than many others in the past (including flu), we’ll hear about all sorts of studies (some of them really expertly done) that will seem like surprises because this is the first time we’ve studied a virus like this in such detail.  There will be unique things, but probably we would have found this in other viruses if we’d studied them as thoroughly.  Don’t let these throw you.  For example, there are a number of good modeling (theoretical) and laboratory studies, but unfortunately we often don’t have real world data yet to help estimate the actual risk, so you’ll hear about these results before we can assess their practical significance.