Medical assistant Letrice Smith fills syringes during a community COVID-19 vaccination clinic in Menlo Park on April 10, 2021. Photo by Anne Wernikoff, CalMatters
In summary
Most of the 7,553 infections were minor, although 62 people have died. The rate of COVID-19 infections and deaths among unvaccinated people is far higher.
About 7,550 out of more than 19.5 million Californians who were fully vaccinated against COVID-19 have contracted the disease, a minuscule percentage that provides strong evidence of the vaccines’ effectiveness, according to state data.
The breakthrough infections through June 23 amount to 0.039% of vaccinated Californians — or one case out of every 2,583 vaccinated people.
Most of the infections were minor, but 62 vaccinated Californians died from COVID-19, according to California Department of Public Health data.
“The way we should think about these cases is that they’re very rare,” said Dr. George Rutherford, a University of California, San Francisco epidemiologist.
The risks of the disease far outweigh the chance of a breakthrough case: More COVID-19 deaths have been reported in the past four days than the total number of vaccinated people who died from it over the past six months.
On Wednesday, state health officials reported 2,013 new infections among all Californians, including 24 deaths. They did not respond to a request for comment.
Nationally, out of 154 million fully vaccinated Americans, 4,115 people have been hospitalized or died after contracting COVID-19. That’s a rate of 0.0027%. More than three-quarters were 65 or older. Federal officials do not track total breakthrough infections because many involve minor or no symptoms.
In California, health officials matched data from the state’s immunization registry to a registry of confirmed COVID-19 cases to identify breakthrough cases.
There are some caveats to the data. While California’s public health agency reported 584 people were hospitalized after a breakthrough COVID-19 infection, hospitalization status wasn’t available for 46% of the post-vaccination cases. State officials also noted that some of them may have been hospitalized for an unrelated condition and tested positive for COVID-19 after being admitted to the hospital.
The three vaccines authorized in the United States – Pfizer-BioNTech, Moderna, and Johnson & Johnson – are considered highly effective in preventing severe disease and death. They also protect against the coronavirus variants now circulating, including the Delta variant, Rutherford said. Yet a small number of breakthrough infections are to be expected, the CDC says. The agency’s surveillance hasn’t turned up any unusual patterns.
Dr. Eugene Choi, a Los Angeles radiologist, contracted COVID-19 in early June, nearly six months after his first dose of the Pfizer vaccine. Choi detailed his experience on his Instagram account, where the CrossFit enthusiast has nearly 40,000 followers.
He told CalMatters that his symptoms included fever, night sweats, chills and muscle pains.
At first, “I did not think of COVID,” said Choi, who as a physician was vaccinated earlier than many Californians. “I thought … okay, it must be that other flus and colds are coming out of the woodwork.” But as his fever continued, he decided to get a COVID-19 test.
Then his wife, also vaccinated, and their two-year-old son became infected, he said. Their cases were more mild.
“I’ve seen firsthand the devastation COVID causes,” he said.
“My experience should give people reason to go get vaccinated,” he said, recalling how cases at the hospital where he works plunged as more Californians were immunized.
Choi wonders if the vaccine protected him from serious, lingering symptoms that many people have experienced. He said he was miserable for days, but never sick enough to need hospital care. He has since resumed his intense workouts.
“It certainly could have been worse,” he said. “I’m still amazed at what the virus can do.”
Our health care reporting is supported by the California Health Care Foundation and Blue Shield of California Foundation.
Barbara Feder Ostrov, Contributing Writer for CalMatters, has reported on medicine and health policy for more than 15 years. She most recently covered California and national health issues for Kaiser Health... More by Barbara Feder Ostrov
Republish
Breakthrough COVID is rare in California
We love that you want to share our stories with your readers. Hundreds of publications republish our work on a regular basis.
All of the articles at CalMatters are available to republish for free, under the following conditions:
Give prominent credit to our journalists: Credit our authors at the top of the article and any other byline areas of your publication. In the byline, we prefer “By Author Name, CalMatters.” If you’re republishing guest commentary (example) from CalMatters, in the byline, use “By Author Name, Special for CalMatters.”
Credit CalMatters at the top of the story: At the top of the story’s text, include this copy: “This story was originally published by CalMatters. Sign up for their newsletters.” If you are republishing commentary, include this copy instead: “This commentary was originally published by CalMatters. Sign up for their newsletters.” If you’re republishing in print, omit the second sentence on newsletter signups.
Do not edit the article, including the headline,except to reflect relative changes in time, location and editorial style. For example, “yesterday” can be changed to “last week,” and “Alameda County” to “Alameda County, California” or “here.”
If you add reporting that would help localize the article, include this copy in your story: “Additional reporting by [Your Publication]” and let us know at republish@calmatters.org.
If you wish to translate the article, please contact us for approval at republish@calmatters.org.
Photos and illustrations by CalMatters staff or shown as “for CalMatters” may only be republished alongside the stories in which they originally appeared. For any other uses, please contact us for approval at visuals@calmatters.org.
Photos and illustrations from wire services like the Associated Press, Reuters, iStock are not free to republish.
Do not sell our stories, and do not sell ads specifically against our stories. Feel free, however, to publish it on a page surrounded by ads you’ve already sold.
Sharing a CalMatters story on social media? Please mention @CalMatters. We’re on X, Facebook, Instagram, TikTok and BlueSky.
If you’d like to regularly republish our stories, we have some other options available. Contact us at republish@calmatters.org if you’re interested.
Have other questions or special requests? Or do you have a great story to share about the impact of one of our stories on your audience? We’d love to hear from you. Contact us at republish@calmatters.org.
Gift this article
Breakthrough COVID is rare in California - CalMatters
Most of the 7,553 infections were minor, although 62 people have died. The rate of COVID-19 infections and deaths among unvaccinated people is far higher.
CalMatters
California, explained
Barbara Feder Ostrov
Barbara Feder Ostrov, Contributing Writer for CalMatters, has reported on medicine and health policy for more than 15 years. She most recently covered California and national health issues for Kaiser Health News. Previously, she covered the medical beat for the San Jose Mercury News for eight years and edited the website of the Center for Health Journalism at the USC Annenberg School of Journalism. She also worked at The Palm Beach Post and the Miami Herald. Her work has been published in the Washington Post, Los Angeles Times, Boston Globe, Atlantic.com, Salon, Scientific American, PBS NewsHour, NPR, CNN.com, Ms. Magazine and Women's Day among other media outlets. She has won awards from the Society for Women’s Health Research, the California Newspaper Publishers Association and the Florida Press Club. She is based in San Jose, California.