Table 1.

Potential COVID-19 lockdown exit strategies

Strategy	Description	Pros and cons	Countries	Supporting evidence
Natural herd immunity	Depending on the true R0, this would require between approximately 58%-82% of the population to recover from infection with sufficient levels of antibodies to achieve herd immunity.	Pros: Maintains societal functioning.	Sweden	[10]
		Cons: Reliant on the assumption that long-term immunity is possible despite some evidence of possible reinfections. Large number of deaths in elderly and the vulnerable (akin to ‘survival of the fittest’). Need to stay within health services capacity. Social unrest if individuals unable to access medical services.
Lockdown till cure or vaccination herd immunity	This option maintains the lockdown indefinitely until a therapeutic is found or a vaccine has been developed, tested, mass-produced and deployed at sufficient levels to achieve herd immunity.	Pros: If maintained, highly likely to prevent transmission.	Current default for many countries
		Cons: Highly unlikely to be maintainable given social, health & economic consequences. Furthermore, no guarantee that a therapeutic or vaccine will be found.
Attempt to eliminate the virus	The “test, trace, isolate” strategy advocated by WHO, which aims to fully contain and suppress the epidemic and then reopen society.	Pros: WHO advocated approach with some evidence of success. Keep society and economy running by just removing those carrying virus and breaking chains of transmission.	China, Czech Republic, Faroe Islands, Germany, Iceland, Singapore, South Korea, Vietnam, Greece, New Zealand, Australia	[11]
		Cons: Insufficient surveillance, testing, tracing and isolating capability in the UK. Need for border control to catch imported cases.		[12]
Containment measures (many of which are likely to be used in combination):
Gradual release	Gradual release of lockdown restrictions informed by the areas which are responsible for most economic productivity whilst still being able to adhere to physical distancing measures (eg, construction workers). Needs close monitoring of the number of new cases generated as a result of the release, which would inform whether further loosening or tightening of restrictions is required.	Pros: Allows an assessment of what impact lockdown relaxation measures are having.	Austria, Czech Republic, Denmark, Germany, Italy, Ireland, Norway, Spain	[13]
				[14]
		Cons: May result in actual or perceived inequity leading to social unrest.		[15]
Population scheduling	Splits the population into groups and only allows these groups out at certain days/times. This can allow for the resumption of economic activity whilst helping to maintain physical distancing.	Pros: Allows an assessment of what impact lockdown relaxation measures are having.	Panama; being considered in Croatia, Peru and Spain	[16]
		Cons: May result in actual or perceived inequity leading to social unrest.
Geographical segmentation	Involves dividing the country into distinct geographical regions and implementing strategies at these regional levels. Could be used selectively to isolate hot spots to prevent widespread transmission through strict enforcement of lockdown measures. Conversely, areas with low transmission would be free to travel within their geographical boundaries.	Pros: Allows an assessment of what impact lockdown relaxation measures are having.	Argentina, Australia, China, Germany, Israel, Italy, Kuwait, Russia, Saudi Arabia, UAE	[17]
		Cons: May result in actual or perceived inequity leading to social unrest. Could lead to movement within countries towards regions with less restrictive policies.		[18]
PPE for the general public	Strongly encouraging or mandating the wearing of PPE in public spaces such as face masks.	Pros: May offer some protection against transmission in areas where physical distancing cannot be maintained such as public transport, shops and workplaces.	China, Singapore South Korea, Scotland, UAE US	[19]
		Cons: Global PPE shortage so may divert essential supplies from the front-line. Face masks should be home-made and cloth-based		[20]

ICU-Intensive care unit, PPE-Personal protective equipment, R₀ – basic reproduction number, R_t – effective reproduction number, UAE-United Arab Emirates, USA – Unites States of America, WHO – World Health Organization