DAVIS (CBS13) – As COVID-19 cases increase, local researchers are digging into the impact of a vaccine booster shot. UC Davis Health doctors are putting a third shot to the test.

Some of the first to roll up their sleeves are now ready to do it again as UC Davis Health researches the impact of a third dose of the COVID-19 vaccine.

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“It is a wiley beast that is not going to go away by just wishing it. We did not get herd immunity despite our best efforts,” said Dr. Timothy Albertson, UC Davis Health Internal Medicine distinguished professor and Chair.

Dr. Albertson, who is leading the latest clinical trial, says this is the long haul for a disease that has been mutating quickly. The trial will use the same Pfizer vaccine used in the initial vaccine.  Dr. Albertson says there were additional vaccines to consider and even discussion about one that might be a higher affinity for some of the variants. But instead, this clinical trial will be a continuation of the Pfizer vaccine trial that started about a year ago — with a portion of those who participated now randomly getting a booster or a placebo.

“We’re actually going to be measuring antibodies to COVID. We’ve got their baseline, we’ve got their response to the therapy,” said Dr. Albertson.

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By analyzing all that data, researchers can track how much time passes before someone needs another dose. Over time, your immune system forgets the initial vaccination.

Some people have yet to get the shot at all, which Dr. Albertson says is putting everyone at risk of the virus aggressively mutating even more.

“There are people out there who won’t get the original, let alone the booster. That’s the part I don’t understand…The risk, benefit ratio is so clear,” said Dr. Albertson.

This is all part of a huge study of 40,000 patients worldwide, with volunteers who were carefully chosen.

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UC Davis Health was picked because of the diverse pool of volunteers and their willingness to give feedback and follow-up information.