Risk Mitigation During the Winter Surge, and When to Quarantine

Risk Mitigation During the Winter Surge, and When to Quarantine

Pretty much wherever you live in the United States, your risk of being exposed to the SARS-CoV-2 coronavirus has never been higher (November 23, 2020). When the virus emerged earlier this year, experts anticipated the possiblity that winter would exacerbate the pandemic. That prediction is turning out to be true. My home county of Sacramento has not been spared, although we are starting from a lower base (fewer cases) than in some other places. I just saw data from a local hospital system where they COVID test everyone coming in for any kind of health care, and the positivity rate was almost 9%–up from 2-3% a month ago. That means it’s possible that almost one in every ten people you meet on the streets of Sacramento is carrying the virus and probably doesn’t know it.

Many states, counties, and cities have responded to the surge with new restrictions intended to break the wildfire-like community transmission that’s happening. But what can you, as an individual, do to protect yourself from infection?

The SacBee offers an excellent set of suggestions specifically related to the Thanksgiving holiday here.

Our scientific understanding of coronavirus transmission has changed since March (and continues to change). In general, here are the most important things you should know about how the virus spreads:

1. In most cases, people catch the coronavirus from other people. It’s uncommon (maybe even rare) to be infected by a contaminated object.
2. People who feel totally healthy can spread the virus, and in fact account for a large percentage of new case transmission. In other words, you might not know if you are contagious to others, and they might not know that they are putting you at risk.
3. People are most contagious in the two days immediately before they start to have any symptoms, and/or in the five days after they get infected.
4. The main mode of transmission is through the air, from infected people breathing, talking, singing or coughing.
5. Infectious dose probably matters. People who get more virus in their initial exposure are more likely to get sick, and are more likely to get sicker.

How can you apply this information?

Washing your hands and disinfecting surfaces is good. Managing the air you breathe is better. Imagine that somebody is smoking a cigarette. Now imagine all the ways you could minimize the amount of secondhand smoke you inhale. That’s a good analogy for avoiding tiny virus-carrying droplets in the air.

In Japan, public health messaging for months has wisely emphasized the 3 C’s:

closed spaces, crowded places, and close-contact settings

In other words, seek fresh air and keep your distance. If you must be around people from outside your household for any reason, do it outdoors whenever possible. If indoors, ventilate the space. Choose the largest room. Open all windows and doors. Turn on ceiling fans, bring out the floor fans, and run the HVAC (even though it wastes energy). Avoid crowds, and avoid small groups that are close together. Spread out as far as possible.

The SARS-CoV-2 coronavirus is more stable in cold temperatures than warm. (Remember the early outbreaks in meatpacking plants? Yep. Cold.) Sunlight and heat, which were plentiful a few months ago, are now scarce. So if you’re in an indoor situation, turn up the thermostat.

OF COURSE, wear a face covering and wash your hands. Don’t touch your face. Don’t touch other people.

Riding in the car together can be a particularly dangerous exposure. If you must do it, open the windows. Run the fan with maximum outside air.

In anticipation of the holidays, I especially recommend that you discuss IN ADVANCE any risk mitigation with your loved ones. If you wait until you are in the same room together, caution will fly with the wind. It’s socially awkward to not embrace, and to mask up–so you should have these ground rules established ahead of time.

A final important way to mitigate your risk: time. The longer you are breathing the same air as other people, the more virus particles uninfected people will inhale from any infected people in the group. Shorten the amount of time you spend around others, or in the same room or car. Brief encounters are safer than lengthy ones. (That’s why passing a stranger on a trail or sidewalk is very low risk.)

What if you have been exposed?

 Everyone has an obligation to the community to quarantine after close contact with a coronavirus-infected person. So what does that mean?

First, what is the definition of close contact? According to the CDC:

Someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period starting from 2 days before illness onset (or, for asymptomatic patients, 2 days prior to test specimen collection) until the time the patient is isolated. (Source)

In plain English, if somebody gets sick or has a positive COVID test taken within two days of the time you were in their presence for fifteen minutes, regardless of when the test result actually comes back, you should quarantine.

Notice that the definition of a close contact does not consider whether either or both people wore masks. Masks can help but they don’t absolve you from quarantine. Also, in my personal opinion, if the contact was outdoors, I think 15 minutes is a bit conservative.

What is quarantine?

Fourteen (14) days at home from the time you were exposed.

Most people who are destined to get sick from COVID do so within 5 to 10 days of exposure. A small percentage will still develop their first symptoms over the final four days. So 14 days covers it. Because that’s a long time, some countries are modifying their recommendations to ten days plus a negative test. But the official US policy, and the best way to protect others, is to stay away from other people for the full two weeks. 

Here are the CDC COVID FAQ’s.

Questions? Contact me.

Amy Rogers, MD, PhD, is a Harvard-educated scientist, novelist, journalist, and educator. Learn more about Amy’s science thriller novels, or download a free ebook on the scientific backstory of SARS-CoV-2 and emerging infections, at AmyRogers.com.