What does it mean to "make an impact" when we're dealing with an unstoppable COVID-19 Pandemic?
At Wehealth, we see ourselves as just one layer of pandemic defense among many more impactful ones, including vaccines, masks, quarantine and regular testing requirements.
Within this response toolkit, our goal is to empower individuals with the exposure information they need to seek rapid treatment and keep their close contacts safe. When enough of the population does this, it helps society and the economy stay open and healthy.
Between September 1st and October 15th 2021 approximately 2600 Bermudians tested positive for COVID-19 (
Bernews).
During that same period of time 264 Bermudians, 10% of everyone in Bermuda who tested positive, chose to anonymously notify others who they might have exposed to the virus.
Each contact notified an average of three other people for a total of 879 notifications sent.*
Based on this data and Bermuda's day to day case count, WeHealth estimates that Bermudians using the app may have helped avert up to 20% of the total case load during the Delta wave. Based on our projections this 20% reduction helped preserve roughly a week of normal economic activity.
Measuring how well any particular intervention does at achieving benefits for a society or individual is extremely difficult and very context dependent.
This article from Nature does a wonderful job explaining how we can try to quantify the impact of various government interventions. It also reveals just how hard it is to tease apart the impact of any single intervention from unique circumstances, accompanying interventions and simultaneous cultural responses to on-going out breaks.
Nevertheless, it's important that we do our best to understand how well the app is performing.
One way to think about how the benefit of a potential reduction in total case volume is in terms of thresholds and feedback. The longer case rates can remain under certain thresholds; the less restrictive our policies must be, the shorter duration we'll be put on any national travel advisories and the less likely our tourism will dip due to COVID
These thresholds and feedbacks are necessarily complex and change frequently so they're hard to model with certainty. One useful threshold we've observed is the 7 day rolling average of cases, wherein at about 75 cases per day, we start to close schools, implement curfews and stay home.
By keeping cases 10-20% lower than they might have otherwise been, we can all make big reductions in the economic and societal costs of COVID-19 to all Bermudians.
*This number is an estimation based on the data from of users who have chosen to share limited app-use data with us.