Many news reports mention “contact tracing” as one of the required tools to open up economic activity, along with highly available testing. Given the much-lauded Apple-Google collaboration for a common technical solution for “exposure notification” and that many governments are releasing their own mobile apps, some privacy advocates are up in arms about the idea of having mobile devices track who individuals come in contact with and report this data to the government or “big tech.” Much of the coverage has focused on the technology or the privacy aspects, but very little has discussed contact tracing’s usefulness from a public health perspective.
What is “contact tracing” in the first place? It’s a function carried out by public health authorities at the local/state/provincial level whereby trained contact tracers work from a call center to communicate with individuals who may have been exposed to an infected individual so that they may be tested and quarantined. Tracers maintain a database of suspected and confirmed cases in their jurisdiction, along with confirmed test results for each case. Cases are typically reported by healthcare providers or labs or are self reported. Epidemiologists use the data collected by the tracers to determine outbreak hot spots, track the overall progression of the disease in the community and devise the appropriate public health measures to manage it.
Contact tracing has been the main method for managing SARS, MERS, H1N1, Ebola and other communicable disease in the past few decades and is demonstrated to be effective. COVID-19 is different in its scale from previous outbreaks, which is why it is estimated that 300,000 tracers may be needed in the U.S. alone to effectively manage the outbreak.
So what to make of the exposure notification apps and the Google-Apple solution? Most of the public health experts I’ve been talking to aren’t sure how to interpret and best use the data outputs and how to use them. My Gevity colleague Marty Pearce, an epidemiologist and expert in such things, has rightfully pointed out several times that there is no proven method for contact tracers to leverage this proximity-monitoring data, nor has any study established the public health effectiveness of harnessing this data. His opinions are shared by many public health researchers. Best practices have yet to be determined: What location and identifying data points should the apps collect? What level of privacy intrusion will North American citizens tolerate? What minimal proportion of the population must use an app for it to be effective? etc.
Germany, Australia, South Korea, Singapore and China have already released exposure-notification apps. The debate has seemed to focus on the various technical solutions — for example, centralized vs. decentralized databases — and the privacy and security implications thereof. Singapore has seen a surge of cases in May despite being the first jurisdiction to widely implement exposure notification. In North America, there is a patchwork of efforts across states and provinces. Several apps combine exposure notification with symptom checking, but none has solved the issue of traveling across local/provincial/state lines or country borders. While folks are debating the technical advantages of the myriad of apps developed, few are addressing the underlying issue — that each state and province are using disparate contact tracing databases.
This cheerleading of tech solutions is putting the carriage before the horse, in my opinion. Of much greater urgency should be enhancing the information systems that contact tracers are using as many are leveraging outdated software, or even paper (!) and spreadsheets in some cases, with data of highly variable quality. These systems should include efficient workflows specifically designed for contact tracing and outbreak investigation, allow for mass communication by tracers to contacts via email/ phone/ text, integrate lab test reports and healthcare provider electronic case reporting data, and eventually enable data sharing across local/ state/ provincial jurisdictions. This wish list might seem trivial to the layperson, but enabling it would be a monumental undertaking for public health authorities across the U.S. and Canada.
I suspect exposure-notification apps can eventually be researched and developed into useful add-ons to established contact tracing methods. But with North America already opening back up for business this month, why not invest heavily to strengthen the contact tracing support systems instead of chasing shiny new exposure notification toys that authorities don’t truly know how to use yet?