COLUMBIA, S.C. (AP) — COVID-19 has closed a South Carolina high school and forced a sheriff's candidate to spend the final week of her campaign in isolation as the spread of the virus has not been slowed in the state.

Lancaster High School had five staff members test positive for the coronavirus and 30 others in quarantine, the Lancaster County School District said in a statement Wednesday.

There aren't enough employees and teachers available to keep students safe, so all in-person classes and activities are cancelled until Nov. 9, officials said.

The school had split students who wanted to be at class at the school into two groups with each group coming twice a week.

COVID-19 also disrupted the campaign for Charleston County sheriff. Democratic challenger Kristin Graziano disclosed Tuesday that she tested positive for the virus and was going to run her campaign in isolation at home until she tests negative again.

Graziano is challenging Republican Sheriff Al Cannon, who is running for a ninth four-year term.

Graziano is trying to become the first woman elected sheriff in South Carolina's history. She said she was exposed to COVID-19 while working a part-time job she had to take because Cannon placed her on unpaid leave from her job on the Charleston County Sheriff's SWAT team while she ran against him.

Meanwhile, COVID-19 cases across the state continue a slow climb. The seven-day average for new cases is over 1,000 — a mark it hasn't been at consistently since mid-August.

After dipping for more than a month, COVID-19 deaths are on the rise too, averaging more than 20 a day. The virus has killed at least 3,645 people, the South Carolina Department of Health and Environmental Control reported.

The percentage of tests that come back positive in South Carolina continues to hover about 10%, which is the rate above which health experts say the coronavirus is either continuing to spread or not enough testing is being done.

Two upcoming events have health officials worried. First is Halloween, where people are being encouraged not to gather large groups and take precautions like social distancing and masks if they decide to celebrate.

And on Tuesday, experts recommend masks and social distancing for people heading to vote. Election officials are also taking precautions including giving cotton swabs for voters to use on touch screens, Plexiglass barriers between voters and clerks and sending plenty of hand sanitizer and cleaning supplies to polling places.

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Follow AP coverage of the pandemic at https://apnews.com/VirusOutbreak and https://apnews.com/UnderstandingtheOutbreak.