A rolling cycle of 50 days of strict lockdown measures followed by 30 days of easing of restrictions could be an "effective" approach for managing Covid-19 until there is a vaccine, research suggests.
This model would keep intensive care demand within capacity and "may allow populations and their national economies to 'breathe' at intervals", according to a study published in the European Journal of Epidemiology.
There are currently no effective treatments for coronavirus and a vaccine that is widely available is likely to be at least a year away.
A continuous, three-month strategy of suppression measures, such as strict physical distancing and lockdown, would reduce new coronavirus cases to near zero in most countries, the study indicated.
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Looser mitigation strategies such as hygiene rules and shielding of vulnerable groups would require approximately six-and-a-half months to reach the same point, according to the research.
But the study suggested that such prolonged lockdowns would be unsustainable in most countries due to the potential knock-on effects on the economy and livelihoods.
An international team of researchers from the Global Dynamic Interventions Strategies for Covid-19 Collaborative Group modelled three alternative scenarios across 16 countries, from Belgium to India, that vary in setting and income.
They did not model the scenarios in the UK but said they expect the situation to be "very similar to that in other high-income countries".
Dr Rajiv Chowdhury, a global health epidemiologist at Cambridge University and the paper's lead author, said: "Our models predict that dynamic cycles of 50-day suppression followed by a 30-day relaxation are effective at lowering the number of deaths significantly for all countries throughout the 18-month period.
"This intermittent combination of strict social distancing, and a relatively relaxed period, with efficient testing, case isolation, contact tracing and shielding the vulnerable, may allow populations and their national economies to 'breathe' at intervals - a potential that might make this solution more sustainable, especially in resource-poor regions."
The study indicated that the other two scenarios which were modelled would result in intensive care units being overwhelmed.
The first scenario modelled the impact of imposing no measures.
It indicated a total of 7.8 million deaths across the 16 countries with the epidemic lasting nearly 200 days in most countries.
The second scenario modelled a rolling cycle of looser 50-day mitigation measures followed by a 30-day relaxing.
It indicated 3.5 million deaths and a longer pandemic of around 12 months in high-income countries and 18 months or longer in other settings.
The final scenario, of a rolling cycle of stricter, 50-day suppression measures followed by a 30-day relaxing, would keep intensive care unit demand within capacity in all countries, the research suggested.
It indicated a longer pandemic of more than 18 months in all countries, and more than 130,000 deaths.
Professor Oscar Franco, from the University of Bern in Switzerland, said: "Our study provides a strategic option that countries can use to help control Covid-19 and delay the peak rate of infections.
"This should allow them to buy valuable time to shore up their health systems and increase efforts to develop new treatments or vaccines.
"There's no simple answer to the question of which strategy to choose.
"Countries - particularly low-income countries - will have to weigh up the dilemma of preventing Covid-19-related deaths and public health system failure with the long-term economic collapse and hardship."
