There's a demonstrated way to avoid lockdowns and still stop the coronavirus' spread. South Korea has been doing it for months.

• South Korea has been lauded for its success in controlling its original coronavirus outbreak.
• Like Sweden, the country never fully locked down. But South Korea's epidemic curve quickly dropped.
• South Korea has tested widely and leveraged smartphone apps to share information with the public about where people with confirmed COVID-19 cases went.
• It also leans heavily on contact tracing to contain new outbreaks: After infections were linked to nightclubs in Seoul, South Korea traced and tested 46,000 people in less than two weeks.

Lockdowns help contain coronavirus outbreaks and prevent additional deaths — overwhelming scientific evidence supports the practice.

But it comes at a cost. Since most US states issued stay-at-home orders in March, the country's curve has flattened, but 40 million Americans have lost their jobs. Sweden, by contrast, didn't lock down or close schools and restaurants. But experts have criticized that approach, pointing to Sweden's 12% death rate.

The choice between locking down and saving lives may be a false one, however — and South Korea's experience proves it.

South Korea never went into a full lockdown, but its death rate remains low: around 2%. In late-February, after cases started to shoot up, it was able to get daily case numbers on a downward trajectory in just 20 days.

The country has closed schools on and off again, and it recently shuttered parks, museums, and art galleries for two weeks after a spike in cases. But South Korea has yet to levy a widespread stay-at-home order or put firm restrictions residents' movements. Here's how the country pulled it off.

Testing, testing, testing

South Korea reported its first coronavirus case on January 20 — the same day as the US. At first, the number of infections remained low, but a super-spreader event at a Daegu church caused the country's case count to jump from 29 cases on February 15 to more than 2,900 two weeks later.

But the country quickly implemented widespread testing, which helped health officials find and notify potentially infected people, then send them into quarantine. For many weeks, South Korea had the highest testing-per-capita rate of any country in the world.

By March 17, more than 270,000 South Koreans had been tested, in large part at drive-thru and walk-through facilities. The number of new daily cases shrank day after day starting on March 1, and the nation's epidemic curve dropped.

But the tests weren't the only part of the strategy — South Korea's government also communicated the results of that testing to citizens in real time and enabled them to find out about their own potential exposure.

Using technology to boost contact tracing

According to a South Korean government report called "Flattening the curve on COVID-19: The Korean Experience," lockdowns haven't been needed because officials can easily alert people about whether they've come near someone who tested positive.

The government communicates how many people are infected in each geographic area and city in real-time, constantly updating national and local government websites that track case totals and the number of residents tested. It also offers smartphone apps that send people emergency text alerts about spikes in infections in their local area.

Additionally, South Korea implemented a comprehensive contact-tracing program in order to find the right people to test. After a positive case gets confirmed, officials then use GPS phone tracking, credit-card records, medical records, and video surveillance to trace an infected person's travel history.

The government publishes anonymized data about where each infected patient went — down to the minute — before they were diagnosed on a public website as well as two apps, so others can check to see if they crossed paths.

Once residents test positive or are suspected of coming into contact with a coronavirus patient, the government encourages them to voluntarily download self-quarantine apps to monitor their condition. The apps can connect people to a doctor if needed, and also also set off an alarm on a user's smartphone if they venture outside a designated quarantine area.

A recent outbreak underscored the effectiveness of this approach.

After several people who visited nightclubs in Seoul's Itaewon district tested positive for the virus in early May, dozens of new COVID-19 cases started to get reported each day. Given the thousands of Koreans who had been at clubs that weekend, South Korea was staring down an infection cluster that threatened to catalyze another nationwide outbreak.

But within two weeks, the government traced and tested 46,000 people (for free) and isolated those who had been exposed. The police worked with telecommunications companies to use cellphone data to confirm who was in Itaewon that weekend. Daily case numbers dropped back down to the single digits by mid-month.

It would be difficult for US to replicate South Korea's contact tracing

South Korea's level of contact tracing isn't possible in the US yet. Besides concerns around privacy and data tracking, the US's number of new cases per day hovers around 20,000. So an effective tracing program would need to be able to pin down the movements and contacts of each one of those people as the total continues to grow larger.

The US needs to and train at least 30 tracers for every 100,000 Americans, according to The National Association of County & City Health Officials. (That's about 100,000 tracers in total.) But only seven states are on track to reach that goal, NPR reported.

According to NPR, as of early May, 44 states had about 66,000 total contact tracers. Some public-health experts think the size of the US's contact tracing army needs to be three times that; one group called on Congress to build a 180,000-person workforce that would cost $12 billion.

Currently, public-health forces are spread thin. Just tracking down at least 91 people who a Missouri hairstylist exposed to the coronavirus was a challenge for the local health department.

"I'm gong to be honest with you: We can't have many more of these," Clay Goddard, director of the Springfield-Greene County Health Department, said at a news conference on May 23. "We can't make this a regular habit or our capabilities as a community will be strained."

States also aren't getting robust guidance from the federal government as to how to amass and train their contact tracers; attempts to fund such efforts have stalled in the Senate. Roughly 20 states told NPR they would use smartphone apps to assist with tracing, but said they weren't sure which app they would use and hoped the government would in part pay for licensing.

In the next few months, it's imperative that the US bolster its contact tracing, since experts predict the fall could bring a second wave of coronavirus infections.