It's happening at UC Davis Health. The volunteers are the same people who participated in the first Pfizer trials last summer, They'll be receiving the identical vaccine.
One thing scientists will look at is how strong the antibodies are 6-to-8 months after those first shots.
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"We're actually going to be measuring antibodies to COVID," said Dr. Timohy Albertson of UC Davis Health, "We've got their baseline. We got their baseline when they started naively last July. We've got their response to the therapy."
Researchers believe that over time, a person's immune system forgets the vaccination.
They're hoping to track how much time passes before someone needs another dose.
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CDC COVID-19 Transmission Levels by U.S. County
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