A peer-reviewed preprint study from Cleveland Clinic researchers, released Friday, reveals a 27% higher flu risk among vaccinated working-age adults. The study starkly concludes that this season’s influenza A and B vaccine is linked to increased infection rates, challenging its effectiveness.

Focusing on the 2024-2025 respiratory viral season, the research aimed to assess how well the flu vaccine protects against infection. Instead, the authors found that vaccination “has not been effective in preventing influenza this season,” raising concerns about current immunization strategies.

Modernity.news reports: Employees of Cleveland Clinic who were employed in Ohio as of October 1, 2024, were included.

Cases of influenza among the vaccinated and unvaccinated were compared over the following 25 weeks.

Vaccination protection, treated as a time-dependent covariate, was assessed via Cox regression, meaning its effect was modeled based on the time each individual received the vaccine.

Among 53,402 employees, 43,857 (82.1%) had received the influenza vaccine.

Influenza occurred in 1,079 (2.02%) during the study.

While the cumulative incidence of influenza was similar for the vaccinated and unvaccinated states early, over the course of the study, the “incidence of influenza increased more rapidly among the vaccinated than the unvaccinated,” according to the study.

Significantly, people had a remarkably higher risk of getting the flu after being vaccinated compared to when they were unvaccinated.

The data showed a 27% increase in risk after vaccination, with vaccine effectiveness calculated at –26.9%, meaning the vaccine was associated with worse outcomes in this group.

The risk of influenza “was significantly higher for the vaccinated compared to the unvaccinated state (HR, 1.27; 95% C.I., 1.07 – 1.51; P = 0.007), yielding a calculated vaccine effectiveness of −26.9% (95% C.I., −55.0 to −6.6%),” the study reads.

“Among 53,402 working-aged Cleveland Clinic employees, we were unable to find that the influenza vaccine has been effective in preventing infection during the 2024-2025 respiratory viral season.”

You can Download the full study.

A follow-up report on TrialSiteNews.com confirmed that the study results could not have been due to testing bias because “while vaccinated individuals were more likely to get tested, their test positivity rate was nearly identical to the unvaccinated, indicating a true excess of infections.”

The report also pointed out how vaccinated individuals had a higher risk of flu, with no evidence of protection at any point—raising serious concerns about possible vaccine-related harm, especially given the strong, consistent signal in a healthy, compliant, and relatively young population:

“The findings are deeply concerning. The negative vaccine effectiveness (VE) figure—suggesting harm rather than protection—contradicts public health messaging and raises serious questions about strain mismatch, immune interference, or potential vaccine-related susceptibility. This was not a marginal statistical fluke. The signal held in both unadjusted and adjusted models and was detected early using time-dependent methods. No protective effect emerged at any point.”

“Moreover, this wasn’t a flawed population. The cohort skewed young (mean age 42), mostly healthy, with high occupational compliance. The data were robust enough to reject the common defense that odds ratios from ‘test-negative’ studies exaggerate protection—because here, direct risk was measured.”

It emphasized the need to rethink taking yearly flu shots.

“This hard-hitting real-world analysis suggests the 2024–2025 flu vaccine not only failed to protect working-age adults but may have increased their risk of infection. In an era of mounting skepticism and vaccine fatigue, public health authorities must reckon with data like this—not dismiss it. Annual flu vaccine strategies may need a serious rethink, particularly in years of poor strain matching. At minimum, real-time effectiveness tracking should become a national imperative, not an afterthought.”

In light of these findings, the question is no longer whether annual flu shots should be re-evaluated—but how long public health officials will ignore clear, data-driven signals that this year’s vaccine may have done more harm than good.