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Share your #CoEpi status today to save a life from Coronavirus

Late Saturday evening, Leap Day Feb 29, 2020, we learned from the genetic sequence of their coronaviruses that someone north of Seattle who was just diagnosed the day before with COVID-19 had (with high probability) a virus directly descended from that of the first Washington case, sampled Jan 19. The same day, we learned that another person just south of Seattle died of COVID-19, and that dozens of others are likely infected there. Since then, public officials have been uncovering more and more previously hidden cases, and will be discovering far more in coming days.

This outbreak has been spreading exponentially undetected through our community for 6 weeks now, and epidemiological estimates put the total likely infections in the Seattle area somewhere in the range of hundreds to thousands.

This is an example of something that emerges from the unforgiving math of exponential growth of a deadly disease outbreak like this: every single case, if left undetected and unchecked, spreads to hundreds of people after a few generations, thousands after a couple more, and tens of thousands by about a dozen. And COVID-19 has an infection fatality rate somewhere around 0.5% for people with well-functioning non-overloaded health care systems, so someone is likely to die for every 200 people infected.

What now?

What that means for each of us is that there is no time to wait: we must stop as many of the chains of transmission of the COVID-19 coronavirus as possible today. Every chain of transmission we interrupt will save a life. If our communities don't take appropriate social distancing measures (shutting down schools, canceling nonessential meetings and travel, having everyone nonessential work remotely, etc.) until it's too late, every chain of transmission stopped today will save a life in about 1-2 months, and every infection allowed to occur will (on average) likely kill someone.

If our local public health officials take the threat seriously and immediately start canceling everything they can and testing and isolating all contacts of suspected cases, things won't get worse quite as fast. As shown by Singapore's rigorous contact tracing and social distancing measures, it's possible to bring down the number of people infected on average by each case, called R, from the virus's natural level (R0) of ~2.5 to something closer to 1.1. So far, only China has managed to bring R down below 1, by completely locking down entire cities and provinces.

Even just slowing the outbreak is tremendously valuable: if too many people get infected too fast, as occurred in Wuhan and is now occurring in Iran and possibly parts of Italy, health systems will be strained past their capacity and not everyone with moderate illness will be able to get the care they need, and some of those will progress to critical condition and die who wouldn't have otherwise. In such a situation, the case fatality rate can appear (and be) much higher: Wuhan measured a 2% death rate, and likely only missed about half the total infections, meaning that twice as many infected people likely died there as are currently dying in places like Korea and Singapore (closer to 0.5%).

It's likely that a vaccine and/or effective therapeutics will be developed and tested against COVID-19, but it's also likely that it'll take a year (or anywhere from 6 months to 2 years) for an effective prophylactic countermeasure to come into widespread use and further slow down transmission enough to force the outbreak to die down. During that time, our only defenses are non-pharmaceutical interventions (NPI): testing, isolation, quarantine, awareness, and social distancing to limit spread.

So, what can you do?

To start with, follow all the advice being given by local public health officials, and: wash and sanitize your hands frequently, don't touch your face in public, stay home and avoid close contact with family if you're sick, work from home and cancel all nonessential travel and meetings if you can, don't shake hands, avoid being within 6 feet of anyone coughing, avoid close face-to-face conversations entirely (sit/stand farther apart), and sanitize surfaces frequently.

But you can (and must) do more. In order to maintain such constant vigilance over the long term, and be able to relax it only when it's safe to do so, we all need to know how potentially infectious all of our contacts are, so we can practice extra care and avoid participating in one of those transmissions that will eventually kill someone vulnerable.


We (a rapidly growing diverse team, with experience building communities to create open-source digital health tools, rapidly building mobile apps using location and proximity technologies, rapidly scaling cloud services, and fighting infectious disease through the healthcare and public health systems) have started a project we call CoEpi, short for Community Epidemiology in Action. We're working on a mobile app that will make it easy for everyone to privately track who they've been in contact with, and anonymously share reports and update on their own symptoms and likely contagiousness, whether they have a cold, flu, COVID-19, or any other contagious disease. It's not ready yet, but we're trying to build it as fast as we can. (If you or anyone in your network might be able to help, we could use the assistance.)

But #WeCannotWait - you need to start now

But even if we get an app together in record time, it will be too late to save some of the lives we could be saving today. So we need your help to implement #CoEpi, manually and socially.

If you're currently experiencing cold or flu symptoms, we need you to tell everyone you've interacted with the details. They need to know when you first came down with symptoms, when you have a record of interacting with them face to face (look at your calendar, Google Maps timeline, ask your family, or whatever you need to do to figure it out), and what the progression of symptoms was. (Did you get a sore throat, congestion, or a cough first? Did you develop a fever? Anything else?) Use a spreadsheet (Google Sheets can be shared with your contacts), write everything down, or otherwise make sure you don't forget the important details. Keep your contacts posted as those details change, so they know what to expect.

If you're not experiencing symptoms, ask everyone you talk to what their #CoEpi status is. If any of your contacts were symptomatic while, or within a day or two after, you saw them face to face, be on the lookout for similar symptoms yourself a few days later, and start being extra careful about hygiene and personal space even before you feel anything. Because the virus that causes COVID-19 can be transmitted while people do not have symptoms, early notification of exposure can encourage people to self-quarantine when they may be contagious but before they are sick. This is critical for stopping wide-spread transmission.

Spread the word

And if you're willing to help spread the word, you can help protect yourself by announcing your #CoEpi status on social media and asking all your contacts to do the same. Every one of your friends and coworkers who practices good #CoEpi communication and transmission-prevention behaviors lowers the risk that you personally will catch COVID-19, and that you might pass it along in a long chain that eventually ends up killing someone in your community's parent, grandparent, or vulnerable relative.

We need the message and practices of #CoEpi, of community epidemiology and social-network hygiene, to spread virally, and faster than this COVID-19 coronavirus, so we can slow it down long enough to keep too many people from dying before a vaccine or prophylactic drugs get into mass production and distribution.