COVID hospitalizations in the Bay Area ticked above the 500 mark for the first time since early March on Thursday, and daily new case counts continue to be high in San Francisco and elsewhere around the region amid the BA.2 surge. This has led health officials to issue a new stern recommendation about masking that stops short of being a new mandate.

On Thursday, SFist reported on the increasing alarm bells coming from infectious disease specialists and public health figures in the Bay Area about the number of reinfections they've been seeking with the Omicron subvariant known as BA.2 — and its sublineages like BA.2.12.1 and BA.2.13. Evidence of the growing presence of these variants has been seen in wastewater surveillance in the Bay Area, and doctors report seeing patients becoming infected who were previously infected with Omicron BA.1 — meaning that these new subvariants are particularly good at evading any of the body's existing immunity, either from previous infection or vaccines.

The trajectory and length of the current surge remains unknown — and talk of a new "fifth" wave of the pandemic being underway goes back over three weeks. At that time, San Francisco had a seven-day average of daily new cases of 131, and as of this week, that has risen almost threefold, to 343. Several days last week saw recorded case numbers of over 400 in SF — and we know this is a significant undercount because of the wide availability of at-home tests, and younger people with mild cases likely aren't seeking out PCR tests for confirmation.

Chart via the SF Dept. of Public Health

It's unlikely to dampen any of the Bay to Breakers revelry on Sunday, but the Bay Area's coalition of health officers put out a statement Friday urging everyone to mask up indoors whenever possible — with an N95 or KN95! — to keep COVID tests handy, and to isolate themselves at the first sign of symptoms as this wave shows no sign of cresting yet.

"With COVID-19 cases going up in San Francisco, people are at an elevated risk of contracting COVID-19 right now and we are urging people to take personal protections against the virus,” said SF Health Officer Dr. Susan Philip in a statement. "Wearing a mask in indoor, public settings is a smart move, as is staying up to date on vaccinations and, importantly, having a plan to reach a doctor if you get infected. People who are at high risk of severe illness, or who are in close contact with someone at high risk should be especially vigilant as we get through this current swell in cases."

The health officers note that "hospitalizations are increasing but remain relatively low compared to previous surges," and this is thanks to widespread vaccination and at-least-partial immunity among the local population.

COVID deaths remain low both in California and across the country compared to a month or two ago, however this may change as death counts tend to lag about six weeks behind waves of infection.

Also, the test-positivity rate in San Francisco is now significantly higher than in last summer's Delta wave, and could be on its way to hitting a peak like we saw in January, when it hit 18.9%. Experts said two weeks ago that the city's test-positivity rate was "too high" when it hit 5%, and as of this week the positivity rate hit a seven-day average of 9% — having hit 14.5% on Saturday, May 7. This could be due in part to the high preponderance of people getting PCR tests as confirmation when they've already tested positive at home.

Chart via SF Dept. of Public Health

So, if you are so much as slightly congested, you ought to be testing yourself right now before and after being in large gatherings!

Many people have reported very mild symptoms with the recent variants, after being vaccinated and boosted, and the onset of COVID can just feel like bad allergies.

Be vigilant! Don't contribute to the spread!

(Someday SFist would love to stop writing about this.)

Previously: Bay Area Scientists Sound the Alarm That Omicron Subvariants Are Reinfecting People Like Mad

Photo: Getty Images