Epidemiological data showing that, given the same exposure, the Omicron variant is more likely than other variantes to infect a previously immunized individual (greater “adjusted odds ratio”):
EDIT: I do disagree with the statement “It’s pretty clear that omicron is responsible for a far higher percentage of breakthrough cases than Delta.” I follow specifically the data in the Netherlands, so the statement might be true for a different country. According to the RIVM, in the Netherlands, between 22 November - 19 December 2021, there were 44,368 reported Delta breakthrough infections and only 815 Omicron breakthrough infections. The data suggests that we will see Omicron become dominant over the next few months.
Epidemiological data showing that, given the same exposure, the Omicron variant is more likely than other variantes to infect a previously immunized individual (greater “adjusted odds ratio”):
Eggink, Dirk, et al. “Increased risk of infection with SARS-CoV-2 Omicron compared to Delta in vaccinated and previously infected individuals, the Netherlands, 22 November to 19 December 2021.” medRxiv (2021).
Andeweg, Stijn P., et al. “Increased risk of infection with SARS-CoV-2 Beta, Gamma, and Delta variant compared to Alpha variant in vaccinated individuals.” medRxiv (2021).
Molecular data showing that the neutralizing activity in immunized individuals is lower for Omicron than other variants:
Cameroni, Elisabetta, et al. “Broadly neutralizing antibodies overcome SARS-CoV-2 Omicron antigenic shift.” bioRxiv (2021).
Planas, Delphine, et al. “Considerable escape of SARS-CoV-2 variant Omicron to antibody neutralization.” bioRxiv (2021).
Liu, Lihong, et al. “Striking Antibody Evasion Manifested by the Omicron Variant of SARS-CoV-2.” bioRxiv (2021).
EDIT: I do disagree with the statement “It’s pretty clear that omicron is responsible for a far higher percentage of breakthrough cases than Delta.” I follow specifically the data in the Netherlands, so the statement might be true for a different country. According to the RIVM, in the Netherlands, between 22 November - 19 December 2021, there were 44,368 reported Delta breakthrough infections and only 815 Omicron breakthrough infections. The data suggests that we will see Omicron become dominant over the next few months.