Testing, Contact Tracing, Isolation

Lessons from South Korea. And Germany. And Singapore. And Norway. And France.

Source: Worldometer, Our World in Data US data as of 3/25, Other countries based on number of tests as of 3/20/20.

South Korea was slammed hard with MERS (Middle Eastern Respiratory Syndrome) in 2015 when a traveler who had returned from three Middle Eastern countries led to 186 cases and 35 deaths. In the end, the outbreak had 17,000 cases of MERS in South Korea, but was stopped in two months. There are many factors that led to the end of that outbreak, but chief among them was South Korea’s rapid response with testing, tracing, and isolation. That experience, coming little more than a decade after the SARS outbreak devasted the region, prompted the South Korean government to prepare for the next one.

In the US, funds were invested in pandemic planning in the wake of 9/11 and fear of Avian flu, but over the years, and despite the 2009 H1N1 pandemic, that preparation withered away.

Meanwhile, back in South Korea…

Their COVID-19 experience differs substantially from that of Italy, so we can’t compare. Because an early case was linked to a megachurch, they were able to focus on testing and isolating 5000 cases before the disease spread to the community at large. Potential contacts were isolated until test results were confirmed. Many of the exposed were in a younger age group, less likely to have severe disease. This bought South Korea some time.

South Korea’s health officials utilized that time to ramp up testing, contact tracing, isolation and surveillance. Lessons learned from SARS and MERS. These efforts were crucial to flatten the curve in the short term.

As of March 24, 348,582 people have been tested. Of these, 9037 have been confirmed positive, for a population infection rate of 2.6%. It’s important to note that in most US cities, tests have been prioritized for likely positives, so we have a much higher positive rate. In South Korea, there has been some prioritization of tests, but the testing has included a much broader sample of the population. This has allowed epidemiologists to better understand the extent of the disease in the community and target the response efforts.

A recent article in the New York Times outlined the lessons from South Korea:

1. Intervene Fast, Before it’s a crisis

We are a little too late for this, but it doesn’t mean we can’t start now. Our current social distancing efforts will hopefully slow down the spread, but will not eliminate the virus. These efforts will simply shift the peak. South Korea is in danger of seeing another wave of illness, but widespread identification of cases through testing will minimize that second peak.

2. Test Early, Often, and Safely

This requires US cities to purchase tests and have the capacity to analyze them. We are still early in this outbreak locally. Testing sites must be established that minimize contact. South Korea has many good examples. These include drive through testing and “phone booth” testing for walk-ins. These keep potentially infectious people away from others.

3. Contract Tracing, Isolation, and Surveillance

South Korea used cell phone data to track contacts, which has been a substantial factor in identifying potential cases. They also shared information on the general location of cases, to alert people to the possibility of contact. While these methods were effective, cultural elements had a huge impact. South Koreans are more accustomed to this level of government involvement and were willing to trade privacy for prevention. It’s unlikely Americans would support utilizing cell phone tracking data, nor is it likely the federal government will approve such a measure. Furthermore, a large part of public health is preventing panic. Releasing location information is likely to cause panic and is a potential HIPAA violation.

More time consuming but doable is for public health investigators to notify potential contacts directly and to do increased testing in an area around a potential exposure. This isn’t a perfect solution, but maintains confidentiality and avoids a panic.

Florida has already enlisted public health and other health professions students to do contact tracing. San Antonio and the Texas Department of State Health Services did it during the H1N1 pandemic and it proved very effective.

Contacts would be required to isolate themselves, which includes household members. They would not go to work until their tests have been confirmed negative. It’s important that tests be performed at least four days after known exposure. Less than that may yield a false negative.

To conduct surveillance, cities can set up testing centers. While it may be necessary to continue to prioritize tests due to limited availability, expanding testing to include mildly symptomatic individuals will help us understand the level of infection in the community. This information allows us to target our isolation efforts more effectively.

4. Enlist the Public’s Help

We are already doing this to some extent. Public health crisis communication is essential. Messages that inform and calm the public are needed. Continued information on physical distancing and hand washing is valuable. Accurate information on symptoms should be shared.

South Korea also prioritized hospitalizations. Those at high risk for developing severe disease due to co-morbidities were the highest priority to be hospitalized. Those with lesser symptoms but still requiring medical care were cared for in temporary hospitals. In South Korea, this meant re-purposing public institutions and corporate facilities. This also meant those infected were isolated from household contacts, further limiting the spread. Many cities, including San Antonio, have the capability to do this if necessary, but we may be able to rely on household quarantine to limit spread.

It is tempting to say the US is too far behind to stop the epidemic. While we are behind in our response, we can slow it down. We have already severely limited physical contact in many cities. This alone will not stop the spread, as the virus will not simply die out. We know from previous outbreaks, including SARS and H1N1, as well as the 1918, 1957, and 1968 influenza pandemics that we can expect to see multiple waves. Our aim now is to stop the second peak. Dr. Ashish Jha, director of the Harvard Global Health Institute, explains that without testing, we are blindfolded. If we test, we can identify communities with higher disease burden so we can better target our resources.

Update: Germany followed a similar path to S. Korea, as did Norway. France didn’t. They started with a lockdown. France is now gearing up to do widespread testing.

Countries with enhanced testing — and isolation — have mostly slowed the spread of COVID-19.

Source: Worldometer, Our World in Data Johns Hopkins U

With our current measures in place, we may be where South Korea was in February. If we don’t increase testing, contact tracing and surveillance during this shut down, we will be where Italy is now.




Dr. Rohr-Allegrini is an epidemiologist and tropical disease scientist currently working to prevent diseases through immunizations.

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Cherise Rohr-Allegrini, PhD, MPH

Cherise Rohr-Allegrini, PhD, MPH

Dr. Rohr-Allegrini is an epidemiologist and tropical disease scientist currently working to prevent diseases through immunizations.

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