People who are “up to date” with their COVID-19 vaccinations are more likely to get infected, according to a new study.
Vaccinated people who received one of the updated bivalent vaccines had a higher risk of becoming infected when compared to people who hadn’t—a group that included both vaccinated and unvaccinated people—researchers with the Cleveland Clinic in Ohio found.
The higher risk held even after adjusting for factors such as age and job location.
“This study highlights the challenges of counting on protection from a vaccine when the effectiveness of the vaccine decreases over time as new variants emerge that are antigenically very different from those used to develop the vaccine,” Dr. Nabin Shrestha and other researchers said.
The Omicron XBB subvariant became dominant in the United States in January. The bivalent vaccines from Moderna and Pfizer target BA.4 and BA.5, as well as the old Wuhan strain.
The study, published on the medRxiv server (
pdf) on June 12 ahead of peer review, included 48,344 employees of the Cleveland Clinic, 47 percent of whom had evidence of prior infection. Employees were included if they were employed in the fall of 2022, when the bivalent vaccines first became available, and were still employed when the XBB strain and its lineages became dominant. The study covered Jan. 29 to May 10. People whose age and sex weren’t available were excluded.
Analyzing the vaccine effectiveness with a Simon–Makuch
hazard plot, the researchers treated each employee as “not up to date.” When a worker received a bivalent dose, they started counting as “up to date.” Employees stopped being counted if they were fired.
During the study period, 1,475, or 3 percent of clinic employees, became infected.
Being “not up to date” was associated with a lower risk of infection, with an unadjusted hazard ratio of 0.78 and an adjusted hazard ratio of 0.77. A hazard ratio of less than 1 means a smaller risk of infection.
Researchers didn’t provide vaccine effectiveness estimates because they didn’t calculate how many of the infected employees were unvaccinated, Shrestha told The Epoch Times via email. Most employees, 87 percent, had received at least one dose of a vaccine.
The Cleveland Clinic has been offering employees tests and vaccinations throughout the COVID-19 pandemic. The health care nonprofit started offering bivalent vaccine doses on Sept. 12, 2022, shortly after it was cleared by regulators and recommended for virtually all vaccinated people by the U.S. Centers for Disease Control and Prevention (CDC).
‘Up to Date’
The CDC has defined “up to date” as receiving all recommended vaccine doses. The definition has changed multiple times during the pandemic. It was a primary series at first. Later, a monovalent booster was added.As
of April, being “up to date” for people aged 5 and older
means having had one bivalent dose. For children aged six months to 4 years, it means two doses of Moderna’s or three doses of Pfizer’s vaccine. The latest update was made as authorities replaced the old vaccines with the bivalents, which had previously only been available as boosters.
The Cleveland Clinic researchers wanted to see whether people who meet the current definition of “up to date” were better protected than those who don’t, given the lack of data for the bivalent vaccines, which were cleared
without clinical trial data and to this day lack clinical trial efficacy estimates. The researchers
previously found that the more doses a person receives, the more likely they are to get infected.
The finding that being “up to date” didn’t equal better protection stems from the bivalent not being effective against the XBB lineages, the researchers said. The other reason, they said, is because the CDC doesn’t formally recognize in its vaccination guidance the protection bestowed from prior infection, known as natural immunity.
A key point is that some people who weren’t up to date became infected with the Omicron subvariants BA.4, BA.5, or BQ, which helped provide them better protection against XBB, the researchers said.
“It is now well-known that SARS-CoV-2 infection provides more robust protection than vaccination,” they said, pointing to
three studies, including
one of their own. “Therefore it is not surprising that not being ‘up-to-date’ according to the CDC definition was associated with a higher risk of prior BA.4/BA.5 or BQ lineage infection, and therefore a lower risk of COVID-19, than being ‘up-to-date’, while the XBB lineages were dominant.”
Strengths of the study include its large sample size and ability to examine the data in different ways, such as by date from vaccination and date from a positive test. Limitations included not being able to separate asymptomatic infections from symptomatic infections and, due to a low number of severe illnesses among the study population, the inability of assessing protection against severe illness.
Reactions
Dr. Jeffrey Klausner, a former CDC health officer who’s now a professor of public health sciences at the University of Southern California’s Keck School of Medicine, told The Epoch Times in an email that the limitations mean that the study “does not tell us much at all.”“These types of observational studies cannot adequately adjust for factors that cannot be measured. That’s why randomized controlled trials are the only way to make definitive conclusions,” he said, also predicting that the study wouldn’t pass peer review.
The authors have submitted the paper to a journal, Shrestha said.
Other experts said the findings indicate that the bivalent vaccines don’t protect against XBB.
“The article needs full peer review obviously but does suggest the bivalent COVID-19 vaccination does not offer protection against current circulating COVID-19 infection,” Dennis McGonagle, a clinical professor at the University of Leeds School of Medicine, told The Epoch Times via email. “The high rate of natural infection previously in this large cohort and natural upper respiratory tract immunity, that current vaccines cannot provide, and the likely limited effectiveness of the vaccine to new viral mutants likely has contributed to these findings.”
The CDC didn’t respond to an inquiry regarding whether the study would prompt officials to consider updating its “up to date” definition and why the agency has never recommended people with prior infection get fewer vaccine doses.
“If you recently had COVID-19, you still need to stay up to date with your vaccines,” its
website reads.
Top U.S. officials, including the CDC’s director,
met in late 2021 to discuss the matter and opted against changing the recommended schedule, despite several outside advisers saying they should. Multiple
CDC studies have found that protection from prior infection is superior to vaccination.
The CDC claims that the currently available COVID-19 vaccines “are effective at protecting people from getting seriously ill, being hospitalized, and dying.” Observational studies from the CDC and other entities have estimated that bivalent vaccines provide protection against hospitalization during the BA.4/BA.5 era, but that the protection
quickly wanes.
Early data from the XBB era, presented this week by the CDC,
show effectiveness against hospitalization turning negative after just 90 days. The Cleveland Clinic group’s previous paper found negative effectiveness against infection over time. Protection against infection from similar bivalents used in some countries was just 25 percent during a time period mostly covering XBB, Qatari researchers recently
reported. They couldn’t calculate effectiveness against severe disease because none of the infected cases progressed to that stage.
“It is often stated that the primary purpose of vaccination is to prevent severe COVID-19 and death,” the Cleveland Clinic researchers said. “We certainly agree with this, but it should be pointed out that there is not a single study that has shown that the COVID-19 bivalent vaccine protects against severe disease or death caused by the XBB lineages of the Omicron variant.
“People may still choose to get the vaccine, but an assumption that the vaccine protects against severe disease and death is not reason enough to unconditionally push a vaccine of questionable effectiveness to all adults.”
Natural Immunity
The researchers also looked at how protective natural immunity was. They found that the protective effect was higher for people who were infected by a recent Omicron subvariant when compared to people who were infected by an early subvariant or pre-Omicron strains.The researchers didn’t provide protection estimates for natural immunity against severe disease.
The Qatari researchers previously
found that natural immunity from pre-Omicron strains didn’t protect well against reinfection from Omicron. They were also unable to estimate protection against severe illness, although they
found in a separate study that natural immunity remained strongly protective against severe illness after 14 months.
