CLAIM:
Dr Mehmet Oz, administrator of the US Centers for Medicare and Medicaid Services, questioned the effectiveness of seasonal flu vaccines, calling them “controversial” and suggesting that lifestyle measures such as sunlight, supplements, exercise, and sleep can help the body “overwhelm” influenza instead of relying on vaccination.
FACT:
Scientific evidence from the US Centers for Disease Control and Prevention and multiple peer-reviewed studies shows that seasonal flu vaccines consistently reduce the risk of severe illness, hospitalisation, intensive care admission, organ failure, and death, even in seasons when the vaccine is not a perfect match for circulating strains.
Amid a surge in influenza cases in the US, driven by a new strain popularly dubbed the 'super flu', Dr Mehmet Oz — the administrator of the Centers for Medicare and Medicaid Services — has questioned the effectiveness of the seasonal flu vaccine and suggested alternative ways to “overwhelm” the virus.
In a televised interview on Newsmax, Oz said, “Every year there’s a flu vaccine. It doesn’t always work very well. That’s why it’s been controversial of late.” He added that instead of relying on vaccines alone, people should focus on strengthening their bodies so they can fight off the infection if exposed.
Oz advised measures such as getting adequate sunlight, taking vitamin D and zinc supplements, following what he described as “Make America Healthy Again (MAHA) initiatives” around diet, engaging in physical activity, and prioritising sleep. According to him, these steps would help the body better cope with the flu.
The remarks triggered criticism from medical professionals, who accused Oz of downplaying the effectiveness of vaccination at a time when flu hospitalisations are rising sharply.
So what are the facts— are flu vaccines effective?
Extensive scientific evidence shows that seasonal influenza vaccines consistently reduce the risk of severe illness, hospitalisation, intensive care admission, organ failure, and death. While vaccine effectiveness varies by season and strain match, public health authorities and peer-reviewed studies agree that flu vaccination remains the most effective preventive tool available.
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A CDC-coauthored study published in Clinical Infectious Diseases examined the impact of flu vaccination during the 2022–23 season and found strong protection against severe outcomes. According to the CDC, the study showed that flu vaccination “substantially reduced the risk of serious flu outcomes, including hospitalization, organ failure, and death.” The agency reported that “flu vaccines reduced the risk of hospitalization by 37% overall,” with vaccinated adults aged 18–64 being “47% less likely to be hospitalized with flu” and adults aged 65 and older “28% less likely to be hospitalized.”
The same study found that vaccination reduced the most dangerous complications of influenza. Vaccinated patients were “41% less likely to experience hypoxemia treated with supplemental oxygen,” “65% less likely to have respiratory, cardiovascular, or renal failure treated with acute organ support,” “66% less likely to have respiratory failure treated with invasive mechanical ventilation,” and “69% less likely to be admitted to the ICU.” The CDC said these findings “underscore the importance of flu vaccination during the fall and winter respiratory virus season” and reaffirmed its recommendation that everyone aged six months and older receive an annual flu shot.
Evidence from large pooled analyses further challenges the claim that flu vaccines do not work well. A 2023 systematic review and meta-analysis published on PubMed analysed 123 studies assessing seasonal influenza vaccine effectiveness in people aged 15–64. The authors reported that “the pooled vaccine effectiveness was 48% (95% CI: 42–54)” for randomized controlled trials. When the vaccine strains matched circulating viruses, effectiveness increased to “55.4%,” while even in mismatched seasons, vaccines still showed “39.3%” effectiveness. The study emphasised that “the match between strains included in the vaccine and strains in circulation is the most important factor in the VE (vaccine effectiveness),” noting that protection increases significantly when there is a good match — but does not disappear when there is not.
Concerns that repeated annual flu vaccination may reduce protection have also been examined in depth.
A meta-analysis published in BMC Medicine reviewed observational studies comparing people vaccinated in the current season, prior season, both seasons, or neither. The researchers concluded that “our results support current season vaccination regardless of prior season vaccination,” finding that people who received the current season’s vaccine had greater protection against influenza A(H1N1), A(H3N2), and influenza B than those who were unvaccinated. While effectiveness varied by strain and season, the authors stressed that vaccination in the current season consistently provided meaningful protection compared to no vaccination.
