SACRAMENTO (CBS13) – Health officials say the flu is reaching levels in California usually seen later in the season.

The California Department of Public Health says flu season started on Sept. 29. Since that date, officials there have been a total 18 flu-related deaths reported in the state.

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Two children are among those who have died.

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Unique to this year, doctors are also cautioning that early flu symptoms and respiratory issues linked with vaping are very similar. People who vape are being strongly urged to get a flu shot as a result.

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Health officials note that it takes a couple weeks for someone’s body to build up immunity after getting a flu shot – so it’s important to get vaccinated as soon as possible.