EVERETT — You’re more likely to get COVID-19 from a family member, friend or roommate than anyone else in Snohomish County.

In July, 60% of new COVID-19 patients got the virus from a close contact, as opposed to roughly 30% of patients who became infected through random community transmission, according to a weekly report from the Snohomish Health District.

The rise in cases, which started in June, has largely been driven by expanded social circles and people letting their guard down, said Dr. Chris Spitters, the county’s top health officer.

“What seems benign, or is only a little bigger than the current guidance, still leads to transmission,” he said. “They’re seemingly innocent. They say it doesn’t seem like that big of a number, or, ‘Oh, I trust these people.’ It’s really not about trust. Even if you like and trust them, you just don’t know where they’ve been.”

The county is reporting nearly 100 cases per 100,000 people in the latest two-week period — four times the rate when Snohomish County entered Phase 2 of Gov. Jay Inslee’s Safe Start plan. Nearly 40% of new infections are in people under 30, but cases are starting to creep up with older age groups.

Spreading the virus to someone you live with is the most common form of transmission. Then, it’s small gatherings like barbecues or birthday parties.

To make matters worse, hospitalizations from the virus have also slightly increased.

Spitters said Snohomish County could be experiencing what happened in Florida, where cases spiked among young people, then spread to older groups and led to a jump in hospitalizations and deaths.

“That’s what we obviously don’t want to see,” he said. “Without improvement, I’m concerned this is going to keep rolling.”

To prevent the spread of the virus, wear a mask — even around close contacts — limit your social network to five non-household contacts each week and isolate and seek testing if you experience symptoms like a fever, cough, sore throat or chills.

Keeping your social circle small makes it easier to contract trace and contain the virus if you become infected, Spitters said.

If you’re over 60, avoid younger people when possible.

“The pathway to sustainable enjoyment of life and thriving is through these measures, as painful as they are in the short run,” he said. “It’s like chess. You’ve got to think a couple moves down the road.”

Meanwhile, the health district is still struggling to reach people within 24 hours of a positive test result.

For weeks, tracers have been making contact with just half of new COVID-19 cases in that time span. The benchmark to enter Phase 2 was 90%.

Health experts have long said that effective contact tracing is pivotal in the fight to contain the virus.

People ignoring calls from tracers, staffing issues and delays in testing are all contributing to the slowdown in contact tracing.

Testing delays stem from states like Florida, Arizona and Texas flooding labs with samples. Those delays are now being felt with the health district’s testing, where results now take three to four days, instead of two to three.

At the same time, the response rates mirror previous tracing efforts for other diseases, Spitters said.

He added that although the county’s trending in the wrong direction, masks, testing and contact tracing are helping.

“If you look at the slope of the curve of the current wave, roughly speaking, it’s about half as steep as it was in March,” he said. “One reason could be these imperfect, but community-wide, efforts.”

Joey Thompson: 425-339-3449; jthompson@heraldnet.com. Twitter: @byjoeythompson.