Efficacy of a Respiratory Syncytial Virus (RSV) Prefusion F Protein Vaccine (RSVPreF3 OA) in Older Adults with Preexisting Medical Conditions

Adults with diabetes and other conditions are at increased risk of severe RSV disease and hospitalization. In a phase 3 placebo-controlled study (NCT04886596) in adults ≥60 years, RSVPreF3 OA showed 82.6% vaccine efficacy (VE) against RSV-related lower respiratory tract disease (RSV-LRTD) and 71.7% against RSV-related acute respiratory infection (RSV-ARI). We assessed VE among participants with different BMI and with selected pre-existing metabolic or endocrine conditions (eg, diabetes) that increase the risk of severe RSV disease. Adults ≥60 years were 1:1 randomized to receive 1 dose of RSVPreF3 OA or placebo before the RSV season. VE against first occurrence of RSV-LRTD and RSV-ARI was calculated for different subgroups (Table). In total, 24,966 participants received RSVPreF3 OA (12,467) or placebo (12,499). Of these, 25.7% (RSVPreF3 OA) and 25.9% (placebo) had ≥1 metabolic or endocrine condition (22.9% diabetes). Mean BMI in both groups was 29.1 kg/m2. In participants with overweight/obesity, VE was 85.6% (RSV-LRTD) and 76.3% (RSV-ARI). In those with ≥1 metabolic or endocrine condition, VE was 100% (RSV-LRTD) and 79.4% (RSV-ARI) (Table). RSVPreF3 OA is highly efficacious against RSV-LRTD and RSV-ARI in adults ≥60 years with overweight/obesity and in those with ≥1 metabolic or endocrine condition.