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Marshfield Clinic Research Institute is primary lab in CDC’s COVID-19 vaccine effectiveness study among frontline workers, first responders

March 29, 2021​

MARSHFIELD – Marshfield Clinic Research Institute, the research division of Marshfield Clinic Health System, was the sole reference laboratory in the nation to support the Centers for Disease Control and Prevention (CDC)-led study released today that shows mRNA vaccines to be 90% effective after the second dose against SARS-CoV-2, and 80% after the first dose.

The Research Institute, which received a $22.5 CDC million grant in July 2020 to play a leading role in a number of COVID-19 studies across the U.S., tested 3,950 samples each week for 13 consecutive weeks from health care personnel, first responders and other frontline and essential workers from across the U.S. The study demonstrated in real world conditions the effectiveness of mRNA vaccines in both symptomatic and asymptomatic COVID-19. 

Study link:  

"Our study participants are at an increased risk of COVID-19 as a result of their workplace exposure to patients, co-workers and/or the public," said Jennifer Meece, Ph.D., Director of the Research Institute's Integrated Research and Development Laboratory. "The study showed the vaccine is effective and should provide reassurance to clinicians and the public of the preventive value of COVID-19 vaccination."

Meece and senior research associates at the Lab, Lynn Ivacic and Elisha Stefanski, were among the authors of Monday's report of this first-of-its-kind study.

The Research Institute's role in the study was testing the specimens, which came from participants who self-swabbed and mailed them to Marshfield. Some of the participants expressed their appreciation for the study by including personal notes and drawings for the researchers. Meece, Ivacic and Stefanski also assisted by helping analyze the results and write the report.

Monday's vaccine effectiveness study is an interim analysis and will continue to be updated, much like annual national influenza vaccine studies in which the Research Institute participates. Future updates may address the effectiveness of newer COVID-19 vaccines, including single dose vaccines, and the protection against infection with SARS-CoV-2 variants as those inevitably arise.

This was the first of many COVID-19-related studies the Research Institute will help publish in the coming months as a result of the $22.5 million grant and subsequent grants.

"Marshfield Clinic Research Institute has proven throughout its long history to be a leader in emerging science and disease studies through its work with genomic sequencing, influenza vaccine effectiveness and now COVID-19," said Marshfield Clinic Health System CEO Dr. Susan Turney. "Our physician researchers and scientists are dedicated to helping end this pandemic for the people in rural Wisconsin and across the globe."

The vaccine effectiveness study results are encouraging, but the pandemic continues as the vaccine supply is still limited and variants spread.

"Throughout history, we've seen vaccinations help eradicate diseases like polio and measles," Meece said. "The COVID-19 vaccines went through thorough and rigorous trials and were determined to be effective and safe. We strongly encourage everyone to get the vaccination once they are eligible under state of Wisconsin criteria."

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