Respiratory syncytial virus vaccine uptake among adults aged ≥60 years in a large, integrated healthcare system in Southern California 2023-2024.

During the 2023-2024 respiratory syncytial virus (RSV) season, vaccination was recommended for adults ≥60 years based on shared clinical decision-making with their healthcare providers. We examined RSV vaccine uptake and characteristics associated with uptake among age-eligible Kaiser Permanente Southern California (KPSC) patients. Our study cohort included all patients ≥60 years from September 23, 2023 (i.e., date RSV vaccination first became available at KPSC; N = 1,003,132) to April 9, 2024 (i.e., end of local RSV season). To identify sociodemographic and clinical characteristics associated with RSV vaccination, we used multivariable robust Poisson regression to estimate the adjusted relative risk (aRR) and 95 % CI. Overall, 7.6 % of patients were vaccinated for RSV. In multivariable regression analyses, those aged 70-79.9 years (aRR: 1.36; 95 % CI: 1.34-1.39) and aged ≥80 years (aRR: 1.35; 95 % CI: 1.32-1.38) were more likely to be vaccinated, compared with those aged 60-69.9 years. Compared with Non-Hispanic White patients, Asian (aRR: 0.95; 95 % CI: 0.93-0.97), Hispanic (aRR: 0.52; 95 % CI: 0.51-0.54), Non-Hispanic Black (aRR: 0.69; 95 % CI: 0.67-0.71), Pacific Islander (aRR: 0.91; 95 % CI: 0.84-0.98), and Native American or Alaska Native (aRR: 0.80; 95 % CI: 0.70-0.92) patients were less likely to be vaccinated. Those in higher neighborhood deprivation quartiles were less likely to be vaccinated (Q2: aRR: 0.86; 95 % CI: 0.85-0.88; Q3: aRR: 0.77; 95 % CI: 0.76-0.79; and Q4: aRR: 0.67; 95 % CI: 0.65-0.68), compared with those in the lowest deprivation quartile. We found low vaccination uptake and identified disparities in vaccination that might exacerbate existing disparities in RSV infection and severe RSV disease among certain populations. CDC's ACIP recently updated their recommendations for all adults 75+ years, and this might begin to address these disparities.