COVID-19 Vaccination Protects People More So Than Prior Viral Infection
New Study Reports Vaccination Is Especially Protective in People 60+
A new Cedars-Sinai study shows that immunity from vaccination, more than prior illness, protects against repeat infection with the virus that causes COVID-19. This is particularly the case for people age 60 and older.
The findings are published in The Journal of Infectious Diseases.
“Protection provided by infection wanes over time,” said Joseph Ebinger, MD, a clinical cardiologist, director of Clinical Analytics in the Department of Cardiology in the Smidt Heart Institute at Cedars-Sinai, and first author of the study. “These findings show that vaccination is still an important part of the arsenal for protecting people over the long term.”
Investigators tracked infections among 4,496 people who agreed to share serological samples as part of their participation in the study. From December 2021 to December 2022, when the Omicron variant was dominant, the investigators documented 2,053 new-onset infections in this group.
They examined incidence of new infections among people who were either infected less than 90 days prior or whose last known antigenic exposure was either recent (<90 days) or remote (≥90 days) infection or vaccination.
A key part of the study reviewed data from people whose most recent antigenic exposure was more than 90 days prior. For this group, people age 60 and older were significantly more protected by vaccination than prior infection.
“We know from previous studies by our group and others that the combination of prior infection and prior vaccination offers a hybrid immunity,” said Kimia Sobhani, PhD, associate professor of Pathology and Laboratory Medicine at Cedars-Sinai and senior author. “We wanted to understand whether if the last exposure was a long time ago, would it have been better if that last exposure was an infection or if it was a vaccination. Asking the question this way helps us understand if someone might benefit from another vaccination.”
The investigators are continuing to study the factors that can build and maintain immune memory against SARS-CoV-2 infection, even as the virus continues to mutate.
Other Cedars-Sinai investigators who worked on the study include Nancy Sun, MPS; Sandy Y. Joung, MHDS; John Michael S. Sanchez, MD, PhD; Minhao Wang, MPH; Yunxian Liu, PhD; Mallory Heath, MLS; Susan Cheng, MD, MPH; and Kimia Sobhani, PhD.
Funding: The study was funded by the Erika J. Glazer Family Foundation and Sapient Bioanalytics, LLC.