Early Estimates of Bivalent mRNA Vaccine Effectiveness...

This report describes the effectiveness of the updated (bivalent) COVID-19 vaccines for prevention of COVID-19-associated hospitalization among adults ages 65 years or older who did not have a weakened immune system and who were hospitalized with COVID-19-like illness.

Centers for Disease Control and Prevention
Only 1/3 adults over 65 have received the updated bivalent covid booster
This study shows that older adults who received the booster were 70% less likely to be hospitalized for covid than individuals who had received the initial 3 dose series
Getting the bivalent booster substantially reduced severe covid in older individuals