New cases of COVID-19 are popping up in San Francisco and elsewhere in the Bay Area in what is clearly a fourth wave of the pandemic, and everyone is clearly anxious and exhausted.

The latest surge in new cases arrived swiftly over the last two weeks, with the numbers in San Francisco still fairly low in the first days of July. The city was averaging 12.6 new cases per day in the month of June, and that rose to an average of 39 per day in the week after the July Fourth holiday. Now, SF's seven-day average, as of Sunday (with a couple of days of delay in the health department's reporting of numbers), was 147 new cases per day. 218 new infections were tallied in SF on Sunday alone, with 196 the previous day, which compares to days in mid-January when we were in the midst of the winter surge. July 20 also saw 215 new cases.

There has not been a day with over 200 new cases in San Francisco since the first week of February.

The number of hospitalized COVID patients has also risen sharply in SF in the last two weeks, rising from 24 on July 1 to 61 as of Saturday, according to state data.

The SF Department of Public Health has not been reporting how many of the positive tests are happening among the unvaccinated versus the vaccinated — but with the numbers this high and likely being underreported, and with 69% of the city aged 12 and up now vaccinated with both shots, it's likely that there are a number of breakthrough cases among these.

As the Chronicle reports, SF General had eight COVID patients as of Friday, and all were unvaccinated. Three were in intensive care.

In Contra Costa County, where infections are being reported as to whether they are among vaccinated versus unvaccinated residents, as of July 24, the rate of infection among the vaccinated was 3.5 per 100,000 residents, while the rate among the unvaccinated was 36.3 per 100,000. The majority of cases occurring among the vaccinated are mild and some are asymptomatic — and some experts say these cases shouldn't even be counted as "breakthrough" cases.

One model from the Financial Times shows how the percentage of fully vaccinated COVID patients hospitalized rises as the percentage of fully vaccinated people rises in a community. This suggests as many as 40% of all hospitalized cases are among vaccinated people, but public health officials have said recently that the majority of these are happening among people over the age of 80 or people with serious underlying health conditions. In places where vaccination rates are low, the overall number of people hospitalized ends up far higher.

This latest surge in cases driven by the Delta variant is happening nationwide, and the picture is far bleaker in places where vaccination rates are lower. In Florida, for instance, hospitals are again becoming overwhelmed — and as the New York Times, reports, one in five new infections in the U.S. is happening in Florida right now.

The surge is undoubtedly being driven by cases among the unvaccinated, who are then spurring the spread of breakthrough cases — which appear to be easier to catch with the Delta variant, though that is not clear.

"The larger the force of infection that comes from the pandemic in unvaccinated populations, the more breakthrough infections there will be," says Bill Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health, speaking to the New York Times. Hanage, presciently, said back in January that Florida was likely in for a bad summer with COVID, and he was very right.

UCSF's Dr. Bob Wachter tweeted a lengthy thread Sunday about the current surge and the precautions he plans to take. He notes that everything they are seeing at UCSF points to the ongoing efficacy of the vaccines, but now 77% of cases they are seeing through routine testing of many patients are among the vaccinated, the chances of encountering the virus in public are much higher in SF now than a month ago. Based on internal data about asymptomatic cases, Wachter says you now have a 1 in 50 chance of encountering an asymptomatic COVID infection while out in the city, compared to about 1 in 1000 back in June.*

In San Francisco, healthcare and restaurant workers are probably facing the greatest sense of frustration and exhaustion.

"Cases definitely are increasing, and there is a sort of — I would call it a triggering," says SF General emergency physician and UCSF professor Dr. Robert Rodriguez, speaking to the Chronicle. "Is this going to accelerate? Is this going to fade? Or are we just going to continue at this rate, this smoldering rate, indefinitely?"

There is some sign of hope in the chart below, showing that in countries with far lower vaccination rates where Delta fueled surges that began earlier than ours, those surges are already in descent.

But as Stanford infectious disease expert Dr. Yvonne Maldonado tells the Chronicle, "We’re going to have to live with this for a while. And we are reaching the point where people have to just settle into that. We have to get back to some kind of a normal life. We can’t keep living like this. But normal life now may be different."

Related: Bay Area Coronavirus Information — Updated Daily

*This post was updated with Wachter's comments later in the day.