Table 6 Vaccine efficacy of Abrysvo against RSV disease - active immunisation of individuals 60 years of age and older – Study 2 CI – confidence interval; RSV – respiratory syncytial virus; VE – vaccine efficacy N = number of participants; n = number of cases a In an exploratory analysis in RSV subgroup A (Abrysvo n=3, placebo n=16) VE was 81.3% (CI 34.5, 96.5); and in RSV subgroup B (Abrysvo n=12, placebo n=26) VE was 53.8% (CI 5.2, 78.8). b In an exploratory analysis in RSV subgroup A (Abrysvo n=1, placebo n=5) VE was 80.0% (CI -78.7, 99.6); and in RSV subgroup B (Abrysvo n=1, placebo n=12) VE was 91.7% (CI 43.7, 99.8).
Vaccine efficacy in the subgroup of participants 80 years of age and older (995 and 981 participants in the Abrysvo and placebo groups, respectively) cannot be concluded due to the low number of total cases accrued (7 cases of RSV-associated LRTD with ≥2 symptoms and 3 cases of RSV-associated LRTD with ≥3 symptoms).
Efficacy against RSV-associated lower respiratory tract disease over 2 RSV seasons in individuals 60 years of age and older Across 2 RSV seasons with median follow-up time of 16.4 months, VE against RSV-associated LRTD with ≥2 symptoms was 58.8% (95% CI 43.0, 70.6; 54 cases in the Abrysvo group and 131 cases in the placebo group) and with ≥3 symptoms was 81.5% (95% CI 63.3, 91.6; 10 cases in the Abrysvo group and 54 cases in the placebo group).
VE against RSV-associated LRTD caused by RSV-A and RSV-B was 66.3% (95% CI 47.2, 79.0) and 50.0% (95% CI 18.5, 70.0) for cases with ≥2 LRTD symptoms respectively, and 80.6% (95% CI 52.9, 93.4) and 86.4% (95% CI 54.6, 97.4) for cases with ≥3 LRTD symptoms, respectively. Across 2 RSV seasons, subgroup analyses of VE by age and significant underlying conditions were consistent with VE at the end of the first RSV season and support consistent VE across different age and risk groups.
Immunogenicity in individuals 18 through 59 years of age Study 3 was a Phase 3, multicentre, randomised, double-blind, placebo-controlled study to assess the safety and immunogenicity of Abrysvo in individuals 18 through 59 years of age considered to be at high risk of developing severe LRTD caused by RSV. Study 3 enrolled individuals who had chronic pulmonary (including asthma), cardiovascular (excluding isolated hypertension), renal, hepatic, neurologic, haematologic or metabolic disorders (including diabetes mellitus and hyper/hypothyroidism). Participants were randomised (2:1) to receive a single dose of Abrysvo (n=437) or placebo (n=217).
Demographic characteristics in study 3 were generally similar with regard to age, race and ethnicity among participants who received Abrysvo and those who received placebo. Fifty-three percent (53%) were 18 to 49 years and 47% were 50 to 59 years.
The vaccine and placebo groups were similar with 9 Efficacy endpoint Abrysvo Placebo VE (%) (95% CI) N n N n First episode of RSV- associated LRTD with ≥2 symptomsa Overall 18 058 15 18 076 43 65.1 (35.9, 82.0) Age 60-69 years 11 305 10 11 351 25 60.0 (13.8, 82.9) Age 70-79 years 5 750 4 5 742 12 66.7 (-10.0, 92.2) With ≥1 significant underlying condition 9 377 8 9 432 22 63.6 (15.2, 86.0) First episode of RSV- associated LRTD with ≥3 symptomsb Overall 18 058 2 18 076 18 88.9 (53.6, 98.7) Age 60-69 years 11 305 2 11 351 11 81.8 (16.7, 98.0) Age 70-79 years 5 750 0 5 742 4 100 (-51.5, 100.0) With ≥1 significant underlying condition 9 377 2 9 432 11 81.8 (16.7, 98.0)