A lot of factors are at play, starting with the appearance of the highly contagious omicron variant. Omicron is more likely to infect people, even if it does not cause severe illness, and its outbreak coincided with the holiday travel season in many places.
People may believe that the COVID-19 vaccines will completely prevent infection, but the shots are primarily intended to prevent severe illness, according to Louis Mansky, a virus researcher at the University of Minnesota.
And the vaccines are still doing their job, particularly for those who have gotten boosters.
Two doses of the Pfizer-BioNTech or Moderna vaccines, or one dose of the Johnson & Johnson vaccine, still provide effective protection against serious omicron illness. While the initial doses aren’t very effective at preventing omicron infection, boosters — particularly with the Pfizer and Moderna vaccines — boost antibody levels to help fend off infection.
Omicron appears to replicate at a much higher rate than previous variants. And if infected people have high virus loads, they are more likely to pass it on to others, especially the unvaccinated. Vaccinated people who contract the virus are more likely to have mild symptoms, if any, because the shots activate multiple defenses in your immune system, making it much more difficult for omicron to slip through all of them.
The advice on how to stay safe hasn’t changed. Doctors recommend wearing masks indoors, avoiding crowds, and getting vaccinated and boosted. Even if the shots don’t always keep you from getting the virus, they will increase your chances of survival and out of the hospital.