A single dose of the respiratory syncytial virus (RSV) prefusion F protein vaccine confers sustained protection against RSV-associated lower respiratory tract infection (LRTI) in older adults, including those with underlying comorbidities. These study results were presented at IDWeek 2023, held from October 11 to 15, in Boston, Massachusetts.
The United States Food and Drug Administration (FDA) has approved the RSV prefusion F protein vaccine for the prevention of RSV-associated LRTI in in adults aged 60 years and older.
To evaluate the persistence of vaccine efficacy (VE) conferred by a single dose of the RSV vaccine over 2 RSV seasons in adults aged 60 years and older, researchers conducted a phase 3, multinational, placebo-controlled trial (ClinicalTrials.gov Identifier: NCT04886596). The researchers also assessed the VE and safety of annual RSV vaccination.
Study participants (N=24,967) were randomly assigned 1:1 to receive either the RSV vaccine (n=12,469) or placebo (n=12,498) prior to the start of an RSV season (season 1). Single-dose vaccine recipients from season 1 were then randomly assigned again to receive either a second dose (n=6242) or placebo (n=6227) prior to the start of a second RSV season (season 2). Participants initially assigned to the placebo group also received placebo before season 2.
“
Revaccination after 1 year does not appear to confer additional efficacy benefit for the overall population.
The VE of a single RSV vaccine dose against RSV-associated LRTI over 2 seasons was 67.2% (97.5% CI, 48.2-80.0). Among revaccinated participants, similar VE was observed (67.1%; 97.5% CI, 48.1-80.0). Moreover, the RSV vaccine also demonstrated sustained VE against severe RSV-associated LRTI.
Further analysis was performed to evaluate VE by age and baseline comorbidities. Comorbidities of interest were asthma, chronic respiratory disease, chronic heart failure, diabetes, and advanced liver disease. Results showed sustained protection against RSV-associated LRTI among participants aged 60 to 69 years (VE, 65.4%), those aged 70 to 79 years (VE, 74.9%), those with at least 1 comorbidity (VE, 66.7%), and those who were prefrail (73.3%).
Sustained protection against RSV-associated acute respiratory illness was also observed, though VE was lower for single-dose vs annual revaccination (VE, 52.7% vs 60.3%).
Both reactogenicity and safety profiles were similar between participants who received single-dose vaccination and those who were revaccinated after 1 year.
“Revaccination after 1 year does not appear to confer additional efficacy benefit for the overall population,” the researchers noted. “The clinical development program will further evaluate persistence and the best timing for revaccination,” the researchers concluded.
This article originally appeared on Infectious Disease Advisor.
