"This is not the time to throw up your arms and dance for joy that this is gone," said UCSF's Dr. George Rutherford. "It isn't. It's going to be around for a while."
Over the past two weeks the Bay Area's Delta surge started to plateau, but record travel on Labor Day weekend is raising concern that could change.
RELATED: 'It's been challenging:' Labor Day Weekend puts San Francisco vaccine mandate to the test
"Cases are going up in several counties in the Bay Area right now, it's on the order of a few hundred per week," said Rutherford. "That's a troublesome scenario, especially when we thought we'd be over the hump."
Dr. Rutherford says it usually takes around a week after a big holiday weekend to see the impacts of an incoming surge. Will we see one in the Bay Area?
"I think there is potential for that, hopefully it will be less than what we saw in July," said Stanford Infectious Disease Dr. Anne Liu.
Dr. Liu predicts the Bay Area's post Labor Day surge will be smaller since the CDC implemented stricter guidance for vaccinated people to still remain masked indoors, a recommendation the agency didn't have in place leading up to our Fourth of July surge.
"That has changed now for very good reason," said Liu. "I'm hoping people have been more cautious over the Labor Day holiday."
WATCH: SF vaccine mandate now in effect for indoor bars, restaurants, gyms, more
More than 159,000 people have departed through the San Francisco International Airport over the past four days. SFO tells ABC7 this past Friday was the single busiest travel day since the onset of the pandemic.
"Any situation where people are potentially bringing virus from an area where there is a lot of infections to an area where there are not that many infections is concerning," said Liu.
Experts warn the other concerning factor is the current infection rate. ABC7's data analysis shows there were 426 daily COVID cases reported on July 2. Roughly two months later more than 3,200 COVID cases were reported on Sept. 2.
"There is so much more virus out in the community right now," said Liu. "We have to be really careful."
RELATED: How to show proof of vaccination in San Francisco or anywhere in California
Additionally, the percent of fully vaccinated Californians only increased slightly during that time frame. According to the ABC7 vaccine tracker, 51% of Californians were fully vaccinated on July 4. As of Sept. 6, 58% of Californians have been fully vaccinated.
"If you look at Great Britain and what happened there, they had a COVID peak that came up and dropped down," said Rutherford. "It was almost like a saddle... it went down and back up again."
"Do you think that will happen here?" ABC7's Stephanie Sierra asked.
"There's no way to tell one way or the other...it might," Rutherford said. "It's merely cautionary at this point in time. We need to avoid crowds and keep the distancing."
VACCINE TRACKER: How California is doing, when you can get a coronavirus vaccine
Having trouble loading the tracker above? Click here to open it in a new window.
RELATED STORIES & VIDEOS:
- Map shows everywhere you can get a COVID-19 test in the Bay Area
- Mask mandates are back in Bay Area, so what's the safest one to wear? Here's what doctor says
- Here's everything you need to know about COVID-19 booster shots
- What we know about the delta variant of COVID-19 following new CDC report
- Lambda and delta plus: What to know about other COVID variants detected in US
- How to show proof of vaccination in San Francisco or anywhere in California
- Should vaccinated people get tested if exposed to COVID-19? CDC explains
- Can a breakthrough infection still lead to long haul COVID-19? San Francisco doctor explains
- CA COVID-19 Vaccine Tracker: See your status here
- These CA counties are way ahead in vaccinations
- Data tracker: Coronavirus cases, deaths, hospitalizations in every Bay Area county
- Get the latest updates on California EDD, stimulus checks, unemployment benefits
- Coronavirus origin: Where did COVID-19 come from?
- What is a COVID-19 genetic, antigen and antibody test?
- What does COVID-19 do to your body and why does it spread so easily?
- Coronavirus Timeline: Tracking major moments of COVID-19 pandemic in San Francisco Bay Area