Randomized Assessment of Influenza Vaccine Efficacy Network (RAIVEN)

The Randomized Assessment of Influenza Vaccine Efficacy Network (RAIVEN) is a research collaboration between CDC, Westat, and multiple sites in the United States to conduct randomized trials to evaluate how well different influenza vaccines protect people 18-64 years old against influenza (flu).  RAIVEN strives to use innovative research methods to make influenza clinical trials more accessible to US communities with a focus on including populations that have been under-represented in vaccine trials in the past.

Starting in Spring 2022, RAIVEN will conduct a pilot study to evaluate different methods of participant recruitment and enrollment and test influenza surveillance methods among pilot study participants.  RAIVEN aims to launch the full influenza vaccine trial in Fall 2022 at the start of the 2022-23 influenza season. The full trial will enroll participants and randomly assign them to receive either a standard dose egg-based influenza vaccine or an alternative licensed influenza vaccine as part of the study.  The purpose of randomly assigning participants to receive a specific vaccine is to reduce differences between the participant groups who receive the two study vaccines to allow for a more valid comparison of influenza infection rates and other outcomes between the two group.  Additional information about the full trial design will be available in Fall 2022.

Flu Vaccine Efficacy and Effectiveness

Measuring flu vaccine efficacy and vaccine effectiveness (VE) are important to better understand how well flu vaccines protect against flu. Vaccine efficacy refers to how well vaccines protect people against infection in clinical trial research studies that randomly assign participants to receive specific vaccines.  Vaccine effectiveness refers to how well vaccines protect people in real-world studies in which vaccines are not randomly assigned to people.

CDC measures VE each year to evaluate the benefits of flu vaccines in different age groups and against different clinical outcomes.  The RAIVEN study will complement these VE estimates by comparing influenza vaccine efficacy between selected influenza vaccines. These efforts inform US vaccine recommendations and policy decisions aimed at providing the best protection from flu and its potentially serious complications.

Pilot Study Sites and Pilot Study Design

Participating pilot study sites are located in 4 states

  • Arizona
  • Florida
  • Virginia

Study collaborators for the RAIVEN trial will be identified by Fall 2022.

Other Information on CDC Vaccine Effectiveness (VE) Estimates