What to know
The Respiratory Virus Transmission Network for Influenza (RVTN-Flu) was designed to estimate how influenza (flu) spreads within households and whether vaccines reduce transmission of flu. This study also examined how influenza vaccination changes the risk of infection in households. RVTN enrollment ended in May 2025. This page is for historical purposes and provides background about the RVTN-Flu study and how its findings support ongoing public health work.
Background
The RVTN-Flu used an enhanced case-ascertained household transmission study design. In this approach, households were enrolled by first recruiting a person who tested positive for influenza; this person was referred to as an index case. The other members of the index case's household were also enrolled.
Participants self-collected daily nasal swab specimens for influenza testing over a 7-day period. They also logged daily illness symptoms and answered questions about vaccination history, relevant medical history, demographic information, and ways in which household members interacted with one another. These daily logs and specimens were used to estimate how often flu spreads within households, how often people get infected without symptoms, and how vaccination may help reduce spread. A 30-day follow-up survey captured information on how long people were sick, how severe their symptoms were, and whether they needed medical care.
NOTE: RVTN-Flu enrollment ended May 2025.
Participating sites
To carry out the study, RVTN-Flu collaborated with Washington University School of Medicine, Vanderbilt University Medical Center, and Columbia University Irving Medical Center. Each participating site used an existing network of walk-in-clinics, outpatient clinics, and emergency departments with integrated testing to identify patients who had recently tested positive for influenza infections.
Previous Respiratory Virus Transmission Network (RVTN) efforts included collaborations with other academic partners including, Marshfield Clinic Research Institute, University of North Carolina, University of Colorado, University of Arizona, and Stanford University.