Should Californians Worry About Breakthrough Coronavirus?

CALIFORNIA — This summer was supposed to be America’s return to normalcy, but, for many Californians, the haven provided by the coronavirus vaccine is beginning to look like a mirage.

The summer surge fueled by the delta variant took many health experts by surprise. The Centers for Disease Control and Prevention reported last week that the delta variant is as contagious as measles. Half of the Golden State returned to indoor mask mandates within weeks of lifting them. Amid the disconcerting headlines about breakthrough cases, health officials are trying to hammer home the point: The vaccine still offers the best chance of avoiding serious illness and death from COVID-19.

As Californians return to some semblance of life before COVID-19, transmission could be on an unstoppable trajectory.

"You're probably getting to a point where you have two choices — you can either get vaccinated or you can get COVID," said Dr. Timothy Brewer, a professor of infectious disease at the David Geffen School of Medicine at the University of California, Los Angeles. "And if you get the virus, chances are it's going to be much worse for you if you have not been vaccinated."

Breakthrough Cases Rise

The sudden shift back to some coronavirus restrictions has left many vaccinated Californians to wonder whether they're still protected. Scientists and federal health officials are racing to find out how "the war has changed" amid the highly transmissible delta variant.

"It's not surprising that as more people get vaccinated, more infections are occurring in vaccinated individuals, because we know the vaccines aren't 100 percent effective," Brewer told Patch. "And the vaccinated people will count for the majority of the people in the population once you get enough people vaccinated."

In California, breakthrough coronavirus cases increased between July 14 and July 22, from 0.069 percent to 1 percent, state data showed. In Los Angeles, the epicenter of the state's current surge, health officials found that fully vaccinated residents 16 and older made up 20 percent of all confirmed COVID-19 infections in June. In that same month, those cases were only linked to 8 percent of hospitalizations. In July, more than one-quarter of new infections were reported among fully vaccinated Angelenos.

"Although vaccinated people are seeing a rise in new COVID diagnosis, they are primarily experiencing their infections not as severe illnesses that bring them to the emergency room, but as bad colds," Barbara Ferrer, the county's public health director, said in late July.

The breakthrough outbreak that rattled Americans and dominated headlines last week was in the CDC study that showed three-quarters of people infected in a Provincetown, Massachusetts, coronavirus outbreak were vaccinated. The study also found that — thanks to the supercharged delta variant — vaccinated people carried as much virus in their nose as those who were unvaccinated, meaning they could be spreading the virus more than previously thought.

The findings pushed the federal agency to reverse some guidance on mask-wearing for vaccinated people and reissue recommendations for all Americans to wear masks indoors.

Should vaccinated Californians be worried about falling ill? Not necessarily, but they may want to worry about passing the virus to those who are vulnerable.

"Just to remind people, we know that breakthrough cases will happen in vaccinated individuals and fortunately, so far, when they do happen for most people, they seem to be mild," Brewer said.

Return Of The Mask

Having to dig out masks again nearly two months after Californians were told to toss them aside was disappointing for many, to say the least.

"I think the one potential downside of mask mandates is: How does that impact the willingness of people to get vaccinated? If one of the reasons you were going to get vaccinated was you didn't have to wear a mask, and you take that reason away, then mask mandates are not a good thing," Brewer said.

The goal of mass vaccination is to get to a point where coronavirus no longer poses a serious threat to the public. Essentially, if vaccination rates rise, the virus would join the lineup of other pathogens humans are used to, such as influenza and the common cold.

"I think that's a reasonable goal," he said. "I don't think we're going to eradicate SARS-CoV-2 from circulating in the human population."

When the state reopened June 15, public health officials said that transmission was expected to increase. What they didn't yet know was just how transmissible the delta variant was going to be — up to 60 percent more contagious than the version of coronavirus Americans had become familiar with.

The delta variant made up 84 percent of cases sequenced in July — a 31.3 percent increase since June, California health officials said last week.

But the most hair-raising finding was this: The mutation is as contagious as chickenpox and measles, according to a CDC report. That report was already impelling California counties, cities and employers to explore vaccination mandates and proof of testing to enter public areas or workplaces this week.

"So measles is probably the most contagious human pathogen there is, and varicella [chickenpox] is close behind," Brewer said "In order to really hit herd immunity for measles, you have to be consistently at or above 95 percent population vaccination."

In August 2019, a New Zealand teenager infected with measles visited Disneyland. Within that same month, the park experienced an outbreak, and the CDC recorded the largest measles outbreak in the U.S. since 1992, the Washington Post reported. Vaccination rates for measles in 2019 were above 90 percent, Brewer said.

"For something that is that contagious, you really need to be almost at 100 percent," he said. "So if the CDC is correct ... we're looking at trying to hit vaccination rates around 95 percent."

The Case For Vaccination

In California, more than 63 percent of residents have been vaccinated, leaving a large pool of people left in the lurch.

"I think one of the disappointments has been that we had a nice burst of vaccination in the spring, but then things really started to fall off in May, June, July in terms of the number of people willing to be vaccinated," Brewer said. "So I think that was unfortunate that we didn't get the numbers up higher, both within the state and nationally, though we're doing better in California than the country as a whole."

While California's vaccination rates have picked up in recent weeks — by 41 percent — there are still many who are wary of the vaccine.

"I think you just have to realize that the risk of harm from the virus far exceeds the risk of harm from the vaccine," Brewer said.

An unvaccinated average adult with no underlying conditions risks a 15 percent chance of the virus escalating into serious disease, he said. The risk of hospitalization is about 5 percent and the risk of death is around 1 to 2 percent, added Brewer.

"If you survive, your risk of post-COVID syndrome, or what's called long-hauler disease, is somewhere between 30 and 80 percent — that's if you have not been vaccinated," he said.

On the flip side, the risk of anaphylaxis, blood-clotting or Guillain-Barré syndrome "is running in the order of two to 11 per million," Brewer said.

"And a number of these things like blood clots and anaphylaxis are treatable. So it's not even like you're going to die, or have long-term consequences if those happen to you," Brewer said. "So, you know, you're talking about risks that are a thousand times lower of having bad things happen to you."

Between Jan. 1 and July 14, there were 843 people in California infected with COVID-19 who were vaccinated. Fast forward to July 22, and that number has increased to 934 people, showing a dramatic uptick in the rate of breakthrough infections in July. But state officials note that 56 percent of those cases have "missing hospitalization data," meaning that more than half of those people may have been admitted for a condition unrelated to COVID-19, state health officials said.

One argument that has circulated among the vaccine-hesitant has been the idea that antibodies from contracting the virus could also provide protection from future infection. While this is true to a certain extent, Brewer warned against testing that method out.

"It's true that infection will generate an immune response that will protect you from future infections," he said. "But you do that at a much higher risk of having something really bad happen to you, including getting sick enough to be in the hospital or to potentially even die, or have long-term problems like brain fog or recurrent joint aches or fatigue.

"The question is, why do you want to expose yourself to that risk if you don't need to?"