In an ideal world, Omicron survivors wouldn’t have to worry about getting COVID ever again. But because Omicron is still so new, it’s too early to know how well, and how long, immunity from infection will hold up against another bout with the virus, or what scientists call “reinfection.” Prior to Omicron, research suggested that immunity could begin to wane just three months after infection, though it has varied tremendously from person to person. COVID reinfections do occur: People who came down with the virus months ago, before Omicron had even been identified, don’t seem to have strong protection against this variant. (Virtually no one knows which variant they had, but if you got COVID sometime in the past month, it was very likely Omicron.)…

Because people who were fully vaccinated before falling sick with Omicron already have a good level of protection against severe illness, they have more flexibility in what sorts of behaviors they can safely engage in. Though an Omicron infection does lead to an immunity boost, the additional layer of protection provided by an actual booster shot can only help. “The level of COVID that we have out in the community is a level we have not seen anything like in this entire pandemic, so your best level of protection is still to get a booster,” Jodie Guest, an epidemiologist at Emory University, told me. By this logic, people who had two doses of an mRNA vaccine and a booster before getting infected have the best protection of all. “You’ve presented the immune system [with] the spike protein on four different occasions, so that’s likely to generate a very substantial immune response,” Vermund said.