Marshfield Clinic Research Institute continues to support real-time COVID-19 vaccine effectiveness data as the sole reference laboratory in the nation by supporting several Centers for Disease Control and Prevention (CDC)-led studies.

This included a published article in the New England Journal of Medicine in March that showed mRNA vaccines to be 91% effective after the second dose against SARS-CoV-2, and 81% after the first dose. As the Delta variant took grasp of the U.S., our lab helped show that mRNA vaccine effectiveness dropped to 66% by August 2021.

“While vaccine effectiveness against the delta variant has declined, the vaccine remains very effective against hospitalization. This should provide reassurance to clinicians and the public of the value of COVID-19 vaccination," said Jennifer Meece, Ph.D., Director of the Research Institute's Integrated Research and Development Laboratory. “This change in vaccine effectiveness is one of the reasons the CDC is now recommending a booster dose for specific risk groups."

The Research Institute’s role

The Research Institute received a $22.5 million grant from CDC ​in July 2020 and an additional grant for nearly $20 million in June 2021 to play a leading role in a number of COVID-19 studies across the U.S. The Research Institute now tests about 6,000 samples a week, including about 4,000 samples from health care personnel, first responders and other frontline and essential workers from across the U.S. These studies demonstrated in real world conditions the effectiveness of mRNA vaccines in both symptomatic and asymptomatic COVID-19 infections.

The Research Institute's role in these studies 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.

The vaccine effectiveness studies 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, effectiveness of booster vaccines, and the protection against infection with other SARS-CoV-2 variants as those inevitably arise.

The team will also continue to play an important part in the publications resulting from this work. For instance, Meece and senior research associates Lynn Ivacic and Elisha Stefanski helped analyze the results and write the report for the published article in the New England Journal of Medicine.

“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 Dr. Susan Turney, Health System CEO. “Our physician researchers and scientists are dedicated to helping end this pandemic for the people in rural Wisconsin and across the globe."

These vaccine effectiveness study results are encouraging, but the pandemic continues as variants spread.

​“Throughout history, we've seen vaccinations help minimize 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 eligible to get the vaccine."