Last month, the county saw its highest number of deaths from the disease in over a year.
"What we're seeing right now, are higher rates than we're seeing last winter," said Marin County's Public Health Officer Dr. Matt Willis.
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He believes the spike is being driven by a number of factors.
Those include more transmissible variants, as well as hotter than normal temperatures in July.
"As summer comes, there's more gatherings. We've had gatherings both indoors and outdoors. As we've had heat waves people were coming indoors in air-conditioned settings. That might have fueled transmission," Dr. Willis said.
The uptick in COVID cases has gotten the attention of more than just the public health department.
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At senior living facilities like The Redwoods in Mill Valley, they tell ABC7 News reporter Tim Johns that they're taking extra precautions to help keep residents safe.
Kyle Ruth-Islas is the chief operating officer at The Redwoods.
He says while they've had a few cases in the community, they've mainly been able to keep things under control.
An accomplishment Ruth-Islas credits to some of the steps the community has taken.
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"Some of the measures that we've kept in place are screening all of the visitors that come to this community to see if they've had any symptoms of COVID-19 or tested positive recently for the virus. We're also practicing universal masking at our skilled nursing facility at this point," Ruth-Islas said.
As for everyone else, Dr. Willis says vaccination remains the most effective tool for protection.
He says while he's heard that vaccines have been harder to come by ahead of an expected new shot in the fall, he's encouraging everyone to get up to date on their vaccine series as soon as possible.
"With the transmission rates as high as they are right now that's too long to wait. So we want people to really reach out to their medical provider and get the vaccine now, especially those that are in that over 65 age group," said Dr. Willis.
Willis's department is also recommending people in that age group mask up at indoor public settings until this surge is over.
For latest on Marin County's summer COVID surge, see stats here.