Possible increases in cancer rates and lower life expectancy in 2021 are primarily driven by effects of COVID-19, not vaccination

“Cancer rates have increased since the introduction of the COVID-19 shots”, which “is driving down U.S. life expectancy”
The direct and indirect effects of the COVID-19 pandemic have caused a decline in life expectancy in many countries, including the U.S. In addition to the enormous pressure that COVID-19 itself placed on healthcare systems worldwide, most of the countries also implemented strict control measures to minimize the spread of the virus. Altogether, the pandemic resulted in significant disruption to healthcare, leading to delays in cancer screening, diagnosis, and treatment that may have worsened health outcomes in cancer patients.

FULL CLAIM: “Cancer rates have increased since the introduction of the COVID-19 shots”, which “is driving down U.S. life expectancy”; “COVID-19 boosters may be causing aggressive metastatic cancers”


On 6 January 2023, Children’s Health Defense published an article by Joseph Mercola claiming that “Cancer rates have increased since the introduction of the COVID-19 shots” and that “COVID-19 boosters may be causing aggressive metastatic cancers”. According to the social media analytics tool Buzzsumo, the article received more than 15,000 engagements on social media platforms, including over 12,500 shares on Twitter.

Mercola has repeatedly made inaccurate and misleading claims about COVID-19 and COVID-19 vaccines, as multiple reviews by Health Feedback documented. Similarly, Children’s Health Defense has also published vaccine misinformation before. Media Bias/Fact Check labels it as “a strong conspiracy and quackery level advocacy group that frequently promotes unsupported claims”.

Below, we will analyze the claims in the Children’s Health Defense article and explain why it is misleading and unsupported by scientific evidence.

No evidence suggests that COVID-19 vaccines cause cancer or worsen cancer progression

Mercola’s article cited a letter by oncologist Angus Dalgleish published in the Daily Sceptic on 26 November 2022. Addressing the British Medical Journal’s editor-in-chief, Dalgleish claimed to have observed new cancer cases or worsening disease among people who had received COVID-19 vaccine boosters.

Based on personal observations of patients and colleagues, Dalgleish mentioned a few cases of people who had developed leukemia, non-Hodgkin’s lymphoma, and metastatic cancer after receiving a COVID-19 vaccine booster.

However, claims based on anecdotes are unreliable without further data that support them. As neurologist Steven Novella explained on Science-Based Medicine, anecdotes are subject to multiple biases, including the fallibility of human memory, reporting bias, and confirmation bias, which make them extremely difficult to interpret and attribute to a specific cause. Therefore, Dalgleish’s testimony alone is insufficient evidence to support the claim that COVID-19 vaccines cause cancer or make it worse.

Cancer was already a leading cause of death in the U.S. before the pandemic, only behind heart disease. While definitive statistics on cancer are only available up to 2019, provisional data suggest an increase in the number of new cancer cases in 2021. However, experts attribute this to delays in cancer screening, diagnosis, and treatment due to healthcare disruptions during the COVID-19 pandemic[1-3].

As the U.S. National Cancer Institute explains, there is currently no evidence suggesting that COVID-19 vaccines increase cancer risk or worsen the clinical outcome of patients who already have the disease.

While some cancer treatments might weaken the immune response to vaccination, COVID-19 vaccines remain effective against severe illness in people with cancer[4], who are at a higher risk of severe COVID-19 and death[5,6]. Therefore, public health authorities, including the U.S. Centers for Disease Control and Prevention, recommend that people who have cancer or had cancer in the past should “stay up to date with COVID-19 vaccination and booster doses”. The American Cancer Society supports this recommendation.

A retracted study by Jiang and Mei didn’t demonstrate that COVID-19 vaccines cause cancer

Mercola’s article referred to an August 2022 article in The Exposé as “scientific proof” that “COVID jab causes cancer”. This article, in turn, cited a retracted study published by Hui Jiang and Ya-Feng Mei in October 2021 in the journal Viruses[7] to claim that “the Covid-19 mRNA injections can cause cancer of the ovaries, pancreas and breast”. But as Health Feedback explained in an earlier review, the study by Jiang and Mei didn’t demonstrate such a thing.

Briefly, the authors artificially produced high amounts of the SARS-CoV-2 spike protein—a strategy known as overexpression—in human-derived laboratory cells. The researchers detected the spike protein in the cell nucleus, the cell compartment where genetic material is stored. They also observed that the protein reduced cellular mechanisms of DNA damage repair.

