A study out of Denmark shows that compared to the Delta variant, Omicron is far more likely to infect people who are “fully vaccinated” and boosted than those who are unvaccinated. The study looked at 11,937 Danish households during the month of December 2021.

In all, 2,225 people were identified as being infected with Omicron. During a seven-day follow-up period, they also identified 6,397 secondary infections. Interestingly, infection with Omicron was more likely to result in a secondary infection than the Delta strain, and the COVID-jabbed were far more likely to get these secondary infections. As reported by the authors:

“The SAR [secondary attack rate] was 31% and 21% in households with the Omicron and Delta VOC [variant of concern], respectively. We found an increased transmission for unvaccinated individuals, and a reduced transmission for booster-vaccinated individuals, compared to fully vaccinated individuals.

Comparing households infected with the Omicron to Delta VOC, we found a 1.17 (95%-CI: 0.99-1.38) times higher SAR for unvaccinated, 2.61 times (95%-CI: 2.34-2.90) higher for fully vaccinated and 3.66 (95%-CI: 2.65-5.05) times higher for booster-vaccinated individuals, demonstrating strong evidence of immune evasiveness of the Omicron VOC.

Our findings confirm that the rapid spread of the Omicron VOC primarily can be ascribed to the immune evasiveness rather than an inherent increase in the basic transmissibility.”

So, in summary, compared to Delta infection, unvaccinated people were on average 1.17 times more likely to develop a secondary infection when infected with Omicron, while the risk for secondary infections among the triple-jabbed who got Omicron was two to five times greater. In other words, while the unvaccinated had higher transmission rates, they were less likely to succumb to more serious health complications.

SARS-CoV-2 Omicron VOC Transmission in Danish Households

Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study