Daily Mail corrects article about Covid vaccines and cancer

The Daily Mail has corrected an article that incorrectly claimed “Korean researchers said they found proof the [covid vaccines] raised the risk of six types of cancer including lung, breast and prostate.”

In fact the Korean researchers in question said the opposite. They said they had found an association between the vaccines and various cancers, but they did not have proof the vaccines caused a higher risk of cancer, as they “did not establish causal relationships”.

Indeed, as we have said recently, there is no credible evidence that the Covid vaccines do cause cancer, and many reasons to doubt that the Korean data suggests otherwise.

What the Mail said

In an article published online on Monday 29 September, the newspaper reported that a group of Korean researchers had published a study saying that the Covid vaccines might “raise the risk of certain cancers”.

The study, which was widely shared by people we have previously fact checked for sharing vaccine misinformation, was published as a letter to the editor of Biomarker Research. It described some statistical work the researchers had done using data from the Korean National Health Insurance database.

In simple terms, they found that people who had been vaccinated against Covid were more likely than those who hadn’t been vaccinated to be diagnosed with several types of cancer within a year.

They concluded: “COVID-19 vaccination could be associated with an increased risk of six specific cancer types.” Although a supplementary file supporting the research clearly says: “our findings do not establish causal relationships”.

This is why the Mail was wrong to say that the Korean researchers claimed they had found proof that the vaccines raised the risk of cancer. After Full Fact got in touch, the newspaper corrected the article to say the researchers “said they found evidence of an association”.

This association is not good evidence the jabs cause cancer

The Korean research is actually very far from proof that the vaccines caused those extra cancer cases.

For one thing, as an expert says lower down in the Mail’s article, it is not medically plausible for something to cause solid cancer (a cancer that develops as a lump) to develop to the point where it would be diagnosed within a year.

Dr Benjamin Mazer, an assistant professor of pathology at Johns Hopkins University, told the Daily Mail: 'No carcinogen can induce cancer that quickly. Mutations take time to accumulate and cells take time to replicate.

'The outcome measured is not the development of cancer but the diagnosis of cancer.”

Indeed the researchers themselves say the same in a supplementary file: “As most solid tumours require more than 1 year to develop, our one-year follow-up period is relatively short for evaluating cancer incidence, and the possibility of reverse causation or surveillance bias cannot be excluded.”

Reverse causation would mean things working the other way around, with people at a higher risk of cancer, perhaps because they have other health problems, being more likely to get vaccinated.

Surveillance bias would mean people who are more likely to get vaccinated being more likely to get tested or screened for cancer, making them also more likely to be diagnosed with it in the short term—but not actually more likely to develop the disease.

Nor, in the big picture, is there any sign of a large increase in these cancers in Korea following the rollout of the Covid vaccines—which you would expect if the vaccines were really causing more of them. The Mail article also noted this lower down.

As Cancer Research UK told the Guardian last month: “There is no good evidence of a link between the Covid-19 vaccine and cancer risk. The vaccine is a safe and effective way to protect against the infection and prevent serious symptoms.”