While it is difficult to know how endemic coronavirus will manifest, there are two important characteristics worth monitoring in the coming months and years: the frequency and severity of outbreaks. These two factors will delineate the disruption caused by the coronavirus going forward.

The future frequency of coronavirus outbreaks is strongly linked to population immunity and how the virus changes. A population’s resistance to circulating variants depends on people’s history of infection, vaccination and boosting. Variants with only minor differences from a vaccine formulation or an older variant may not produce much disease. However, a variant with substantive changes — such as Omicron — may infect many people by evading immunity. This winter, many people who had good protection against Delta, the variant that Omicron displaced, were still susceptible to infection and disease from Omicron.

A big unknown is whether SARS-CoV-2 can continue to produce variants that skirt around the immune system like Delta and Omicron. If the virus has this capacity, outbreaks could occur several times a year, much like during 2021. This endemic pattern might hold for a few more years or indefinitely. On the other hand, if the capacity to produce highly immune evasive variants is tapped out, future versions of the virus might be less aggressive and produce fewer outbreaks, perhaps once a year during winter, much like the flu.