When summer began, delta was still just an airline. Coronavirus restrictions had vanished and fully vaccinated folks felt liberated — hopping on planes to visit loved ones, munching popcorn in real movie theaters, peeling masks off with the giddy confidence that looser public health recommendations gave them.

It felt, for a blissful few weeks, that the COVID-19 shots were like armored shields, protecting them.

“We were told these vaccines were like unicorn farts,” said Andrew Noymer, an epidemiologist and demographer at UCI Irvine. “The CDC missed another opportunity to be realistic in its messaging. They’re not exactly magic.”

Fully vaccinated Steve Edwards of Big Bear discovered that in July, when he developed what he thought was a head cold. As did fully vaccinated C.P. Smith of Lake Forest, whose general malaise devolved into a wave of fatigue unlike anything he’d ever experienced. It was a summer epiphany for Kristen Howerton of Costa Mesa, whose two fully vaccinated sons tested positive in July and August without displaying a single symptom.

There was hope the vaccines might prove to be impenetrable shields, staving off all infection — but experts say they weren’t designed to do that. They were designed to prevent severe disease and death, and they’re doing that spectacularly well, despite the much more contagious delta variant.

“I got a little cold, almost like allergies,” said Edwards, a manager at Stater Bros. in Big Bear. “I probably wouldn’t have even missed work because of it during normal times, but I knew it was going around at work, so I went and got tested.”

The first test was inconclusive; the second was positive. “I barely knew I had it, and I probably wouldn’t have known if it wasn’t going around the store,” he said.

Breakthrough infections climbing

Fully vaccinated people are indeed getting breakthrough COVID-19 cases with increasing frequency, state data show.

As the delta variant surged this summer, more than 100,000 vaccinated Californians got hit with breakthrough COVID-19 cases over June, July and August — with more than 10,000 cases reported in the last week of August alone.

• On June 2, there were 17.5 million fully vaccinated people in California and 5,723 breakthrough COVID-19 cases, meaning a tiny 0.032% of those vaccinated had tested positive.
• Eight weeks later, on Aug. 29, there were 22.5 million fully vaccinated people in California and 112,460 breakthrough cases — meaning a still tiny, but slightly larger 0.5% of those vaccinated had tested positive.

With the caveat that hospitalization and death data for breakthrough cases are imprecise (the state’s figures include those who went to the hospital for something besides COVID — a car accident, for example — and tested positive upon arrival, and also fail to differentiate between those who died with COVID — such as the car accident victim — from those who died from COVID), the increases were still striking:

• As of June 2, 418 fully vaccinated people had been hospitalized with COVID-19, and 47 had died.

• Eight weeks later, on Aug. 29, 2,944 fully vaccinated people had been hospitalized with COVID-19, and 306  had died.

That’s just 0.5% of California’s total COVID-19 deaths, which now total more than 66,000.

‘One day of fatigue’

“I feel very strongly the Moderna coursing through my system — almost like an internal battle of good and evil,” said Smith, a retired editor for the Orange County Register.

After jaunts to Catalina and Albuquerque, he woke up on a July morning with profound fatigue. His sense of smell had “blinked off” like a light. But within 36 hours, his sense of smell blinked back on — “Hey!” he exclaimed as he entered his kitchen, “I can smell peanut butter!” — and he felt much, much better.

“I never had fever, never had chills, never lost any sense of taste,” Smith said. “I fit into the senior category, a crotchety old 67, but not once did I feel that any breath I took was in any way challenged. Except for that one day of fatigue and the smell blinking off and blinking on, I felt like myself, and I came out thinking, ‘Science worked.’ I really feel that’s what made me safe.”

Dr. Julie Parsonnet, professor of medicine, epidemiology and population health at Stanford University, is sure of that as well. It’s true that, as the number of unvaccinated people drops and the number of vaccinated people rises, we’ll see more cases in the vaccinated — that’s just a function of statistics, she said.

“Overall, the vaccines look great in terms of preventing severe illness,” Parsonnet said. “They’re just incredible. People can be sick — sometimes it’s not just a little runny nose, but more like a bad cold — but then their symptoms go away a lot faster than if they were unvaccinated, and they don’t progress.

“The key thing is, these vaccines are miraculous,” she said. “Miraculous. We’re tuned in to all the negative things, but the fact is, people are going to restaurants, to movies, doing other things — maybe with masks — but getting back to their regular lives. People should be very happy with the vaccines.”

