“Most of the differences between Omicron and previous variants are readily explained by people being vaccinated. Even though they’re experiencing breakthrough infections, those are quite different from a primary infection in a few ways:
1. More head-cold symptoms, fewer high fevers and severe respiratory symptoms. The cold symptoms like runny nose are the primed immune system reacting to the early viral replication. T cells are keeping the virus out of the lungs.
2. More negative tests in symptomatic individuals. Because the primed immune system reacts quickly, the infected person may experience symptoms very early. Because the immune system is keeping viral load low (at least for a while), they may continue to test negative, especially on rapid antigen tests.
3. Fewer hospitalizations. A consequence of #1. Even though Omicron sneaks past most of your antibodies, the second line of defense — T cells — remains intact, preventing most organ damage.
There MAY also be differences in the way the virus infects and spreads, but it’s hard to be sure since we haven’t seen how it works in an immunologically naive population. In the mean time, appreciate what our immunity is doing for us, and also be aware that some folks remain susceptible to severe illness. This “mild” wave won’t be mild for everyone, and it’s on all of us to do our part to limit spread.”