No, a vaccine doesn't make you 'Superman.' Breakthrough COVID-19 cases are increasing amid delta variant.
Staci Martin is doing her grocery shopping online again.
She's fully vaccinated but considers herself and family at renewed risk from COVID-19. She has a chronic condition and an unvaccinated child in the house, and cases around her home in Virginia Beach, Virginia, are skyrocketing.
She's particularly alarmed by studies that suggest vaccinated people can have lingering health problems if they get sick, so she closely watches her state's COVID-19 data dashboard. It shows “breakthrough” cases have been ticking up.
“I’m worried more now,” said Martin, 50. “We’re not going out much."
She's not wrong to worry.
From the earliest days of the pandemic, public health officials told Americans vaccination was the way back to normal life, but the path forward has become less clear. While COVID-19 vaccines were delivered in record time, the promise of vaccine salvation was upended by entrenched hesitancy, waning immunity and a wildly contagious mutation of the enigmatic virus that causes the disease.
Three studies released Wednesday by the Centers for Disease Control and Prevention underscore the new reality: Breakthrough infections are occurring more frequently than previously reported.
“Recent data makes clear that protection against mild and moderate disease has decreased over time,” U.S. Surgeon General Vivek Murthy said during a Wednesday briefing. “This is likely due to both waning immunity and the strength of the widespread delta variant.”
There’s no way to know exactly how common breakthrough infections are across the country, for several reasons. Many cases are asymptomatic or mild enough for people to forgo testing, and the United States doesn't track post-vaccination infections in any organized way.
Americans are flying blind.
“The variability in tracking is all over the place,” said Dr. Eric Topol, vice president for research at Scripps Research in La Jolla, California, and an outspoken writer on COVID-19. "It’s totally chaotic."
Topol said breakthrough infections are a critical statistic for several reasons. In places that do a good job of tracking post-vaccination infections, such as his home county of San Diego, the data present a compelling picture of the vaccines' effectiveness.
Right now in San Diego County, the nation’s fifth-most populous, vaccinated people have a rate of infection about nine times less than the unvaccinated – and a rate of hospitalization that’s 35 times less.
The numbers also can help vaccinated people make informed decisions about their own risk, Topol said.
“Most people think if you’re fully vaccinated, you’re good to go,” he lamented.
As the highly contagious delta variant spreads and cases soar, vaccinated people need to recalibrate the way they live, multiple experts told USA TODAY. That means going back to masking, social distancing and avoiding large crowds.
Delta requires a “layering of protection,” said Dr. Lucy Horton, an infectious disease specialist at the University of California, San Diego. She compared the current COVID-19 vaccines to an umbrella, and called earlier variants of the virus a rainstorm.
Delta, she said, is a "hurricane."
How effective are the COVID vaccines against the delta variant?
The latest CDC studies showed the Pfizer-BioNTech and Moderna mRNA vaccines may not be as effective against the delta variant compared with the original virus, bolstering the Biden administration’s decision to begin COVID-19 booster shots for most Americans this fall.
In one study, researchers found the effectiveness of the vaccines against infections declined from 91.7% to 79.8% between May 3 and July 25 as the delta variant dominated cases in New York.
Another study published by the agency found the two mRNA vaccines were 74.7% effective in nursing home residents nationwide between March and May, but protection dropped to 53.1% between June and July, also as the delta variant picked up momentum.
While it is clear breakthrough infections are increasing, the studies showed hospitalizations remained stable, an indication the vaccines continue to hold up against severe illness.
“When they do get hospitalized, they might need a little bit of oxygen, a couple of days in the hospital, maybe a little IV fluid if they’re dehydrated, and then they go home," said Dr. Amy Edwards, an infectious disease specialist and associate director of infection control at University Hospitals Rainbow Babies and Children’s Hospital in Cleveland.
"You very rarely hear of somebody with breakthrough COVID on a ventilator," she said.
In general, most breakthrough infections are asymptomatic or mild, said Dr. David Boulware, a professor of infectious disease at the University of Minnesota, which partly explains why it’s hard to track such cases.
"Even 'mild' COVID-19 cases can be rather miserable and unpleasant," he said. "Importantly, while unpleasant, they are not generally life-threatening."
How common are breakthrough infections?
The CDC in May stopped tracking breakthrough infections beyond those that result in hospitalization or death. Before that, the agency published a report showing that of approximately 12 million people vaccinated from January through April, 10,262 infections occurred in those fully vaccinated. The findings, however, predate the rise of the delta variant.
“The reason why the CDC dropped breakthrough infections is that they’re really hard to follow in a consistent way,” said Arnold Monto, a professor of epidemiology at the University of Michigan School for Public Health. “You can try to quantify it, but ... precise quantification is going to be very difficult.”
Regular surveillance can produce inaccurate results because asymptomatic infection and transmission are prevalent, he said. Studies could yield more accurate findings, but may be biased, as volunteer participants are naturally more risk-averse, leading to results that aren't nationally representative.
What baffles most health experts is not that breakthrough infections are occurring, but that Americans are so surprised by them. There was an overarching misunderstanding about the COVID-19 vaccines from the beginning, they say.
“People had this superman impression,” said Dr. Aaron Glatt, an infectious disease specialist at Mount Sinai South Nassau in New York. “You can still get COVID-19, but you’re much less likely to, and even if you do, it’s really unlikely to be a severe case.”
The only exceptions seem to be the immunocompromised, those with other existing significant health problems, or the very old. Otherwise, most hospitalizations and deaths are occurring among the unvaccinated.
“Right now, I don’t have a single vaccinated person in my ICU,” said Glatt, a fellow with the Infectious Diseases Society of America.
What kind of vaccine will COVID-19 end up requiring?
Still unknown is what vaccine schedule will be required to protect against COVID-19.
Vaccines tend to fall into two groups. Some consist of a series of two or three shots given over the course of months or years. By the end of the series, they teach the body once and for all how to fight off a given disease. That’s how vaccines for measles, polio and hepatitis B work.
The vaccine for influenza has to be taken every year because the virus mutates enough that new vaccines are always needed to keep up with it.
Getting two doses of an mRNA COVID-19 vaccine three to four weeks apart and then one at eight months is comparable to the schedule for diphtheria, tetanus and whooping cough. But it's not yet clear that new schedule will be the final one needed to fight COVID-19.
“It’s a new virus, so we don’t know. We’re going to have to continue to track and make changes as needed,” said Dr. Walter Orenstein, associate director of the Emory Vaccine Center and the former director of the immunization program at the CDC. “We need to see if vaccine failures increase, and if the reason for the increase is because the virus is mutating or because of waning immunity in the person."
The lack of clarity at this point isn’t surprising, said Orenstein, whose history with vaccines goes back to the successful effort to wipe out smallpox in the 1970s.
“People are frustrated with the changes, but they’re coming because there’s new information," he said. "This is a completely new virus and we had no experience with it until recently. It’s not like we’ve had decades to study it."
Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.
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