Respiratory Virus Transmission Network (RVTN)
The Respiratory Virus Transmission Network (RVTN) is designed to estimate whether vaccines reduce transmission of influenza and COVID-19 within households.
The RVTN uses a case-ascertained household transmission study design. In this study design, households are enrolled by first recruiting a person who tests positive for either influenza or SARS-CoV-2, referred to as an index case, and then enrolling other members in their household.
An index case is eligible for enrollment in this study if they:
- Have tested positive for either influenza or SARS-CoV-2,
- Have had their illness for 5 or fewer days,
- Are likely the first person with illness or infection in the household,
- And live in a non-congregate setting with at least one other person.
Members of the household other than the index case are also eligible.
Once enrolled, the index case and all enrolled household members answer questionnaires about vaccination history, relevant medical history, demographic information, and ways household members interact with one another. They also report on symptoms daily for 7–10 days and self-collect respiratory specimens. The specimens collected from the study are tested for influenza or SARS-CoV-2, depending on the infection of the index case. These test results are used to identify more people in the household who are infected and the risk of secondary infection. The risk of getting infected from index cases who were vaccinated is compared with the risk of being infected from index cases who were not vaccinated; this comparison is used to assess the vaccine effectiveness against transmission. This study design is also used to determine the risk of infection in a vaccinated household member compared with the risk in an unvaccinated household member, which is a secondary objective of RVTN.
To carry out the study, the Respiratory Virus Transmission Network has partnered with Westat and Vanderbilt University.
- Westat is recruiting people who have newly tested positive for influenza or SARS-CoV-2 by national commercial laboratories.
- Vanderbilt University is coordinating with universities and research institutes to recruit people who newly tested positive for influenza or SARS-CoV-2 from outpatient clinics, urgent care clinics, emergency departments, or local testing sites in select areas of seven states/jurisdictions:
- Arizona – University of Arizona
- California – Stanford University
- Colorado – University of Colorado
- New York City – Columbia University
- North Carolina – University of North Carolina
- Tennessee – Vanderbilt University Medical Center
- Wisconsin – Marshfield Clinic Research Institute
Why do we estimate the effectiveness of vaccines against transmission?
While many studies have demonstrated that influenza and COVID-19 vaccines protect the person vaccinated against illness and severe disease, vaccination may also reduce the spread of these viruses; a vaccinated person who becomes infected may or may not be less infectious to others. Knowing whether vaccines reduce transmission helps us understand the full benefits of vaccination. What we learn may guide public health recommendations for the use of vaccines for respiratory viruses.