Omicron is everywhere, and a local infectious disease expert is advising all of us to assume we have COVID if we have had a known exposure, or been anywhere in public really — and especially if we have any of an array of symptoms.

Six COVID testing sites in San Francisco that were forced to close Monday due to a computer issue have reopened, and most of these sites are once again taking walkups. Color, the vendor that runs the sites for the city, announced late Tuesday night that the company's technical issues had been resolved, and the sites at 7th and Brannan, Alemany Farmers Market, Southeast Health Center, Ella Hill Hutch Community Center, 20 Norton Street, and the Bayview Opera House would reopen on Wednesday.

Appointments at these sites that were previously scheduled for Monday and Tuesday have been rescheduled — but as many have found, walking up is just about as efficient, since those with appointments have to wait in line anyway.

There's also walk-up testing available at Glide in the Tenderloin, and at SF General in Potrero Hill. See all available testing sites here.

And if you don't have time to wait in line, or you get turned away, or you can't find an at-home antigen test — there aren't a lot out there — you may need to hunker down and isolate anyway.

That's the advice of UCSF Infectious Disease Specialist Dr. Peter Chin-Hong, who spoke Tuesday to KRON4 about the current testing crisis in the Bay Area.

If you're feeling sick — and that includes anything from sniffles and sore throat, to body aches, fatigue, diarrhea, fever, cough, and more — you probably have COVID. That's just where we're at.

"At this moment you have to assume it’s COVID," says Dr. Chin-Hong. "It could be other things, but because you cant get a test, you don’t know for sure. And you potentially can transmit it to other people."

And if you're having symptoms, assume that you are very contagious.

"Wall yourself off in a cocoon," Dr. Chin-Hong says. "After Day 5, if symptoms are improving you can go out into world with a mask on for additional five days. If symptoms are not improving, you should stay in until symptoms are improving."

The rules for if you've had a known exposure are similar, but a bit more lenient if you've been boosted, he says, or you're asymptomatic.

"If you are not boosted, you stay at home for five days isolating, walling off from society," Dr. Chin-Hong says. "And at Day 5, you can go around wearing mask for remaining 5 days. If you’re boosted don’t have to wall yourself off from society, you can start moving around, but you must wear a mask for ten days."

At-home tests, if you can find one, are still an accurate indicator of infection especially when the infection is peaking. UCSF just put out a paper about a study of 700 patients at an SF testing site last week. All the patients were swabbed twice, and they were tested via both the BinaxNOW antigen test and a PCR test. The BinaxNOW rapid test picked up 95% of cases where viral loads were high — but only 65% of cases where viral loads were low, which likely meant the person was too recently exposed, or they were already recovering from the infection.

Related: Suspicious, Unpermitted COVID-19 Testing Sites Pop Up in SF, Draw Legal Scrutiny

Top image: The line last weekend outside the testing site at First Baptist Church in the Western Addition. Photo: SFist