Four days of work, followed by 10 days of lockdown could help prevent another wave of infections. Here's how the idea compares to other reopening strategies.

• Researchers have devised a plan to reopen economies while preventing another massive surge coronavirus infections.
• Some have advocated for four days of work, followed by 10 days of lockdown. Others have proposed a cycle of 50 days of lockdown, followed by 30 days of reopening.
• Harvard researchers suggested isolating half of people ages 30 to 49, while telling the rest of the population to social distance.

Researchers have a plan to mitigate the risk of a second wave of coronavirus infections — a scenario many experts think is likely. For some, it's an alternating cycle of four days at the office, then 10 days under lockdown. For others, it's a switch-off between 50 days under stay-at-home orders and 30 days of relative freedom.

In all likelihood, these tactics won't prevent cases from rising again.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has said he believes a second wave is inevitable. An April report from the Center for Infectious Disease Research and Policy told states to prepare for an even larger wave of infections this fall and winter than we've seen thus far.

But it's possible that the US could see a "slow burn" of infections. Under this scenario, hospitals wouldn't become overcrowded and a second wave of cases would be smaller than the first.

"The infection would sort of limp along in the population," Dr. Elizabeth Halloran, a biostatistician at Fred Hutchinson Cancer Research Center and the University of Washington, previously told Business Insider. "We wouldn't necessarily stamp it out, but it wouldn't travel very fast."

Many researchers have suggested a way to achieve this outcome while limiting economic devastation and allowing people to resume normal activities.

Reopening looks different in each state

The pandemic has forced public officials to weigh the economic and psychological costs of lockdowns against the potential cost of human lives.

"Reopening is both an economic question and a public-health question," Gov. Andrew Cuomo said at a press briefing on April 11. "I'm unwilling to divorce the two. You can't ask the people of this state or this country to choose between lives lost and dollars gained."

The definition of reopening is different for each state.

Eleven states have yet to fully lift their stay-at-home orders, though nearly all have allowed retail stores to reopen. (A handful, like Illinois, New York, and Washington, allow curbside pickup only.) More than half of states have permitted dine-in service at restaurants, though most restaurants can only operate at 25% or 50% capacity. And at least 14 states are requiring all residents to wear face masks in public.

But given that a vaccine or treatment is still many months away at best, subsequent surges in cases are highly likely. Three different research groups have proposed solutions for mitigating that risk.

Strategy 1: 4 days of work, 10 days of lockdown

Uri Alon, a systems biologist at the Weizmann Institute of Science in Israel, recently advocated for a part-time economy in which employees switch off between going to the office and resuming lockdown. Alon presented his team's idea at the TED 2020 conference on May 20.

The model is based on data that shows coronavirus patients often don't show symptoms until at least three days after they're infected. The average incubation period is about five days, during which time a person can transmit the virus without knowing they're sick yet. Then once a person's symptoms start, research suggests the majority of COVID-19 patients are contagious for around 10 days.

"We're proposing a strategy which is four days of work and 10 days of lockdown," Alon said at the conference. "That way, if a person gets infected during work, they reach their peak infectiousness during lockdown."

Alon added that employees could work longer hours during those four days. He also suggested dividing the population into two groups and staggering work schedules: When Group A reaches its fourth day of lockdown, Group B could return to work. The model would help conserve coronavirus tests, he said, since people would only need to be tested once every two weeks, at the end of their lockdown period.

"It's equitable in the sense that everybody gets to go to work," Alon said. "You can keep production lines working almost continuously."

Alon said that the strategy could work for a single company, county, region, or country. Many European nations are already staggering students' return to school.

Strategy 2: Half of people ages 30 to 49 stay under lockdown

Harvard researchers recently determined that age-specific lockdown measures, combined with social distancing, could be just as effective as telling an entire country to stay home.

The researchers simulated what would happen if everyone in a certain age group in Lombardy, Italy, were told to shelter in place, while the rest of the population practiced social distancing. Their models suggested that the death count wouldn't drop much more than it would if only 50% of that age group were told to stay home.

The researchers also found that telling people in their 30s and 40s to shelter had a larger impact than asking people 70 and older to do so.

"If you think about it, people in the 30-to-49-year-old-demographic have some of the largest social circles, and those circles tend to be intergenerational," Bryan Wilder, a graduate student who led the research, said in a statement. "They have kids, go to work, take care of their parents, go out with friends and colleagues."

The most effective policy, the researchers found, was placing half of people ages 30 to 49 under lockdown, while telling everyone else to social distance in public. The researchers also suggested staggering work schedules, enforcing social distancing in restaurants, and prescribing times for people to go to the gym or grocery store.

Strategy 3: 50 days of lockdown, 30 days of reopening

A new study in the European Journal of Epidemiology modeled the effects of different lockdown strategies on ICU admissions and deaths across 16 countries. The researchers found that successful lockdowns have to be longer than the following periods of relaxed restrictions.

They proposed a strategy of 50 days of strict lockdowns, followed by 30 days of reopening in order to prevent overcrowding in ICU wards. The reopening period would still include measures like testing, contact tracing, and the isolation of infected patients and vulnerable groups.

The strategy would ultimately result in around 130,000 deaths in those 16 counties over the course of 18 months, the researchers found. That was compared to 7.8 million deaths if no interventions were in place during that same time period.

The researchers also considered a less stringent approach: 50 days of "mitigation measures" — social distancing, school closures, restricting large public events, and isolating infected patients and vulnerable groups — followed by 30 days of relaxed measures. But that strategy resulted in 3.5 million deaths, and overcrowding in ICUs, over the course of 18 months.

"Our study provides a strategic option that countries can use to help control COVID-19 and delay the peak rate of infections," Oscar Franco, a researcher from the University of Bern in Switzerland, said in a statement. "There's no simple answer to the question of which strategy to choose."