There has been a lot of talk, both amongst friends and in the media, in the last two weeks as panic spreads about the Delta variant, mask guidance, breakthrough cases, and the possibility of yet another lockdown. But infectious disease experts are not the ones sounding alarm bells — and they say if you're vaccinated you really need to calm down.

You may already know someone who has tested positive for COVID after being fully vaccinated, and mostly that is to be expected, experts are saying. It's now clear that July Fourth gatherings were to blame for a sharp rise in new COVID cases in the Bay Area and elsewhere, but so far the important data points are: 1) the vast majority of these new cases are among the unvaccinated; 2) the overwhelmingly vast majority of hospitalizations and just about all the deaths happening are among the unvaccinated; and 3) the number of "breakthrough" cases among the vaccinated are not alarmingly high, and the majority of those cases appear very mild.

Also, as UCSF's ever calming Dr. Monica Gandhi explained to NPR on Wednesday, we may all be thinking about "breakthrough" cases incorrectly. A number of positive tests are being recorded among vaccinated people — especially among athletes and groups of people who are undergoing regular, routine testing — but these test results may be misleading for the overall public health picture.

You might test positive as a result of "dead viral particles in your nose," Gandhi says. "Vaccinated people may get it in their nose, but they're going to kill it — that's actually what the immune system does."

And for this reason and others, the CDC does not even recommend seeking testing if you are vaccinated, asymptomatic, and think you may have been exposed. In the end, these "superficial" cases of COVID may not even be considered cases at all — and it isn't even clear if these cases can transmit the virus to others.

Dr. Paul Offitt of the Vaccine Education Center at Children's Hospital of Philadelphia tells NPR that he doesn't even think mild or asymptomatic cases should be counted when we are talking about "breakthroughs."

"I think we are misusing the term breakthrough," he says. "If someone who is fully vaccinated is subsequently hospitalized or killed by the virus, that's a breakthrough case."

Yes, the Delta variant is more contagious, but experts say there's little evidence so far that it's infecting more vaccinated people than would likely have been infected, statistically speaking, by any of the earlier variants. The Pfizer and Moderna vaccines also both seem to be highly effective at protecting people against getting sick from the Delta variant, but maybe only 80% effective at preventing infection completely.

Gandhi earlier tried to calm this discussion down about the Delta variant in an interview with Slate last month, harkening back to the early panic in the HIV epidemic.

"At the very beginning of the HIV epidemic, everything seemed scary," she said. "Any possible risk of getting HIV seemed scary. So [that] was why the words 'stay away from each other' and 'don’t have sex' [were] used instead of 'actually, oral sex is really safe, and let’s do that' or 'let me show you how to stay safe with other types of sex.' And those lessons were learned later."

"So actually," she continued, "the way that scientists are talking now was how scientists were talking at the beginning of the HIV epidemic. It took some time, and everyone was scared and screaming, just like we are now, at the beginning of the HIV epidemic."

Still, Gandhi agrees that mitigation measures like encouraging more mask-wearing indoors are good for tackling this moment in the pandemic, when we still have many unvaccinated people out there getting and spreading this disease. And bars and restaurants in SF are already starting to make vaccination proof mandatory for entry, as another mitigation measure.

On Thursday, the health officers of Contra Costa, Santa Clara and San Francisco counties issued guidance urging all employers to make vaccinations mandatory for all employees.

As of July 14, there have been 14,365 post-vaccination cases recorded in California, which represents less than 0.07% of the number of vaccinated people in the state.

The New York Times also discussed breakthrough cases today, reporting on a widely talked-about outbreak of cases that came out of Provincetown, Massachusetts, where an estimated 66,000 mostly gay people gathered into crowded spaces over the week of July Fourth. Around San Francisco, an unknown number of people who returned from Provincetown were infected and some anecdotally became sick — but the Provincetown Board of Health has only recorded 256 cases among the vaccinated, with 66 among people who then traveled home out of state (though this seems like a likely undercount). Even if the true number is three times that, it still represents a relatively small number among the tens of thousands of vaccinated people partying in Provincetown that week.

The incident highlights how, in the right conditions, vaccinated people may be spreading the virus among each other, or how just a few unvaccinated people might create a cluster of cases if they're spending time in the same unventilated, crowded indoor spaces with vaccinated people. Also, the viral loads of unvaccinated people infected with the Delta variant are much higher than with previous variants, which could exacerbate the spread under the right conditions.

University of Oklahoma biologist Dr. Elyse Freitas tells the Times that she was shocked to find out that 15 vaccinated people got COVID during her wedding weekend on July 10. She pins the blame on her bachelorette party, which was celebrated at bars in downtown Oklahoma City where vaccination rates are low.

So, some spaces are more risky than others, but the experts seem to agree that nothing weird or unexpected is going on. Then again, things could change — and the Times spoke to some other experts who counter the CDC, and say that yes, you should go get tested if you think you've been exposed even if you're asymptomatic and vaccinated, just to be safe.

At a news briefing on Thursday, in response to a question about breakthrough cases and how the vaccines seem to be faring, Dr. Anthony Fauci replied that we still should only be looking at numbers of serious, severe cases among the vaccinated.

"By no means does that mean that you’re dealing with an unsuccessful vaccine,” he said. “The success of the vaccine is based on the prevention of illness."

Related: Don't Be Surprised If More SF Bars Start Demanding Proof of Vaccination to Enter