Table 4 Vaccine efficacy of Abrysvo against severe medically attended LRTD caused by RSV in infants from birth through 6 months of age by active immunisation of pregnant individuals between weeks 28 and 36 of gestation – Study 1 a CI = confidence interval; VE = vaccine efficacy a Post-hoc descriptive subgroup analysis was not controlled for multiple comparisons.
Table 5 Vaccine efficacy of Abrysvo against medically attended LRTD caused by RSV in infants from birth through 6 months of age by active immunisation of pregnant individuals between weeks 28 and 36 of gestation – Study 1 a CI = confidence interval; VE = vaccine efficacy a Post-hoc descriptive subgroup analysis was not controlled for multiple comparisons. Active immunisation of individuals 60 years of age and older Study 2 was a phase 3, multicentre, randomised, double - blind, placebo-controlled study to assess the efficacy of Abrysvo in the prevention of RSV - associated LRTD in individuals 60 years of age and older.
RSV - associated LRTD was defined as RT - PCR confirmed RSV disease with two or more or three or more of the following respiratory symptoms within 7 days of symptom onset and lasting more than 1 day during the same illness: new or increased cough, wheezing, sputum production, shortness of breath or tachypnoea (≥25 breaths/min or 15% increase from resting baseline). Participants were randomised (1:1) to receive Abrysvo (n=18 487) or placebo (n=18 479). Enrollment was stratified by age 60-69 years (63%), 70-79 years (32%) and ≥80 years (5%).
Subjects with stable chronic underlying conditions were eligible for this study and 52% of participants had at least 1 prespecified condition; 16% of participants were enrolled with stable chronic cardiopulmonary conditions such as asthma (9%), chronic obstructive pulmonary disease (7%) or congestive heart failure (2%). Immunocompromised individuals were ineligible. The primary objective was assessment of vaccine efficacy (VE), defined as the relative risk reduction of first episode of RSV-associated LRTD in the Abrysvo group compared to the placebo group in the first RSV season.
Of the participants who received Abrysvo, 51% were male and 80% were White, 12% were Black or African American and 42% were Hispanic/Latino. The median age of participants was 67 years (range 59-95 years). At the end of the first RSV season the analysis demonstrated statistically significant efficacy for Abrysvo for reduction of RSV-associated LRTD with ≥2 symptoms and with ≥3 symptoms. Vaccine efficacy information at the end of the first RSV season (median follow-up time 7.4 months) is presented in Table 6.
8 Time period Abrysvo Number of cases N=2 602 Placebo Number of cases N=2 609 VE % (95% CI) 90 days 2 22 90.9 (62.9, 99.0) 120 days 5 31 83.8 (58.0, 95.1) 150 days 6 38 84.2 (62.3, 94.5) 180 days 8 43 81.3 (59.9, 92.4) Time period Abrysvo Number of cases N=2 602 Placebo Number of cases N=2 609 VE % (95% CI) 90 days 18 43 58.0 (25.7, 77.2) 120 days 25 61 58.9 (33.6, 75.3) 150 days 30 76 60.4 (38.9, 75.0) 180 days 35 90 61.0 (41.8, 74.4)