The U.S. Centers for Disease Control and Prevention has moved Kauai County from the yellow, medium-risk community level to the red, high-risk community level as COVID-19 case counts statewide continue to rise.

Under CDC recommendations, those living in high-risk counties should wear a well-­fitting mask in public places indoors as well as on public transportation, regardless of vaccination status.

Those who are immunocompromised or at high risk for severe illness should consider additional precautions, such as avoiding nonessential indoor activities in public.

Honolulu, Maui and Hawaii counties remain at medium-risk yellow, where they have been since late April after having been slotted in the low-risk green category for weeks. The metrics used to determine community risk levels are based on hospital occupancy rates, new COVID-19 admission rates at hospitals and new coronavirus case rates per 100,000 people.

On Wednesday the state Department of Health reported the weekly average of new cases statewide was 722 per day, representing the seventh consecutive weekly increase.

On Kauai the seven-day average was reported at 48 and the average positivity rate at 20.3% — higher than the state’s average of 14.3% and higher any other county.

Due to its limited hospital capacity, Kauai is prone to reaching red sooner than Honolulu, which has more capacity, DOH Director Dr. Libby Char said Friday during an appearance on the Honolulu Star-Advertiser’s “Spotlight Hawaii” livestream program. “I think it’s a combination of there being a lot of COVID out there in the community, and then Kauai also doesn’t have as much hospital capacity,” she said.

Also, Char maintained that actual coronavirus case counts are likely five to six times higher than reported tallies due to unreported results from home COVID-19 test kits. Statewide, that means there were likely 3,500 to 4,000 new cases a day, rather than the 722 reported Wednesday.

Char said she expects the case counts to continue climbing amid graduation season and as more people gather and travel. To safeguard public health, she said, Hawaii residents know what to do: wear a mask indoors, get vaccinated and boosted, and opt for outdoor events — rather than indoor events — when possible.

She said people now need to make “good decisions” when it comes to large gatherings. “For a while it was OK, but with the numbers being up there, I think I’d avoid large gatherings,” Char said. “If you’re going to have gatherings, please try to do it smartly — do it outdoors, do it in a place that’s well ventilated, where people can spread out.”

Char said she does not think the state needs to impose an indoor mask mandate at this time. Ultimately, she said, that’s a conversation for the governor to have with county mayors.

On Thursday, Kauai County Mayor Derek Kawa­kami noted the isle’s high rates and urged people to wear a mask in crowded spaces and limit their gatherings.

Lauren Guest, Kauai District Health Office deputy director, said more than dozen active COVID-19 clusters are under investigation, mostly at workplaces where there was extended close contact among staff not wearing masks. Many of the workplace clusters started with an employee who went to work while sick, she said.

Several other clusters are related to youth events held outside of schools where masking and distancing were not required.

Char advised anyone who is sick to stay home, even if their home test results initially come back negative. She noted that cases have occurred in which vaccinated people experiencing mild symptoms initially test negative and subsequently test positive.

Also, she warned that a previous COVID-19 infection does not make anyone “bulletproof” from getting reinfected. “We’re seeing reinfection,” Char said. “It has to do with the virus evolving and the variants changing, just from all those mutations. If you had COVID a while back, you’re absolutely susceptible to being infected again.”

Kauai County falls into a small set of communities classified as high-risk. As of Thursday, when the levels were updated, CDC said more than 90% of the U.S. population lives in a location with a low or medium risk level.

“The numbers are trending up right now,” said Char. “We know we have an awful lot of COVID in our community. So, just assume there’s a lot of COVID out there and it’s all around us. That being said, we’re not seeing the same degree of people ending up really sick in the hospital, and I think that’s because we’ve had progress in being able to treat it and also in people being vaccinated and boosted.”

Still, she emphasized the importance of wearing a mask right now.

“Wear your mask, wear your mask, wear your mask, especially if you’re indoors — or even if you’re outdoors, if you’re in a crowded place,” she said. “Get vaccinated. It works. Get boosted. It works. And if you do get COVID, please call your health care provider as soon as you can and see if you’re appropriate for some sort of treatment, because that also works.” Char added, “But really, wear your mask.”