After Omicron, this pandemic will be different

Every exposure, whether to the virus or a vaccine, reduces the likelihood of severe illness on subsequent ones. That’s because each time our immune systems “see” the spike proteins on the outside of the coronavirus, which is the target for all the vaccines in use, they get better at responding to them. Infections get less severe, on average, over time not just because the virus is changing, but because our bodies are getting better at handling it.

There’s no guarantee that this pattern will continue. Immunity can wane and the virus can evolve to sidestep protection. But all the evidence scientists have seen to date indicates that the protection against severe illness is continuing to hold up. If that does continue, the next round with the virus (and there will be a next round) could be blunted, meaning the impact will be less significant for health care…

Not everyone is equally protected. While immunity gained from prior infection is beneficial for preventing future illness, it is not as beneficial as when combined with vaccination. For unvaccinated people with no immunity to the virus, Omicron can still cause severe disease. Too many people in the United States are unvaccinated. The number of Americans who have received booster shots is also far smaller than it should be, especially for older vulnerable people. This may be in part why the situation in the United States appears worse than in countries like Britain.