(KRON) — Some doctors say it’s not COVID-19 they are worried about this holiday season, it’s the flu.

According to the CDC, California is in the highest tier for flu activity and many other states are also in the red. Influenza is so high now because of the lack of exposure to it in years past therefore lack of antibodies being built, according to Dr. Monica Gandhi, UCSF.

“One of the flu strains is H3N2 which is quite severe. In fact, it caused a problem in 2009 so the particular strain that we have is also more severe,” said Dr. Gandhi.

She also added one of the reasons we are seeing the flu come back in such a major way is because of the COVID-19 virus. “One is a phenomena called viral interference which is a very well-known phenomenon in infectious disease where COVID basically took up all the space in the room that it interfered with other viruses circulating,” said Dr. Gandhi.

She has three recommendations for preventing the flu and it does not include masking. “I really don’t think people can wear masks when they’re eating and I don’t think they’ve been as effective as we’ve hoped,” said Dr. Gandhi.

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She is suggesting ventilation such as opening windows during gatherings. She added only 42 percent of the United States is vaccinated and that is lower than 2019.

“Right now, frankly people are sick of public health. They’re kind of sick of infectious disease doctors, they’re sick of public health, fair enough. There was a lot of disruption in life and people are mad,” said Dr. Gandhi. She also wants to remind people over the age of 65 that they should be getting a higher dose of the flu vaccine.