Vaccination has also been shown to reduce the spread of influenza within households. A JAMA Network study examining household transmission found that after influenza was introduced into a home, the estimated effectiveness of flu vaccines in preventing secondary infections among household contacts was 21%. The researchers concluded that “seasonal influenza vaccination is the primary strategy recommended for prevention of influenza illness and its complications,” while noting that additional preventive measures can complement, but not replace, vaccination.
But the new vaccine is not a match for the current dominant strain - so will it still be effective?
One of the reasons people in the US have been increasingly skeptical about this year’s flu shot is that the formulation for the vaccine, which was finalised last February, is not seen as an exact match for the strain that is being held responsible for the sudden surge in flu cases in the country. Experts, however, pointed out that while this year’s flu vaccine may not be a perfect match for the dominant H3N2 subclade K strain, health authorities — including the US Centers for Disease Control and Prevention (CDC) — continue to recommend vaccination to reduce transmission, severe illness, hospitalisation, and death.
This was also echoed by Dr Ashish Jha, former dean of the Brown University School of Public Health, when responding to question on whether the vaccine would work against the new variant, while appearing on CNN. “It depends a little about what you mean by “work.” It’s probably not going to do a great job of protecting you against infection, (or) against the new variant, but it will do a good job of preventing you from getting seriously ill,” he said, while adding that "this year, that mismatch means that the effectiveness against infection is probably only about 30-40 per cent.”
“You still get about a third of lower chance of getting infected. But where the benefit of the vaccine is clear is in preventing ER visits, hospitalisations, and obviously the thing we care most about, which is deaths,” he explained.
So while Dr Oz is correct that flu vaccines do not offer perfect protection and that effectiveness varies from year to year, describing the vaccine as “controversial” because it “doesn’t always work very well” omits crucial scientific context. Across CDC surveillance data, meta-analyses, and real-world hospital studies, flu vaccines consistently reduce the risk of severe disease, hospitalisation, intensive care admission, and death, even in years when circulating strains differ from vaccine strains.
So is Dr Oz right about diet, sunlight, and other lifestyle choices offering protection against the flu?
Dr Oz’s claim has also drawn backlash from the medical experts online.
“Here you see Dr Oz promoting sunlight, vitamin D, zinc, and sleep for the prevention of influenza. What he doesn’t urge people to do is get vaccinated. He knows better. What a shame,” Jonathan Reiner, whose X profile describes as Professor of Medicine and Surgery Interventional Cardiologist, and CNN Medical Analyst, posted on the social media platform.
Lifestyle measures such as adequate sleep, good nutrition, sunlight exposure, and vitamin supplementation may support general health, but there is no clinical evidence showing they can prevent influenza or reduce severe outcomes at a population level. Public health guidance does not position these measures as alternatives to vaccination.
Oz’s comments have also drawn attention because they appear to contrast with his earlier public positions. In the past, he has endorsed routine vaccinations, including the MMR (measles, mumps, rubella) vaccine, and has previously urged people to get flu shots, calling them “more critical than ever” in a 2020 social media post.
Why do his comments matter?
Even if it is an “imperfect protection,” the flu vaccine is still considered the best protection available. This is of particular concern when official estimates show that “there have been at least 7,500,000 illnesses, 81,000 hospitalizations, and 3,100 deaths from flu,” as of December 20, 2025.
This is almost double the number of cases reported by this time, last flu season, which saw “at least 3.1 million illnesses, 37,000 hospitalizations, and 1,500 deaths from flu,” as of December 21, 2024.
This is of particular interest when you look at the fact that, this flu season, approximately 130 million doses of the flu shot have been distributed, which is about 13 million fewer than the doses distributed by this period during the last flu season.
Considering the crisis at hand, it is imperative that people are protected against the preventable disease. And Dr Oz, who has been a popular figure on TV long before he joined the Trump-led administration, is known to be able to shape public opinion as well. A 2022 study showed that “Oz’s endorsement of the MMR vaccine was associated with a shift in acceptance among a segment of his audience.” The researchers highlighted the “persuasive power” of “alternative health media” like Dr Oz’s shows “and its capacity to align the views of its low-knowledge audience members with CDC and FDA-consistent science, should its trusted sources choose to do so.”
This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS.
