Ideal Properties of a Universal Coronavirus Vaccine.^*

Individual Protection

Necessary

Prevents clinical disease

Prevents infection by all sarbecoviruses and merbecoviruses

Prevents infection by viral drift and recombination variants

Elicits a rapid and robust immune response

Does not have limited vaccine immunogenicity in persons with preexisting immunity

Induces immunity to multiple viral components

Is safe and acceptable to the public

Is safe for pregnant women

Does not induce antibody-dependent enhancement with subsequent wild-type virus exposure

Can be used in persons of all ages

Desirable

Is highly efficacious in one dose

Induces robust lifelong systemic immunity

Induces robust lifelong mucosal immunity

Induces a boost in immunity with subsequent wild-type virus exposure

Does not alter the respiratory microbiome

Is affordable and can be used in low-income countries

Is efficacious in persons with immunosuppression

Community Protection

Necessary

Covers all sarbecoviruses and merbecoviruses

Covers all endemic human coronaviruses

Can be used for pandemic prevention

Is based on a platform that is easily upgraded with new antigens

Desirable

Prevents transmission

Reduces or shortens viral shedding

Creates durable herd immunity

Does not elicit neutralization escape mutants

Is stable in storage

Induces a boost in immune protection with sequential vaccination

^*The features listed describe a truly universal vaccine, although current vaccine approaches are unlikely to achieve all these goals. The highest priority should be universal coverage of betacoronaviruses, with additional coverage of endemic and other coronaviruses.