Respiratory Syncytial Virus Vaccine Effectiveness in Older Adults

Age >=60 years as of 2023; exact date of birth is not available in the data source.

• Assignment criteria are met for vaccinated or unvaccinated groups. The individuals will be categorized into groups based on vaccination status at the index date following 01 Aug 2023. The individuals may be in the unvaccinated group prior to becoming vaccinated and indexing into a vaccinated group.

Unvaccinated against RSV: Matched to an *individual in the vaccinated group. The index date will be assigned to the same date as the matched vaccinated individual‘s index date.

• Continuously enrolled with medical and pharmacy benefits for at least 12 months prior to and not including the index date (baseline period) and for at least 14 days after the index date.

Unknown age, sex, insurance type, or state.

• >=1 medical or pharmacy claim with a code for Abrysvo, AREXVY, nirsevimab, or palivizumab during the baseline period. ≥1 medical claim with a diagnosis code for RSV in the 90 days prior to the index date.
• (Vaccinated group only) >=1 medical or pharmacy claim with a code for Abrysvo on the index date through 3 days following the index date (Index to Index+3); these individuals will be excluded due to concerns that these claims may indicate errors in either the AREXVY or Abrysvo claim and lead to a risk of exposure misclassification.