Jiang and Mei proposed that this mechanism might mediate the poorer adaptive immune responses observed in patients with severe COVID-19[8]. This type of immunity develops in response to a foreign substance or invader—such as a virus— and involves specialized immune cells and antibodies that target the invader. Therefore, adaptive immunity is important for preventing future infections and for clearing viruses in already-infected patients. The authors conjectured that the spike protein produced after COVID-19 vaccination might also impact the adaptive immune response as a side effect.

But contrary to what Mercola and the Exposé articles claimed, this study didn’t address whether the spike protein from COVID-19 vaccines had the same effect as the viral protein, nor whether this mechanism led to cancer. Furthermore, the authors used a model of artificial overexpression in laboratory cells, which doesn’t necessarily represent what’s happening in the much more complex human body.

In May 2022, the study was retracted for containing statements that lacked adequate experimental support. The retraction note explained:

“[S]tatements regarding the effect of the spike protein on the adaptive immunity are misleading as in this article no experiments related to the adaptive immunity were performed, and the full-length spike-based vaccine was not studied. Therefore, conclusions related to vaccine safety are not validated and lacked experimental support.” [emphasis added]

In short, the articles in the Exposé and Children’s Health Defense misrepresented the results of the study by Jiang and Mei, which doesn’t demonstrate that COVID-19 vaccination leads to cancer. As Health Feedback explained in earlier reviews, there is currently no evidence suggesting that the COVID-19 vaccines weaken the immune system or cause cancer.

Life expectancy decreased in 2021, mostly driven by COVID-19 deaths

In the article, Mercola juxtaposed the introduction of COVID-19 vaccines in 2021 with data showing a decline from 78.8 to 76.4 years in life expectancy in the U.S. by the end of 2021. Such framing clearly implies that the COVID-19 vaccines are behind this drop. Further strengthening this idea, the article also pointed out that the leading causes of death in 2021 were heart disease, cancer, and COVID-19, and claimed the first two were “potential side effects of the COVID-19 jabs”.

Provisional mortality data from the U.S. National Center for Health Statistics (NCHS) shows that life expectancy at birth in the U.S. indeed declined by almost a year in 2021 (76.1 years) compared to 2020 (77 years). But as Figure 1 shows, an even larger decline of almost two years occurred already from 2019 to 2020, before COVID-19 vaccines were available. Overall, life expectancy fell by 2.7 years between 2019 and 2021, returning to levels from 25 years ago.

Figure 1. Life expectancy at birth in the U.S. from 2000 to 2021. Estimates of life expectancy in 2021 are based on provisional mortality data and might be subject to change. Source: U.S. National Center of Health Statistics. Data retrieved on 13 January 2023.

Contradicting the claim that the side effects of COVID-19 vaccines caused the decline in life expectancy, NCHS data shows that COVID-19 was by far the leading contributor in 2020 and 2021 (Figure 2).

Figure 2. Leading causes of death contributing to the decline in life expectancy in the U.S. from 2020 to 2021, presented as a percentage of its contribution. Negative values represent increases in mortality that contributed to a shorter life expectancy compared to previous years, such as COVID-19 and unintentional injuries. Positive values represent reductions in mortality compared to previous years, such as influenza and chronic lower respiratory diseases (CLRD). Estimates for 2021 are based on provisional data, which are subject to change as additional data are received. Source: U.S. National Center of Health Statistics.

Likewise, one study published in PLOS One in August 2022 found that COVID-19 deaths were the primary cause contributing to the decline in life expectancy in the U.S. in 2021[9].

The study showed that increases in other causes of death, including drug overdose, heart disease, and diabetes, further contributed to this decline. However, the authors attributed at least part of these increases to the delays in cancer diagnosis and treatment mentioned above. Similarly, the U.S. National Institute on Drug Abuse reported that the pandemic exacerbated substance use and drug overdose since early 2020, although this cause of death was increasing rapidly even before COVID-19.

Another study published in the journal Nature Human Behavior in October 2022 showed that most countries in Europe also experienced a decline in life expectancy from 2020[10]. Although the decline was more pronounced in countries with lower pre-pandemic life expectancies, the study found that “COVID-19 was the largest contributor to the 2021 [life expectancy] deficit” in 28 of the 29 countries analyzed, including the U.S., most of Europe, and Chile.


Claims that COVID-19 vaccines cause cancer are unfounded. There is no evidence suggesting that COVID-19 vaccines lead to cancer, make it more aggressive, or increase mortality. While life expectancy declined in 2020 and 2021 and cancer rates might have increased, data indicates that this effect was mostly driven by COVID-19 itself and the disruption it caused in healthcare systems.



Published on: 13 Jan 2023 | Editor:

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