As European countries settle into weeks of tough measures to limit the spread of COVID-19, governments are beginning to chart possible routes out of their lockdowns. Austria and Denmark have both announced an easing of restrictions, with the opening of small stores and elementary schools.

Researchers in the U.K. have presented the government with a different proposal, under which young people aged 20-30 would be the first to be allowed to leave their homes and get back to work—once the infection rate has been brought under control in the next few months —leaving their parents and bosses stuck at home.

A research paper by economists at the University of Warwick published this week argues that the 20-30 group would be at relatively low risk of suffering severe cases of COVID-19 if they began to rejoin the workforce and breathe some life back into the economy. It also suggests that 20-30 year olds may feel the economic impact of remaining in lockdown more severely than older adults. Under the proposal, only young private sector workers who don’t live with their parents or any older adults would be allowed to leave lockdown—a group that includes 4.2 million people in the U.K. (Much of the public sector, including government employees and healthcare workers, has continued to run as normal.) The proposal is being studied by British government officials, according to the Financial Times.

The idea is controversial. Epidemiologists agree that until a vaccine for the virus emerges— not expected for 12-18 months—any loosening of lockdown measures carries the risk of increasing the spread and the death toll of the virus. Scientists say more work is needed to model the impact of different ways of easing lockdowns.But as governments grapple with the painful economic fallout of their measures, the pressure is on to find options that enable some activity to restart in the coming months, or at least before the end of the year.

“There is no risk free way forward from our current situation,” says Andrew J Oswald, one of the Warwick paper’s authors. “So we’re looking for a solution that balances the economic objectives and the epidemiological objectives. Young people fit that bill rather naturally.”

Here’s what to know about the idea of relaxing measures for younger people – and the other possible ways out of lockdown.

What is the economic case for releasing young people earlier?

The U.K. has been under a nationwide lockdown—similar to the measures imposed in many countries in mainland Europe—since March 24. Only essential workers are allowed to leave their homes for work, and only the children of those workers are allowed to go to school. Most people are only allowed to leave their homes to go for brief periods of exercise or to buy food or medicine. Gatherings in public of more than two people are banned.

Oswald argues that, while the entire U.K. population faces “severe economic risk” from those measures, young people are likely to be particularly hard hit by a looming recession. “They’re the lowest-earning age group,” he says, and they’re unlikely to have the savings or protected income that older people and retirees could rely on without having to go out to work. “They’re also beginning their careers and this [period of lockdown] might have long term deleterious effects on their career trajectory.”

Allowing the 4.2 million 20-30 year olds—around a sixth of the U.K.’s workforce—to return to work would create a kind of “mini economy,” Oswald argues. Young workers could communicate with their bosses and older colleagues online, while helping to restart businesses’ activity. That would allow young people to earn a living, and prosperity to spread to other demographics.

How would releasing young people from lockdown affect the spread of the virus?

Though young people die at a lower rate from COVID-19 than older people, they are by no means immune to the virus. The Warwick paper argues that allowing 20-30 year olds to return to work while older people stay at home would add “a reasonably small, but unfortunately not negligible” extra health risk for the U.K. population. It suggests that the number of additional premature deaths caused by releasing the young people would be around 630. The number is based on the current average death rate from COVID-19 for this age bracket, of 0.03%, an estimated 50% infection rate, and the number of people in the bracket in the U.K., 4.2 million.

But the purpose of including people in the 20-30 age group in isolation measures in the first place is not to protect them, says Liam Smeeth, a professor of clinical epidemiology at the London School of Hygiene and Tropical Medicine. “The point is to lower transmission rates for the virus in society as a whole, and they would definitely be increased if young people leave isolation.”

Aris Katzourakis, a professor of genomics and evolution at the University of Oxford, says the 630 figure does not take into account the potential knock on effect for the infection rate. Though the proposal envisages only 20-30 year olds who do not live with their parents re-entering the workforce, Katzourakis says there’s “no way” to do it without increasing the exposure of older people to the virus. “If you’re leaving your home to go to your workplace every day and come back, you’re increasing your contact with other people, and those people you’re coming into contact with are increasing their contacts with other people too, and so on. It’s true that the impact might be low. But that hasn’t been explored yet.”

Though the young don’t tend to suffer as severely from COVID-19, Katzourakis says there’s some evidence that they could spread it more than older demographics do. Since young people are more likely to have fewer symptoms, they are less likely to be aware they are carrying the virus.

Still, Katzourakis says that young people may well be the first groups to be released from lockdown measures in the long run. “I imagine that’s probably what [the U.K. government] is going to do eventually. But we’d need very tight monitoring systems on track to make sure that we can see how it affects infection rates.” Testing for the virus would need to be carried out on a large scale, and systems to track people’s contacts would need to be in place, he says. “If it proved a miscalculation and got out of hand, we’d be back at square one.”

What other routes are there out of lockdowns?

There will be no sudden, wholesale end to the changes recently imposed on societies, says

Smeeth. “It’s going to have to be a gradual, phased process in some way.” There are a range of options for what such a process would look like.

Governments in several European countries, including the U.K., have floated the idea of “immunity passports,”, which would allow people who have already had COVID-19 and have antibodies to protect them from contracting it again, to abandon isolation. But scientists say there are major obstacles to such a system, including the lack of widely available tests for antibodies and the still unresolved question of how long—if at all—immunity to the virus lasts.

Other options for easing the lockdown being discussed include lifting measures in geographical regions where there have been fewer cases, or to use a stop-start process, in which some measures would be lifted and reinstated as the rate of new infections falls and rises, with the aim of keeping cases at a manageable level for the health system.

On April 6, Austria became the first European country to announce a relaxation of its quarantine after recording a downward trend in the growth rate for infections. The government will allow small stores to open first on April 14, and then larger stores and malls on May 1. Social distancing rules will remain in place, as will a requirement to wear masks in public places.

Denmark, meanwhile, has decided to start easing its lockdown by reopening kindergartens and elementary schools from April 15, as children are at a low risk of contracting serious cases of COVID-19. Both Austria and Denmark say that measures will only be relaxed further if cases remain stable. “This will probably be a bit like walking the tightrope,” said Danish Prime Minister Mette Frederiksen.

For Smeeth, reopening schools is a sensible option for easing lockdowns, because managing children is easier than managing 20-30 year olds. “With young adults, you can’t stop them moving around in random directions in random combinations of people with all different levels of contact. It’s very hard to predict.” For school kids, though, it would be feasible to create a situation in which parents drop them off at school and bring them home, meaning there’s only transmission at school and within children’s homes.

There are no good options, though, for exiting an unprecedented shutdown amid a global pandemic. “As scientists we can give the government all the information we have, but then they’ve basically got to guess how the public will respond to partial loosening of restrictions.” Smeeth says. “I don’t envy the politicians right now.”

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Write to Ciara Nugent at ciara.nugent@time.com.