Relative vaccine effectiveness (rVE) against COVID-19 hospitalisation
Relative to complete primary vaccination ≥169 days ago, the first booster rVE for ≥80-years ranged between 52.2% (95%CI: 24.7; 69.6) in April–May 2022 and 45.5% (95%CI: 31.4; 56.7) in October–November 2022. The corresponding estimates for the 65–79-years were 64.2% (95%CI: 42.2; 77.8) and 30.4% (95%CI: 9.8; 46.3), respectively. (Table 2, Figure S1).
Relative to the first booster vaccination ≥90 days ago, the incremental protection conferred by the second booster ranged for the ≥80-years between 54.0% (95%CI: 42.9; 62.9) in June-July 2022 and 34.2% (95%CI: 16.8; 47.9) in September-October 2022 and, for the 65–79-years, from -39.9% (95%CI: -89.3; 3.4) in August-September 2022 to 57.4% (95%CI: 34.6; 72.2) in October-November 2022 (Table 3, Figure S2).