Results
Booster Dose Vaccination Campaign
By October 31, 2021, persons ≥60 years of age reached a vaccination rate of ≈80% (Appendix Figure 1). Vaccination rates by that date were 70.2% for the 50–59-year age group, 62.4% for the 40–49-year age group, 53.1% for the 30–39-year age group, and 44.7% for the 16–29-year age group (Appendix Figure 1).
Booster Dose VE in Persons 16–59 Years of age
Adjusted VE point estimates reached 92.8% (95% CI 91.3%–94.0%) in week 2 of the evaluation period and 96.8% (95% CI 96.0%–97.5%) by week 3 (Figure 2, panel A; Appendix Table 3). The adjusted VE remained above 95% until week 10 and thereafter started to slowly decline, reaching VE of 89.6% (95% CI 85.4%–92.7%) in week 14. In weeks 15 and 16, VE point estimates declined by 12%, reaching a point estimate of 77.6% (95% CI 68.4%–84.2%) (Figure 2, panel A; Appendix Table 3). The evaluation dates of weeks 15 and 16 occurred during December 2021 (Appendix Table 2), when the percentage of the B.1.1.529 (Omicron) variant among reported sequenced samples in Israel rapidly increased (Figure 3).[9] VE estimation by age groups demonstrated similar patterns (Appendix Figure 4).
