Rising cancers in young adults preceded pandemic, unrelated to COVID-19 or vaccines, contrary to Patrick Soon-Shiong’s claims in Tucker Carlson interview

While myths and falsehoods about diseases and treatments aren’t new, the COVID-19 pandemic represented a turning point in the landscape of health misinformation. The uncertainty that accompanied the pandemic, combined with the reach of social media platforms, created fertile ground for health misinformation to flourish online.

Even before a COVID-19 vaccine became available in December 2020, false and unsubstantiated claims targeting vaccine ingredients, effectiveness, and potential side effects were already widespread on social media. In 2022, the term “turbo cancer” began trending on Google searches linked to a narrative connecting COVID-19 vaccines with an alleged increase in aggressive, rapidly progressing cancers among young adults.

Years later, this narrative continues to circulate, as evidenced by a 26 March 2025 interview on The Tucker Carlson Show featuring Patrick Soon-Shiong, a surgeon and owner of the Los Angeles Times. According to the video description on Carlson’s YouTube Channel, Soon-Shiong warned that “Covid, and the vaccines that didn’t stop it, are likely causing a global epidemic of terrifyingly aggressive cancers”. At the time of writing, the interview had been watched over one million times on YouTube.

Indeed, Soon-Shiong talked about an increase in incidence (rate of new cases over a period of time) of certain types of cancer, like pancreatic, ovarian, and colon cancer among young people. “Is it by coincidence that post COVID infection, post COVID vaccine, we’re seeing all these events where we know the spike protein goes there? I don’t think so,” he said”.

The host of the show, Tucker Carlson, has made false claims regarding the safety and effectiveness of COVID-19 vaccines in the past. Meanwhile, Soon-Shiong endorsed the nomination of current U.S. Department of Health and Human Services secretary Robert F. Kennedy Jr., who for many years led the anti-vaccine organization Children’s Health Defense.

Science Feedback previously explained why claims linking COVID-19 vaccines with cancer are unsubstantiated. The U.S. National Cancer Institute (NCI) and the American Cancer Society (ACS) have stated that no evidence suggests COVID-19 vaccines cause cancer, make it more aggressive, or more likely to come back.

And while epidemiological data does show a worrisome increase in certain types of cancer among young adults, this trend started decades before the COVID-19 pandemic, as we will show below. This directly contradicts the claim that COVID-19 or COVID-19 vaccines are driving this phenomenon.

Below, we discuss what experts believe are the most plausible causes for this increase and why COVID-19 vaccines aren’t among them.

Cancer diagnoses in adults younger than 50 have been increasing since the 1990s

Every year, the ACS, the U.S. Centers for Disease Control and Prevention (CDC), the NCI, and the North American Association of Central Cancer Registries produce an updated report on cancer burden in the U.S. This report also estimates the number of new cancer cases and deaths for the upcoming year.

The latest ACS report, released in 2025, indicated that while cancer mortality continues to decline due to reduced smoking, earlier detection, and improved treatment, the number of new cases increases and is estimated to exceed two million in 2025^[1].

The report also showed that new cancer cases were rising more rapidly among people under 50 (typically defined as early-onset cancer) compared to older adults, notably in women. This increase was primarily due to breast and thyroid cancers in women, which together accounted for almost half of all new cases in this age group. But early-onset cases of leukemia, colorectal, testicular, and kidney cancers in men also increased.

Trends in cancer incidence worldwide can vary widely and be difficult to compare. But one study published in BMJ in 2023 shows that the rise in early-onset cancer isn’t limited to the U.S. but is a global phenomenon. By analyzing data from the Global Burden of Disease (GBD) study from 1990 to 2019, the BMJ study found that the rate of early-onset cancer started rising in the 1990s, particularly in countries with high-middle and middle socioeconomic development^[2]. The study estimated that by 2030, the number of new cancer diagnoses in adults under 50 may increase by roughly 30% globally.

Another study led by the ACS and published in Lancet Oncology in 2025 focused specifically on colorectal cancer. It found that, from 2007 to 2017, new diagnoses rose in 27 of the 50 countries and territories analyzed, which were primarily high-income Western countries, including the U.S., Australia, New Zealand, Canada, and several European countries^[3].

During the interview, Soon-Shiong mentioned reports of people who were in cancer remission (when a cancer patient no longer shows cancer symptoms) and “are now getting back to cancers and very rapidly progressing”. He also talked about cases of colon and metastatic pancreatic cancers in children, mentioning the term “turbocharged cancer”. But are these early-onset cancers more aggressive than those in older adults as Soon-Shiong and others suggested?

For one thing, cancers in younger people are often found at a more advanced stage just because young people don’t generally undergo routine cancer screening. But according to oncologists at Yale Medicine, some types of cancer, including breast and colorectal cancer, do tend to be more aggressive and evolve more rapidly in young individuals compared to older adults. Researchers are still investigating the reasons behind this difference in cancer progression.

