"It's not where we want to be," said SFDPH's Deputy Director of Health, Dr. Naveena Bobba. "We want those percentages to be well above 50 percent."
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Bobba says all seniors, anyone 65 years and older are eligible for a third booster dose if they are at least six months out from their primary vaccination series.
"It is extremely important for those that are high risk for COVID to get their booster shot as well as their flu shot as they head into the holiday season," she said.
San Francisco has more than 100 vaccination sites across the city and county - including health centers, pharmacies, and hospital systems. Bobba says many of them saw little demand for a third dose over the past few weeks - citing mixed messaging on boosters may be partially to blame. The critical third dose now considered necessary as more research highlights concerns over waning immunity of the vaccine.
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"The research is showing months out immunity might even decrease below 30 to 60 percent," said Bobba. "I mean there's a range there, but bottom line immunity does go down."
Dr. Mike Wasserman who served on California's Vaccine Advisory Committee says educating people -- especially seniors -- on waning immunity and the value of boosters is crucial for us to move forward.
"If we don't spend the time to educate... we're going to be going down the same path," said Wasserman. "People just aren't going to naturally do it. We cannot assume."
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Health officials warn time is running out to get the shot ahead of the holidays where there will be heightened risk for exposure - especially for groups who are immunocompromised or have underlying medical conditions.
"What I would encourage everybody to do is to look at Thanksgiving, go back two weeks and say that's your deadline for getting a booster," said UCSF epidemiologist, Dr. George Rutherford. "Just get it done."
Here is a full list of vaccination sites open across San Francisco, click here to make an appointment.