Why are so many vaccinated people taking COVID-19 lately?

A couple of factors are involved, starting with the emergence of the highly contagious omicron variant.

Omicron is more likely to infect people, even if it doesn’t make them very sick, and its sharp rise has coincided with the holiday travel season in many places.

People may mistakenly think that COVID-19 vaccines will completely block the infection, but the shots are primarily designed to prevent severe disease, says Louis Mansky, a virus researcher at the University of Minnesota.

And vaccines are still doing their job on that front, particularly for people who have got boosters.

Two doses of Pfizer-BioNTech or Modern vaccines or one dose of Johnson & Johnson vaccine still offer strong protection against serious omicron disease. While those initial doses are not very good at blocking omicron infection, boosters – particularly with Pfizer and Moderna vaccines – raise antibody levels to help fight the infection.

Omicron seems to replicate much more efficiently than previous variants. And if infected people have high virus loads, they are more likely to pass it on to others, especially those who are not vaccinated. People vaccinated against the virus are more likely to have mild symptoms, if any, as the triggers trigger various defenses in your immune system, making it much harder for the omicron to slip through them all.

Tips for staying safe have not changed. Doctors say wearing masks inside, avoiding crowds and getting vaccinated and boosted. Even if the shots will not always stop you from catching the virus, they make you much more likely to stay alive in and out of the hospital.