The CDC cited two studies that showed the effectiveness of the COVID-19 vaccine dropped from 91% to 66%, due to immunity waning over time and the delta variant continuing to be highly contagious.
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"I am not surprised by this new data," said Dr. Monica Gandhi with UCSF.
"It has come down some, but it is still high. We all got our vaccines sometime ago, so that means that our antibodies that are our first line of defense are coming down, but our T-cells are still staying intact protecting us," she explained.
One study was done on frontline healthcare workers, who were first to get vaccinated at the end of 2020. The other study was done on people in Los Angeles County.
It showed breakthrough cases from fully vaccinated people, but a very low number of those were hospitalized.
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The CDC studies showed that just 3% of people fully vaccinated were hospitalized, which doctors in the Bay Area say is a sign of a good vaccine.
"The numbers from the vaccine are still remarkable," said Dr. Stan Deresinski, and infectious disease expert with Stanford Health. "There is no vaccine that is going to completely sterilize a virus, but what is important is limiting the amount of people who can get seriously ill."
They both hope that, despite the new study, people still get vaccinated.
"It is the best thing you can still do to protect yourself and those around you," Dr. Gandhi said. "The more people who get vaccinated can help prevent more people from dying."
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