Vaccinated doctors get COVID, too

It may be cruel irony when a fully vaccinated doctor who specializes in infectious diseases gets COVID-19. But that’s what happened to Dr. Paul Adamson, a physician at UCLA Health and a clinical instructor at the David Geffen School of Medicine at UCLA, about six weeks ago.

Adamson was readying for a trip to Northern California — for a baby shower — when he noticed that he had a runny nose. It felt like allergies. But it would be bad to expose people at a baby shower, so he took one of those rapid antigen tests. It came back positive, and was soon confirmed by the gold standard PCR test at UCLA.

He canceled the trip. The next morning, he awoke with deep muscle aches and deep exhaustion. He felt awful — but by later that afternoon, he felt much better, and the next day, felt back to normal.

“It was quite incredible,” he said. “I had aches and pains and a little bit of chills, but it was amazing how quickly I recovered. It lasted about 36 hours, and I felt bad for maybe 18 of them.”

It wasn’t completely over, though: When his wife made his favorite Indian dish, it tasted like a bowl of hot mush. He had lost his sense of taste. But that reappeared about 12 days later.

‘Incredibly stressful time’

Howerton, psychotherapist and author of “Rage Against the Minivan,” never got a breakthrough infection herself, but her two fully vaccinated sons did. Kembe, 14, was exposed at church camp, where some 20 people — most of them unvaccinated — were infected.

“It was real clear that the kids who had been vaccinated had no symptoms, and the kids who weren’t vaccinated, some of them got very sick,” Howerton said. “It’s great that both of my boys had no symptoms, but it was an incredibly stressful time and they both missed big portions of their lives.”

There was worry. What if they had exposed kids on the football team? What if they exposed their sister, who had been rehearsing a play for months?

“That’s the part people may not understand,” Howerton said. “People who feel that vaccination is a personal decision — it’s not. That decision has far-reaching consequences that can affect entire communities, including kids who have vulnerable family members.”

The fallout could be teen disappointments, or days of missed work, or hospitalization, or even death. “Get the vaccine,” Howerton said.

Annual booster?

Philip L. Felgner and his colleagues at UCI’s Vaccine Research and Development Center are studying the strength of immunity over time in vaccinated health care workers at the UCI Medical Center. After six months, they’ve found that the immune response appears durable, declining by only about 10% from the peak.

“Based on our data, it looks like an annual boost — similar to what we expect to get for the flu vaccine — may be recommended,” said Felgner, director of the center. “Since this coronavirus is prone to variants, the annual boost may contain a different variant from year to year, similar to the flu shot.”

COVID-19 continues to mutate, as all viruses do, in populations that are not well protected by vaccination, said Dr. Elizabeth Hudson, regional chief of infectious diseases for Kaiser Permanente.

“Until we get to a time where the virus doesn’t have large numbers of people it can infect, we can expect it to continue to change,” Hudson said. “Some of these changes could be helpful to the virus, and some of them will not be so. At this time, the vaccines we have do provide good protection against all the variants of concern, including delta and alpha, so there’s no need for a different type of vaccine at this time.

“If more changes come to the COVID virus,” she said, “newer vaccines with different types of protection may be needed. When and if that time comes, the mRNA vaccine technology will allow for a rapid scale-up of new COVID vaccines.”

Noymer, the epidemiologist at UCI, is a bit less sanguine.

“Breakthrough cases don’t please me too much,” he said. “Obviously, a symptomatic breakthrough case that, in the absence of the vaccine, could have been a hospitalization or worse — yeah, give me more of that. If it’s a vaccine that converts fatalities into people simply feeling sick, OK. Good. But we were hoping for fewer breakthrough cases at all.

“It’s not that we can’t all survive a few days of feeling crappy. You could spread it to someone else in the period before you became symptomatic. Herd immunity is going to be very elusive if vaccinated people can spread it and get infected, so it’s just going to prolong this whole thing.”

On July 1, Noymer was feeling liberated, finally venturing to restaurants and taking off his mask. By Aug. 1, he was canceling lunch plans and masking up again. “And here we are on Sept. 1,” he said. “I’m nervous, with school starting and breakthrough cases happening. COVID has capacity to surprise us. I know for sure we’ll have at least one other wave before this is all over.”

Adamson, the UCLA doctor who had a breakthrough infection, said Los Angeles hospitals are seeing many COVID patients again, and 99% of them are unvaccinated. “For people who are unvaccinated,” he said, “it’s really quite a threat.”