MARIN COUNTY (CBS SF) – Marin County health officials said while over 9 in 10 eligible residents have at least one COVID-19 vaccine dose, cases of the more contagious Delta variant are growing among the unvaccinated.

According to the county website, the 7-day average of new cases reached 9.14 as of Friday, exactly a month after the 7-day average dipped to 2.43, the lowest number of new cases since the start of the year.

Officials said since June 1, 12 people have been hospitalized in Marin County with COVID-19, with all but one being unvaccinated.

Health officials said among cases sent for genomic sequencing for variants, the Delta Variant constitutes about 70% of recent cases in Marin County. The health department said it has also detected the so-called “Delta Plus” strain, which could be more infectious than the original Delta variant.

The county has launched a dashboard on their COVID-19 website tracking the activity of variants in the county.

“Sharing this information helps people see for themselves – being unvaccinated puts you at real risk for infection and more severe disease,” said Marin Public Health Officer Dr. Matt Willis. “It’s important to know that the vaccines are effective against the variants were seeing.”

As of Monday, nearly 92% of residents 12 and older have received at least one dose of COVID-19 vaccine, and 84.6% are fully vaccinated. By age group, seniors are the most vaccinated group in the county, with 98% receiving at least one shot.