Pfizer buries data showing mRNA flu vaccine bombed in trial with elderly, not much better under 65

Two years ago, Pfizer anticipated that sales of its rebound-prone COVID-19 oral antiviral Paxlovid and fully approved mRNA COVID vaccine Comirnaty would plummet, but good news appeared on the horizon: The drugmaker's mRNA flu vaccine did well in phase 3 trials in ages 18-64, and Pfizer expected to release results from the 65-and-up cohort "later this year."

The results are finally in: Compared to a standard flu shot, the mRNA vaccine was associated with six times as many adverse events as infections prevented in adults under 65, and it outright failed in elderly people, associated with more deaths and both minor and serious injuries, from injection-site swelling to kidney problems.

The company buried the long-delayed elderly results on the government's clinical trials website this spring, more than a year late and without announcing them to the public or investors, and gave an optimistic take on the under-65 results in the New England Journal of Medicine last week, while admitting the mRNA shot was "associated with more reactogenicity events."

Australian and American drug industry journalists dug into the two arms of the trial, predicting mRNA jabs for flu would face an uphill climb with Trump administration regulators, who have already canceled nearly $500 million in federal projects and contracts that went toward mRNA vaccine development.

Pfizer used the same testing structure for mRNA flu shots as for its COVID shots and still found only an absolute difference of 0.32% for under-65s, requiring vaccination by 300 people to "prevent a single mild, self-limiting illness," physician-turned-investigative journalist Maryanne Demasi wrote in an X thread summarizing her deep-dive review.

"Put simply, it's a manufacturer-funded trial, written largely by Pfizer employees & finds its best efficacy in the endpoint that requires all samples to be shipped to a Pfizer-run central lab for adjudication," Demasi said.

She noted Food and Drug Administration Commissioner Marty Makary and Center for Biologics Evaluation and Research Director Vinay Prasad conditioned future COVID jab approvals on "randomised trials using a saline placebo and measuring real clinical outcomes," a far cry from the Pfizer flu trials.

The elderly findings were so bad "Pfizer decided to break its 2023 promise to investors to disclose them and simply stick them in the virtual filing cabinet that is clinicaltrials.gov," former New York Times reporter Alex Berenson wrote. 

Curiously, Pfizer's "pipeline" page describes its flu vaccine trial as in Phase 2, so it "seems to be pretending it did not" complete the final Phase 3 as described on the ClinicalTrials.gov page, Berenson said.

Another X user noted Pfizer eliminated the age-combined "primary outcome measure" in July 2023, excluding the elderly, and also excluded from the study any participant who had received a COVID vaccine within the past two weeks, which contrasts with the "coadministration" the Centers for Disease Control and Prevention calls "common clinical practice."

Pfizer did not answer queries from Just the News about the elderly findings and its rosy portrayal of the findings for under-65s. Neither did the office of Sen. Bill Cassidy, R-La., the Senate health committee chairman, who has sparred with Health and Human Services Secretary Robert F. Kennedy Jr. on research that could undermine vaccine confidence.

Conventional flu vaccines were already losing credibility in recent years, with just 16% effectiveness in the 2021-2022 flu season and some evidence they may increase the risk of flu infection, such as the Cleveland Clinic's study of its own employees this spring.

The most recent estimates from the CDC, for the 2023-2024 flu season, say 55% of children got a flu vaccine, down more than eight percentage points from the "pre-pandemic 2019–20 season." It was 45% for adults, their lowest since 2017-2018 (37%).

The results for the roughly 27,000-elderly arm show 49 deaths among those who received the mRNA shot compared to 46 who received the standard jab; 22 with serious kidney problems – "acute" injury, chronic disease or "end-stage renal disease" – compared to 9; and 17 with "acute respiratory failure" compared to six. 

Nearly three times as many people in the mRNA group (69%) reported "local reactions" at the injection site within a week, including "redness, swelling and pain," and nearly twice as many (59%) reported "systemic events" such as vomiting, diarrhea, chills, new or worsened muscle pain and joint pain.

The mRNA group was also about 6% more likely to get infected, a recurring problem with mRNA vaccines in general, especially with booster doses. Recently published research in a prestigious British medical journal found that COVID-vaccinated young people who got reinfected faced higher risks of some serious conditions, including acute kidney injury.

The NEJM study of the 18-64s, with several thousand fewer participants than the 65-and-up cohort, found relative efficacy of the mRNA jab compared to the standard jab to be 34.5%, with a wide confidence interval, meeting the criteria "for both noninferiority and superiority."

It also noted higher rates of mild to moderate adverse events in the mRNA group but less stark, largely due to the standard shot recipients under 65 having more frequent AEs than did the standard recipients over age 65.

Berenson emphasized the mRNA shots were associated with 174 more adverse events related to "system organ class" than the standard jabs in the under-65 adults, more than twice as many, with an especially wide gap between the two flu shots on post-vaccination blood and lymphatic system disorders – 26 versus 2.

Even the smaller gaps between the non-elderly adults are alarming, Demasi said. "For every 1 mild flu-like illness the mRNA vaccine prevents, it causes >50 others to experience systemic flu-like symptoms," she wrote.