COVID-19 vaccine efficacy study has added RSV, flu testing

Researchers seek to recruit 3,500 children and adults in the Pacific Northwest to assess how well vaccines protect against COVID-19.

Media Contact: Susan Gregg,

Pacific Northwest researchers are enrolling 3,500 children and adults to participate in a study to assess how well COVID-19 vaccines protect against infection in the community. The study will also look at the rates of respiratory syncytial virus (RSV) and influenza, commonly called the flu.

The CASCADIA study is being led jointly by the University of Washington School of Medicine in Seattle and the Kaiser Permanente Center for Health Research in Portland, Oregon. The study is funded by the U.S. Centers for Disease Control and Prevention.

Individuals aged 6 months to 49 years will be included in the study. The primary goal of this research is to assess how well COVID-19 vaccines protect children aged 5 to 18 years.

Researchers also will be looking at infections among all participants, young and old, vaccinated and unvaccinated, to better understand the role that variants of the SARS-CoV-2 virus have in infection and the effects of risk factors, such as age, health status, and household characteristics. Testing will also be done for flu and RSV.

“This information is vital for understanding how long vaccines in the community work over time and when booster vaccines will be necessary,” said Dr. Helen Y. Chu, associate professor of medicine at the UW School of Medicine. She co-leads the study with Allison Naleway, associate director of Science Programs at Kaiser Permanente Center for Health Research.

In the study, vaccinated and unvaccinated participants will be followed for up to four years for SARS-CoV-2 infection and other respiratory infections including flu and RSV. During this time, they will be tested weekly for SARS-CoV-2, flu, and RSV infection with at-home nasal swab kits. The children will be swabbed by their parents; adults will self-administer the tests. In addition, participants will complete weekly symptom surveys either online or over the phone.

Vaccinations will not be given through the study. Adult enrollment is not required for children in the same family to enroll in the study.

"The bivalent booster vaccines have now been authorized for persons 6 months and older,” said Dr. Janet Englund, an infectious disease specialist at Seattle Children’s and professor of pediatrics at the UW School of Medicine.

“Families who enroll in this study will get free testing for COVID-19, flu, and RSV with immediate results on a weekly basis,” added Englund, who is a co-investigator for the study. She is leading the research at Seattle Children’s.

Blood samples to test for SARS-CoV-2 antibodies will be collected at the beginning of the study, annually, and after vaccinations and infections. These samples will not only confirm whether an illness is due to SARS-CoV-2 but also help researchers understand how the immune system responds to vaccination, infection, and repeat infections.

Researchers will sequence the genome of viruses they isolate to see whether there are genetic differences between the variants that cause infections in unvaccinated participants, breakthrough infections in the vaccinated, and reinfections in the previously infected.

“The COVID-19 vaccines that have been approved in the U.S. have already shown high levels of safety and effectiveness,” said Naleway. “However, we need to continue studying vaccine effectiveness, particularly with new emerging variants of SARS-CoV-2.”

Individuals interested in participating in the study may do so by visiting

For details about UW Medicine, please visit

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