In summary, the evidence does indicate that certain types of cancer are on the rise among young adults. Some might also be more aggressive when they affect younger people. However, this trend didn’t start with the pandemic, as some have claimed. Instead it has been ongoing for the past three decades. Therefore, the phenomenon can’t be attributed to COVID-19 or COVID-19 vaccines.

Why are cancer rates increasing among younger adults?

It is important to note that, despite the rise, cancer in young people remains uncommon overall. The reason is that advanced age is the main risk factor for cancer, so the vast majority of all cancers still occur in people over 50. In the U.S. and Europe, adolescents and adults under 40 account for roughly 5% of all new cancer diagnoses^[4]. This is precisely why the increase in younger people is unexpected. It also means that diagnoses are likely to continue rising as these younger generations age.

Over the past few decades, improvements in diagnostic technology have enabled earlier detection of several types of cancers, likely contributing to the observed increase in early-onset cancers. For example, the ACS noted that thyroid cancer was a major driver of the increase, along with breast cancer. Thyroid cancer is one of the most common types of cancer in adolescents and adults under 40 and has steadily increased (about 4% per year) since the late 1990s. Experts partly attribute this increase to the use of diagnostic imaging and fine-needle aspiration biopsy, which has improved the detection of cases with no obvious symptoms^[5].

However, researchers agree that early detection alone can’t fully explain the phenomenon, indicating a genuine increase in cases.

To better understand the underlying causes of this trend, the NCI included it in its 2020 Provocative Questions Initiative, a program running from 2011 through 2021 that funded studies looking into “perplexing and underexplored areas” of cancer research. Although there is yet no clear explanation for the rising cancer rates among younger people, experts believe there are likely multiple contributing factors rather than a single culprit.

Changes in the incidence of a disease between generations suggest that the cause might be environmental. Many factors, including diet, lifestyle, and environmental pollutants, have changed significantly since the mid-20th century, and fetal or early-life exposures to some of them might influence the risk of some types of cancer later in life^[6].

Andrea Cercek, a gastrointestinal oncologist and co-director of the Center for Young Onset Colorectal and Gastrointestinal Cancer at the Memorial Sloan Kettering Cancer Center explained, “[t]he working hypothesis is that there is an environmen­tal exposure—or multiple exposures—that people born starting in the 1950s came in contact with”. It is possible that such exposures “began in the 1960s or ’70s and have been continuously present since then,” she added.

Some candidates that researchers have been looking at are known risk factors for cancer to which people’s exposure has varied in the past few decades. For instance, in the U.S., cigarette smoking among young people peaked between 1991 and 1997, although it declined markedly after that period. Alcohol consumption has steadily increased since the mid-1990s.

Another known risk factor to take into account is obesity, which has sharply increased in the U.S. and many other developed countries since the early 20th century, largely due to unhealthy diets and sedentarism. The International Agency for Research on Cancer (IARC), part of the World Health Organization, recognizes obesity as a cause of at least 13 different types of cancer and some studies have associated it to an increased risk of early-onset colorectal cancer[6].

While known risk factors may be partly responsible for the rise of early-onset cancer, researchers are also investigating whether yet-unidentified environmental factors might be playing a role. In an article for The New York Times, several oncologists discussed the potential impact of certain environmental toxins or changes in the microbiome—the collection of microorganisms that live in our body—on the risk of colorectal cancer.

Researchers have found that antibiotics or a diet rich in ultra-processed foods can drastically change the gut microbiome in ways that may potentially increase the risk of cancer. In fact, greater antibiotic exposure has been linked to several types of cancers, and its use has risen markedly globally since the 2000s^[7]. Both factors are currently under investigation.

No evidence linking COVID-19 vaccines with the increase in early-onset cancer

As the ACS and the NCI have stated, no evidence suggests that COVID-19 vaccines cause cancer. And several reasons explain why the increase in early-onset cancers isn’t attributable to COVID-19 vaccination.

Firstly, while the 2025 ACS report offers valuable insights into cancer trends in the U.S., the data it includes typically lags two to four years behind the report’s release. This delay is due to the time needed to collect, verify, and input the data into databases. Thus, trends in new diagnoses presented in the report are based on data collected up to 2021, only one year after the rollout of COVID-19 vaccines.

But for known cancer risk factors, the time lag between exposure and cancer diagnosis is generally lengthy, up to decades, as shown by tobacco smoke and UV radiation, for example. This makes it extremely unlikely that cancer would develop only one year after exposure, as claimed for COVID-19 vaccines, and the ACS report would capture such changes.

And even in cases where more current data is available, for example in the Surveillance, Epidemiology, and End Results Program conducted by the NCI which monitors the most recent cancer trends, we don’t see a significant rise in new cancer diagnoses that correlates with COVID-19 vaccination.

