Shall we…track?

In a propagated epidemic with person to person transmission multiple waves of rising new cases are likely to occur till the susceptible population becomes a minority.

It’s simple mathematics: while we move in the same circles, after a number of days we can see a decrease in new cases. When our circle expands and starts mixing with other circles, more and more people get connected and expose themselves to the infection, hence the second wave.

This will continue till the virus runs out of susceptible hosts by either imposing total quarantine (unrealistic in this global world), herd immunity or by vaccination. With none of these in close sight, we should prepare for the next waves. Can we diminish them? Yes: distancing, tracking and testing, they all help.

McMahon, Glenda; Chatterton, Ken (2019): The epidemic incidence curve of a propagated-source outbreak. Loughborough University. Figure.

Good epidemiology practice requires tracing all contacts of a case, in order to warn and isolate them and to prevent further propagation of the infection. This activity requires a lot of resources (human and logistics) that can be easily overwhelmed, making tracing slow and inefficient, delaying isolation of the contacts and, as a result, letting infection spread further.

But what if we would all help? We can, each of us, for the next months, keep a daily journal, a log to write down all the persons we saw and talked with for more than 15 minutes during the day and the public places where we spent more than 45 min. Most of us can not rely on our memory to retrace all the persons we met and all the places we went for 2 weeks.  Writing it down in a notebook at the end of the day, it’s easy.

If we can ensure 80% tracing of each new case, rapid isolation measures can stop or control the outbreak.[1]

We do not need, nor want a state / public tracing technology. We can surely keep track ourselves, just in case we get infected, we will know who to warn. Those worried about their own records can shred the notes every third week. Let’s prepare, shall we? It’s not that hard.

Raluca Buzdugan / 22.05.2020

[1] DOI:  “Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts” by Joel Hellewell, Sam Abbott*, Amy Gimma*, Nikos I Bosse, Christopher I Jarvis, Timothy W Russell, James D Munday, Adam J Kucharski, W John Edmunds, Centre for the Mathematical Modelling of Infectious Diseases COVID-19 Working Group, Sebastian Funk†, Rosalind M Eggo†

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