Digital Tracing Discarded as Authorities Manually Hunt Hantavirus Contacts
Experts warn that Bluetooth-based contact-tracing tools lack the precision required for small-scale, high-fatality outbreaks where every link in the chain must be accounted for.
Following three deaths on a cruise ship attributed to Hantavirus, Australian health authorities have abandoned reliance on digital contact-tracing applications in favour of a rigorous, manual investigation. Officials are currently conducting a person-by-person inquiry to confirm the movements of 29 individuals who disembarked from the vessel, aiming to identify exactly who they contacted and where they went.
This decision marks a significant shift from the broad-scale strategies employed during the global pandemic. While contact-tracing apps utilising Bluetooth technology were widely deployed starting in 2020 to detect proximity between infected individuals, experts argue they are unsuitable for this specific outbreak. Dr Emily Gurley, an epidemiologist at Johns Hopkins University, stated that the number of cases is small, making it critical to trace all contacts exactly to stop transmission.
The limitations of app-based data become apparent when dealing with a highly fatal disease like Hantavirus. Broad app data collected from a vast swath of devices would not be accurate enough to pinpoint where the virus might have hitchhiked to next. During the COVID-19 pandemic, such tools were designed to understand population-level risk and encourage self-quarantine rather than tracking individual infection chains. However, the high fatality rate and limited case numbers of this Hantavirus outbreak demand a level of precision that digital proxies cannot provide.
Consequently, officials have initiated a labour-intensive process that starts at the source, an infected individual, and moves outward to verify every interaction. This manual approach assumes full cooperation from the 29 identified individuals and their contacts, contrasting sharply with the passive nature of app notifications which often rely on users to respond. Gurley noted that during small but highly fatal outbreaks, more precision is required, a standard that current Bluetooth proximity technology struggles to meet.
The historical record of contact-tracing apps during the pandemic supports this caution. While the technology worked better in carefully managed European jurisdictions, it did not significantly slow the spread in the United States. Issues regarding privacy, the requirement for always-on access, and struggles with accuracy, including false positives and negatives, have further highlighted the limitations of these tools for specific, contained outbreaks.
As the investigation continues, the focus remains on the hard work of manual tracing rather than the efficiency of automated systems. For a disease where every person on the cruise ship can theoretically be directly tracked, authorities are choosing the difficult path of human verification to ensure no potential transmission chain is missed.
