A new Cleveland Clinic study conducted in the US on influenza vaccines has attracted the attention of vaccine skeptics and prompted questions and concerns about vaccine safety.
“If you get a shot of flu, you’re more likely to get the flu!” Read the April 7th X post, referring to the Prelint study published on April 4th.
breaking: Getting a flu shot gives you a 27% higher chance of catching the flu!!!!
Like the covid jab and most other “vaccines,” flu shots appear to be a terrible breakdown. In a preprint study at Cleveland Clinic, 27% of employees were shot with the flu…pic.twitter.com/w70bvf3wa3
– Tom Renz (@renztom) April 7, 2025
The next day, we must bring news of another X-Post research, “all flu vaccines” from the market with large-scale prospective research on safety and efficacy. ”
The warning cites an unpeer-reviewed article by Cleveland Clinic researchers entitled “Efficacy of the flu vaccine during the 2024-2025 respiratory virus season. Posted on Preprint Server MedRxiv on April 4th. This is disclosed in the bold typeface that says, “It should not be used to guide clinical practice as it reports new medical research that has not yet been evaluated.”
What research says – and what it doesn’t
The study included 53,402 employees at Cleveland Clinic Health System in Ohio, and found vaccinated participants had a higher incidence of infection during the recent flu season. However, a spokesperson for the Cleveland clinic said using the study to draw broader conclusions about vaccines and susceptibility to infections is misleading.
“The data came from a relatively healthy population of about 50,000 healthcare workers and did not represent the general population,” said Andrea Passetti, a spokesman for the Cleveland Clinic.
The flu vaccine helps prevent influenza cases from becoming more serious and hospitalization required. Each year, the U.S. Food and Drug Administration (FDA) Vaccines and Related Biological Products Advisory Committee determines which virus to use for the influenza vaccines next season. Data collected by the FDA, the World Health Organization, the US Centers for Disease Control and Prevention (CDC) and other partners distributed worldwide. (The committee meeting discussing flu vaccine strains for the 2025-2026 flu season has been cancelled.)
According to the CDC, in a season when flu vaccine strains and circulating flu strains match, the vaccines “have been shown to reduce the risk of having to go to a 40% to 60% doctor with influenza.”
Robert H. Hopkins JR, medical director of the National Infectious Diseases Foundation, said the Cleveland Clinic study did not evaluate the main benefits of getting vaccinated from the flu.
“It should be noted that the effectiveness of influenza vaccines varies from year to year, but even if flu vaccinations do not completely interfere with infection, they can still moderate the illness and prevent serious complications, including hospitalization and death,” Hopkins said.
Hopkins said he disagreed with the social media posts calling for the removal of the flu vaccine from the market “completely.” “The behavior will result in illness and death from the flu,” he said.
Study physician and co-author Navin Schresta said the results increased the risk of influenza among vaccinated participants, but the authors did not conclude that the vaccine increased the risk of infection because they understood that the increased risk of risk “may be from unrecognized factors.”
Schresta also said the study did not suggest that the flu vaccine should be pulled out of the market as it would be more likely to catch the flu. “Overall, the flu vaccine is an important public health tool,” he said.
(Bottom: We have incomplete photo credits – no full photo name)
Who took part in the research?
The study includes a large number of people who have been vaccinated, as Cleveland Clinic requires workers to take the flu vaccine annually or seek medical or religion-based exemptions.
Of the participants, 43,857 were vaccinated during the study period, and 98.7% received the inactivated trivalent influenza vaccine. By the end of the study, 1,079 participants had fallen into the flu. This is approximately 2% of the entire study population.
Pacetti said only 2% of participants who signed up for the flu during the study period were notable. “The population didn’t include children, and there were very few elderly people and immunocompromised individuals,” she said.
The results of this study show the cumulative incidence of influenza, or the number of new cases divided by the total number of people at risk in the study (not vaccinated).
The authors found that influenza vaccines have negative effects, “suggesting that vaccines are not effective in preventing influenza.”
What do these findings mean?
The effectiveness of influenza vaccines may vary from season to season (considering characteristics such as age and health), the CDC says. Their effectiveness also depends on their similarity to the influenza virus circulating in the community, the agency said.
Data from agents showed the effectiveness of seasonal flu vaccines, or how much the vaccines hinder severe illness and hospitalization, changing season-by-season at a 42% efficacy rate during the 2023-2024 season. The researchers found that they reduced the risk of influenza-related outpatient visits and hospitalizations among children, adolescents and adults.
Hopkins said the study did not discuss whether workplaces have masking policies or other restrictions for non-vaccinated employees. He said this “may have a significant impact on the incidence of influenza.” The study said about 10,900 participants were working in clinical nursing.
Passetti and Jeffrey Morris, director of biostatistics at the University of Pennsylvania Perelman School of Medicine, also said the vaccine reduces the risk of death or severe illness primarily.
This article states that the effectiveness of a vaccine for a given year “depends on how similar the strains in the vaccine are to the strains that cause infection that year.”
The authors of this study also say that almost all of their participants use trivalent inactivated influenza vaccines, which could make other influenza vaccines more effective.