2 jabs of AZ vaccine give zero immunity after 15 weeks to omicron variant, page-20

From the link

"Importantly, protection against severe disease is much higher" for all categories: recently vaccinated, waned, or boosted.

"We estimated that protection against severe disease was 86% for recent mRNA vaccination against Omicron, 67% for waned immunity, and 91% following 3rd dose boosters," Kilpatrick said.

This is a very strong case fir vaccination.