The global experiment of exiting lockdown

The global coronavirus crisis is entering a trial-and-error phase as countries begin to tiptoe out of lockdown.

Why it matters: The decisions of what to open and when could determine whether economies stay afloat, and whether fresh lockdowns will be needed if cases spike again. U.S. states now considering their own exit strategies will be watching closely.

Driving the news: Europe led much of the world into lockdown, and is now attempting to find a path out.

• Denmark started by opening grade schools and day care centers. Some parents rejoiced, but others resisted (the Facebook group "My Child Will Not Be a Guinea Pig for COVID-19" has 40,000 members).
• Germany's small shops and car dealers reopened this week, but beauty salons will wait until May 4 and restaurants possibly much longer. Students will return to school in waves, beginning with those taking exams. Religious services and other large events won’t return until Aug. 31.
• Austria's approach is similar but somewhat expedited (bars and churches can open May 15). It will be implemented in two-week increments to allow time to track new cases.

In the hardest-hit countries, the opening will be slower.

• Spain is finally letting children outside after forcing them to remain home for five weeks. The strict lockdown remains in place, but factories and construction can resume.
• Italy has phased in some manufacturing, and Prime Minister Giuseppe Conte said Wednesday that the world's longest-running lockdown could begin to ease on May 4.
• France won’t lift its lockdown until May 11 to give the government time to build up testing capacity and medical supplies.
• The U.K. has resisted calls to release an exit strategy. Foreign Secretary Dominic Raab said the country had “sacrificed far too much to ease up now.”

Elsewhere in the world, strategies are emerging to re-open economies while limiting potential second waves — including some that use tracking policies that are likely too invasive to be useful as models for the U.S.

• Chile plans to issue "immunity passports" to allow those who've recovered from coronavirus to return to work. European countries may follow suit once large-scale antibody testing is available — though the passports could also provide a perverse incentive to become infected, and it's unclear how long immunity lasts.

• South Korea uses cell phone data to track down those exposed to the virus, and is now issuing electronic wristbands to ensure that those ordered to self-quarantine remain home.
• In China, people are required to show authorities a cell phone app to confirm they haven't been deemed a contagion risk. China, like several other countries, has also tightened border controls to avoid importing new cases.
• Singapore and Japan may show the dangers of easing up too soon. Both countries successfully contained initial outbreaks, but have since seen case counts climb.

The bottom line: Countries generally agree that social distancing must continue, and special precautions are needed for the elderly and at-risk. But the varying approaches, particularly on schools, underline how much we still don’t know about the virus and how it spreads, even as we loosen our protections against it.