Few countries around the world appear to have had as much success in tackling COVID-19 as South Korea, with many attributing this success to the success of their contact tracing and testing initiatives.  New research from the University of California San Diego suggests equally important is the level of disclosure health authorities make about those who do test positive for the virus.  The paper also suggests that these three measures are vastly more effective at reducing the death-toll than comprehensive stay-at-home orders.

The country, which has received significantly fewer deaths as a result of the virus than other nations, began sending text messages to citizens whenever someone was confirmed to have the virus in their neighborhood, as well as information about that persons’ travel.

The research combines foot-traffic data from Seoul with publicly disclosed information on the precise location of those people who had tested positive.  The analysis suggests that the public disclosure was highly effective in allowing people to target their social distancing, especially for vulnerable populations who can more effectively avoid areas with high infection rates.

“Our data shows that South Korea’s public disclosure information was effective in changing citizens’ behavior to drive down the rate of infection, without government-imposed lockdowns,” the researchers say. “This pattern is particularly pronounced during the weekends and among those over the age of 60.”

Containing the spread

The paper highlights how Seoul, with its 10 million or so inhabitants, managed to have less than a thousand confirmed cases and just three deaths, despite being one of the most densely populated cities in the world.

The city didn’t use social isolation restrictions, but instead provided inhabitants with real-time information on individuals that had tested positive, with a dedicated website and app providing real-time information.

The alert typically contains the age and gender of each confirmed case, along with a log of their movements.  The travel history is based upon contact tracing and data from both mobile phone and credit card records.

The researchers highlight that such an approach was possible in large part due to the laws in the country surrounding the public sharing of information on people with infectious diseases, with significant changes introduced after the MERS outbreak in 2015.  These changes allow the Korea Centers for Disease Control Prevention to tap into GPS data, credit card data and surveillance camera footage to recreate the movements of each infected person up to one day before their symptoms emerged.

The study reveals that this information prompted some significant changes in public behavior, with greater movement in areas with fewer confirmed cases, and less movement in areas with higher numbers.

The best strategy

The researchers tapped into resident movements and the number of confirmed cases via epidemiology models overlaid with economic geography data to predict the spread of the virus throughout the city.  They believe that the current strategy will result in approximately 925,000 cases of the next two years, with 17,000 deaths, and a loss of 1.2% of GDP.

These results were then compared to a second model where a partial lockdown was imposed, but with no public disclosure.  To try and ensure like for like comparisons were made, the researchers assumed that approximately 40% of the population would need to stay at home for up to 100 days to have the same number of cases achieved via the full disclosure approach.  The partial lockdown method, however, results in a 1.6% hit to GDP, with 4,000 more deaths.

“Our research shows that public disclosure mostly helps the elderly more effectively target social distancing which in turn saves more lives, at least 4,000, according to our projections,” the researchers say.

A balanced approach

The modeling suggests that lockdown strategies impose not only a higher health risk, especially for older people, but also economic consequences for the working age population that are roughly twice as high as that achieved using the South Korean approach.

“The flow of people across neighborhoods generates economic gains from the optimal match of people with the place of work and leisure,” the researchers explain. “In the current strategy, individuals with a high health risk commuting to a neighborhood with many detected cases can change their commuting pattern, while individuals with low health risk can make a different choice.”

Such an approach allows those who can work from home to do so, while others can continue commuting to work when safe to do so.  Full lockdown measures seldom provide that level of nuance, and are more of a blunt instrument.

The authors provide a direct comparison with China, who introduced a full lockdown, and saw a near 10% fall in GDP in the first quarter of 2020.  They believe that in the absence of a vaccine, a more targeted approach to social distancing is likely to be the best approach to halting the spread of the virus whilst minimizing the economic damage done.

“We view the public dissemination of information in Korea as one way to accomplish that,” the researchers conclude. “We are hopeful that perhaps there could be other more effective ways to target social distancing to get the maximum benefit for the least cost.”