Neutralizing antibody activity against all variants of SARS-CoV-2, including Delta, lasted 6 months in people who got 2 doses of the COVID-19 mRNA vaccine made by Moderna Inc. The findings were published Aug. 12 in Science magazine.
The study, led by scientists from the National Institute of Allergy and Infectious Diseases and the Emory University School of Medicine, concludes: “While additional studies will be needed to address the impact of new variants that will surely arise in areas of intense viral infection, our data are encouraging for the use of this vaccine in the face of viral variation.”
The research involved multiple tests to measure different types of antibody response and whether they functioned against new virus variants. Blood samples from 24 vaccinated people were drawn multiple times after vaccination. Most participants, including those over 71 years old, had functional antibodies at 6 months after the second dose.
The study addresses a gap in the research. While other studies have performed tests on vaccinated individuals’ blood, most involved samples taken shortly after the first or second dose but not later. And while prior clinical studies have reported somewhat reduced efficacy and effectiveness against the Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2) variants, “they have not fully addressed the durability of cross-reactive binding and functional antibodies,” the paper notes.
The randomly selected samples came from volunteers divided evenly among 3 age groups: 18-55, 55-70, and 71+ years of age. All had samples available from 4 timepoints: 4 weeks after the first dose, and 2 weeks, 3 months, and 6 months after the second dose (Days 29, 43, 119, and 209 after the first dose, respectively).
Lisa Jackson, MD, MPH, a senior investigator at Kaiser Permanente Washington Health Research Institute, is one of the study co-authors. In addition to NIAID, Emory medical school, and KPWHRI, the other co-authors are from Moderna and Emmes Company.
“This study again demonstrates the invaluable research made possible by the National Institutes of Health and the vaccine research consortium it established several decades ago,” Dr. Jackson said. “Kaiser Permanente Washington Health Research Institute is honored to be a part of it and looks forward to continuing to produce work to bring this pandemic under control.”
Following the study’s publication, the Associated Press reported on Aug. 18 that U.S. health authorities are recommending a booster vaccination for most people 8 months after they had received their second vaccine.
The story above is adapted by Jonathan Rabinovitz from a thread of posts on Twitter published by NIAID on Aug. 12.
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