RSV Vaccine Efficacious for Older Adults Regardless of Underlying Conditions

A single dose of an AS01_E-adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based candidate vaccine (RSVPreF3 OA) was safe and efficacious for older adults regardless of RSV subtype and patients' underlying conditions. Researchers published their findings in The New England Journal of Medicine.

“[RSV] is an important cause of acute respiratory infection, lower respiratory tract disease, clinical complications, and death in older adults. There is currently no licensed vaccine against RSV infection,” researchers said.

In the ongoing phase 3 trial, 24,966 participants aged at least 60 years were randomized to receive either the RSVPreF3 OA vaccine or placebo. Using reverse-transcriptase polymerase chain reaction tests to confirm infections, researchers assessed the vaccine’s efficacy for preventing RSV-related lower respiratory tract disease during the RSV season.

At a median follow-up of 6.7 months, the RSVPreF3 OA vaccine was 82.6% efficacious for preventing RSV-related lower respiratory tract disease (96.95% confidence interval [CI], 57.9 to 94.1). Researchers identified 7 cases (1.0 per 1000 participant-years) in the vaccine group and 40 cases (5.8 per 1000 participant-years) among those who received placebo.

The vaccine was 94.1% efficacious against severe cases of RSV-related lower respiratory tract disease (95% CI, 62.4 to 99.9). Findings indicate the vaccine was also 71.7% efficacious for preventing RSV-related acute respiratory infection (95% CI, 56.2 to 82.3).

“High vaccine efficacy was observed in various age groups and in participants with coexisting conditions,” researchers advised.

The vaccine’s efficacy also did not vary significantly depending on RSV subtype.

“The RSVPreF3 OA vaccine was more reactogenic than placebo, but most adverse events for which reports were solicited were transient, with mild-to-moderate severity. The incidences of serious adverse events and potential immune-mediated diseases were similar in the two groups,” researchers said.

The investigators concluded the RSVPreF3 OA vaccine successfully prevented RSV-related acute respiratory infection, lower respiratory tract disease, and severe lower respiratory tract disease in older adults.

Reference:
Papi A, Ison MG, Langley JM, et al. Respiratory syncytial virus prefusion F protein vaccine in older Adults. N Engl J Med. 2023;388(7):595-608. doi:10.1056/NEJMoa2209604