Last week we asked a Professor of Epidemiology at the Columbia Mailman School of Public Health, Stephen Morse, a few questions about living in New York City as COVID-19 continues to spread and we all try to safely navigate life here. The questions focused on our new normal, like, can I go to the grocery store, and what happens if I touch that cardboard box? As promised, we're back with another installment. Below, Morse answers our questions about going outside, wearing masks, getting into an elevator, and more.
We'll all have more questions as time goes on, and we'll keep asking them, so email us at [email protected] if you have anything you'd like answered.
What do you think about this comment claiming that being outside at all is not safe because of "the viral load" in New York right now? Is it safe to be outside?
The viral load story is quite amazing. I assume the “viral load” is based on the notion that there are a lot of infected people out there (as I’m sure there are, almost everywhere), and that they’re exhaling or expelling (ah-choo!) virus into the air, so the air must be laden with virus. I tend to think that’s not a very realistic risk, but we really don’t know.
If (as is generally believed) most of the transmission is by droplets, those settle pretty quickly and only go a few feet (hence the 6 ft. rule). Finer particles (aerosols) can go much further, and recent work reported that the coronavirus is stable for at least several hours in an aerosol, so the real question is how important is this in transmission of this virus. Unfortunately, we don’t know for certain. In fact, this is still unsettled even for flu (a totally unrelated virus but with an apparently similar route of transmission). However, the evidence suggests that this accounts for a relatively small proportion of the transmission, compared with droplets. The aerosols would also dissipate more rapidly with the wind outdoors (at the potential cost of carrying any virus even further).
Overall, with the present evidence, I’d conclude possible but not very probable.
Should everyone wear a mask outside?
I’ve always had mixed feelings about them. Chinese public health and medical officials strongly advocate them, and my colleague Ian Lipkin [the "master virus hunter" who advised on Contagion] was once skeptical but is now a true believer.
Our two main concerns are the current shortage of personal protective equipment for those who are at high risk of exposure (healthcare workers, caregivers for high risk or infected people), and developing a false sense of security and relaxing precautions as a result. I’d now probably be more in favor than before, if it’s not depriving those who need them most, and if people are attentive to their correct use, simply because it’s not always possible to practice strict “social distancing” in a city like New York.
But the best thing is to stay home as much as possible, and strictly observe those precautions we can probably all recite in our sleep now. “Hand hygiene” and “respiratory etiquette” (as it’s come to be called) are good lifelong habits and will prevent spread of many diseases, so if you haven’t done it before, this is a good time to start.
For more on this, Morse says, "We did a whole disquisition on this on the School’s website."
Many people have emailed to ask us if their building elevator is safe... If someone infected were in the elevator, say, 10 minutes before them, can they get it that way?
Elevators are a bit of a dilemma. The amount of ventilation and air exchange varies with different elevators, and of course that’s one place where we as individuals can’t control the risk, so it makes us anxious. It becomes of special concern if known COVID-19 positive patients are in the building, especially on the same elevator.
The question is probably moot for those wearing masks. For the rest, holding your breath until the ride is over (and not touching anything) is not generally an option. Although the risk is probably relatively low, we just don’t have good data on this. Most elevators don’t have air filtration systems, or UV-C (UV lamps in certain wavelengths that would inactivate virus but not harm skin or eyes). So we’re left with the low tech route.
One possibility: When building staff clean the elevators, they could also use a disinfectant spray (such as Lysol) several times a day. Of course, it’s all for naught if an infected person is coughing right next to you (or just before you got on), but it might reduce the risk. For most of us, it’s another example of how we can reduce the risk tremendously through prudent measures, but can’t completely eliminate it, just as in everyday life.
We know that if everyone in the country just stayed in their homes for two weeks, the virus would mostly grind to halt, but in the way we are doing this in NYC (where non-essential workers just stay home, in theory) how long would you estimate it will take to move the curve a little in our favor?
On staying home, I think we could have made the two week home sheltering much more effective if it had been started sooner and been better coordinated nationally. More surveillance (identifying virus circulating in the population, which is the same as “cases," who are sick and are a relatively small portion of those infected) would have helped.
The virus spreads primarily person to person, and needs a certain population threshold to keep going, so keeping most of us home could have a big effect. Of course, once we go out again, if the virus was still circulating or reintroduced from somewhere, it could be explosive since we weren’t exposed to the virus and would be susceptible. That’s why timing is so important.
Do you have a best estimate of when the peak will be and when this will be over, given the recent lockdown?
Nobody really knows when the peak will be, or when it will all be over. That depends partly on how effective these measures are in interrupting spread. One mathematical model suggests perhaps peak around the 2nd or 3rd week in April in most states (varies by states), tailing off in June. This is from the IHME (Institute of Health Metrics and Evaluation in Seattle); it was mentioned in Sunday’s White House briefing. However, this is [just] one model (although they’re good modelers)... All models vary greatly depending on their assumptions. And we can’t rule out reintroduction and subsequent waves later.
Would quarantining New York help at all, if there weren't a nationwide lockdown?
No. The virus is simply too widespread nationally.