Secondly, even if the incidence of early-onset cancer has actually increased following COVID-19 vaccination, this fact alone doesn’t prove that the vaccines caused the rise. This is because there were several pandemic-related changes unrelated to vaccination that could have influenced the number of new cancer diagnoses in the years following vaccine rollout.

For example, the pandemic caused significant disruptions in health services that negatively affected cancer screening^[8,9], resulting in an estimated one million missed cancer diagnoses across Europe. In the U.S., missed and delayed screenings led to a drop in new diagnoses in 2020 compared to previous years, with reported reductions ranging from 10% to 65%, depending on the study and the type of cancer^[10-12].

Lisa Richardson, the director of the CDC’s Division of Cancer Prevention and Control, told CNN in 2023 that an uptick in cancer diagnoses would be expected in the subsequent years:

“What we might see is that there are actually more cases of cancer, because people caught up. But it’s not truly an increase. It’s just a catch up of what was there that we didn’t diagnose during 2020.”

Third, there is no known scientific mechanism by which mRNA vaccines could change our DNA and cause cancer. Claims suggesting otherwise often rely on anecdotal evidence and flawed analyses that lack adequate scientific backing, as Science Feedback showed in earlier reviews.

There is also no evidence to suggest that vaccines in general cause cancer. On the contrary, several vaccines effectively protect from certain types of cancer by preventing infection with cancer-causing viruses. Interestingly, researchers have reported at least two cases of cancer remission following vaccination with an mRNA COVID-19 vaccine^[13,14].

COVID-19 vaccination is particularly important in people with cancer, as the disease itself and some cancer treatments can weaken the immune system, putting the person at a higher risk of developing severe illness^[15-18].

Can COVID-19 cause cancer?

While vaccination isn’t associated with cancer, we know that some viruses can cause cancer. Currently, the IARC recognizes seven viruses and one bacterium as cancer-causing in humans, which collectively account for roughly 20% of all cancers.

So far, research is inconclusive about whether SARS-CoV-2 has oncogenic potential and, if it does, whether it initiates cancer or simply changes its progression.

Scientists investigating long Covid have hypothesized that persistent inflammation triggered by SARS-CoV-2 fragments lingering in some people^[19] may facilitate cancer development and spread (metastasis)^[20,21]. Supporting this hypothesis, some studies have shown an association between SARS-CoV-2 infection, particularly severe illness, and an increased risk of various types of cancer^[22,23].

Adding more complexity to the matter, one study published in Scientific Reports in 2023 suggested that the observed association between COVID-19 and cancer may not be due to a causal relationship between the two. Instead, it proposed the associations may reflect undiagnosed cancers that increase the person’s vulnerability to developing severe COVID-19^[24].

Conversely, other studies suggest that the immune system’s reaction to a SARS-CoV-2 infection may actually help fight cancer. Some researchers have reported instances of cancer regression following SARS-CoV-2 infection^[25], an effect that has also been observed in laboratory mice and human cells^[26].

In other words, the jury is still out about whether SARS-CoV-2 has the potential to cause cancer or help it proliferate. Answering that question with certainty will likely require years of research.

Over two-thirds of global cancer cases are attributable to modifiable risk factors that can be prevented, including tobacco and alcohol use, unsafe sex, and unhealthy dietary patterns^[27]. Consequently, the ACS recommends several steps a person can take to help reduce their cancer risk. These steps include eating a healthy diet and staying at a healthy weight, avoiding tobacco products, and staying active throughout life.

In addition, vaccinating against human papillomavirus (HPV) can help prevent cervical cancer and other types of cancer caused by HPV. Finally, keeping up-to-date with recommended cancer screenings can help detect cancer early, improving the chances of treatment and recovery.

Conclusion

Some types of cancer are on the rise in adults under 50, particularly in women, and some tend to be more aggressive in younger individuals compared to older adults. However, this trend began over three decades ago, so this epidemiological evidence is inconsistent with claims that this trend only occurred following the pandemic and that COVID-19 vaccines are to blame.

The causes for this increase are unclear, but experts believe changes in lifestyle and environmental exposures in the generations born in the 1990s and later might play a role. Some factors that are being investigated include diet, lack of physical activity, and known risk factors for cancer like tobacco and alcohol use. The role of environmental toxins that haven’t been linked to cancer yet is also being investigated.

Overall, the idea that the COVID-19 pandemic or the vaccines will lead to a “global epidemic” of aggressive cancers in young people lacks scientific evidence to support it. No evidence indicates that early-onset cancers surged since the COVID-19 pandemic, nor that vaccinated people are more likely to develop cancer than unvaccinated individuals. There is also no known mechanism or data that connects COVID-19 vaccines to cancer. More research is needed to assess whether SARS-CoV-2 infection might impact cancer risk later in life.

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