Community Spread of COVID-19

by Michael Ainscough, MD, MPH

We’ve done well.  We’ve been lucky.  Sometimes to win a tough contest, you need to be both good and lucky.  The contest is not yet over. 

New York may be peaking, but more important for us are the numbers of COVID-19 cases in St. Louis and our neighboring counties which are still rising.  Each community’s epidemic curve often depends on when the first case arrives, when that case is quarantined (or not), and how contacts are traced by public health. The first cases are always travel related, either a resident goes on a trip and brings it back, or a contagious traveler comes into the community. 

The first case in Washington County was travel-related.  The second case was a healthcare worker.  Both have fully recovered and completed 2-week quarantine periods.  No additional cases related to those two initial cases have been reported.    

It is true that we have been somewhat sheltered from the storm out here in rural Washington County.  We are certainly doing the right things to ward off the coronavirus… sheltering in place, leaving home only for essential travel, social distancing, hand washing and most recently wearing masks.  Some stores have installed plastic screens at checkout counters.   

It’s coming down to crunch time.  Forecasts are for the epidemic to peak at different times in various cities in the next few weeks.  People, possibly contagious, from those hot zones are still on the move.  The CDC now says people can be contagious one to three days before they develop symptoms, even if they are only mildly symptomatic, and even from just talking.

When a community reaches a critical mass of cases, some cases will have mild or no symptoms and will go undetected.  Those unknown contagious cases will begin to spread the virus in the process known as community spread, meaning that new cases have no history of recent travel. 

A University of Texas report indicated that even counties that have only a few reported cases may already have sustained, undetected outbreaks.  It found that even in counties with just one reported case, there’s a greater than 50% chance that an outbreak is already taking place.  The lag time exists because people who are exposed to the virus today don’t get sick for one to two weeks.

The Illinois Department of Public Health has already advised that COVID-19 is community spread in Illinois.  That means that county health departments’ case contact tracing will vary.  Because of larger numbers of known and probable cases, all contacts might not be traced.  Community spread is definitely occurring in the Chicago area.  It is not as clear in rural areas.

As of Sunday, the St. Louis metro area has 1,422 confirmed positive cases.  St. Clair County has reported 82.  Randolph County has 24.  Clinton County has 14 cases.  With numbers like that, cities are seeing community spread of the virus. 

By venturing out into an area with community spread, you are at increased risk to get the virus and give it to others.  If we could all stay home, or at least within Washington County borders, for the next month, hopefully the threat would pass.  That is not realistic.  We can’t stay home that long, and even after the peak, it will not be completely safe to resume all activities for a while. 

If Washington County gets several cases, transmission of the virus will likely become community spread in our cities.  We don’t want to get to that point.  A couple months ago, we started living on a disease-free island, but people kept coming and going.  At some point our luck may run out. 

An epidemiologist at Yale, Jonathan Smith, shared this advice for areas with community spread:  “You should perceive your entire family to function as a single individual unit; if one person puts themselves at risk, everyone in the unit is at risk.  Seemingly small social chains get large and complex with alarming speed.  If your son visits his girlfriend, and you later sneak over for coffee with a neighbor, your neighbor is now connected to the infected office worker that your son’s girlfriend’s mother shook hands with.  This sounds silly, it’s not.  This is not a joke or a hypothetical.  We as epidemiologists see it borne out in the data time and time again and no one listens.  Conversely, any break in that chain breaks disease transmission along that chain.

“Social distancing measures are not about individuals, they are about societies working in unison.  People are already itching to cheat on the social distancing precautions “just a little” – a   playdate, a haircut, or picking up a needless item at the store, etc.  From a transmission dynamics standpoint, this very quickly recreates a highly connected social network that undermines all of the work the community has done so far.  Don’t cheat.”

The virus doesn’t discriminate.  No one is immune.  Do your part to protect yourself, your family and your neighbors.  Don’t put yourself in a position to transfer the virus.  Stay at home.  When you must go out in public for essential reasons, practice social distancing.  Wearing a mask is a personal decision, but it does not replace the need to maintain social distances.  Wash your hands after contacting high-touch surfaces (door handles, counter tops) in public places.  Leave non-perishable groceries and mail in a garage or separate room for 24 hours before bringing them into the main house.   

We are in this community together.  In any crisis we all have a small part to play.  We all should try our best to prevent the spread.  Be selfless for others.  Practice social distancing and stay healthy.

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