Salut, Covid-19, Vacunes

No scientific study showing that vaccines cause cancer has been published

You have sent us a website that publishes the statements of a man who identifies himself as Vladimir Zelenko, and who is presented as a physician, in which he claims that a scientific article has been published showing that vaccinations against covid-19 increase the risk of developing cancer. This is FALSE. A search in the PubMed repository shows no such article and, moreover, cancer associations recommend vaccination of the sick except in specific cases in which it is contraindicated.

"Just last week a paper was published showing that [the covid-19 vaccine] increases the cancer risk".

PubMed, the world's largest repository of biomedical literature, registers 235 results when searching for the terms vaccine, covid-19 and cancer within the text of an article. None of the resulting scientific studies investigate the possibility that a side effect of vaccines is an increased risk of developing a tumour.

What is indeed registered as a rare adverse effect (between one in 100 and one in 1,000 vaccinated) is inflammation of the lymph nodes (or lymphadenopathy). One of the papers given by the search engine warns of the possible risk of confusing this reaction —especially frequent in the axillary area— with a tumour and "complicating the management of cancer patients". The side effect can easily be mistaken for a lymph node metastasis, and there have been cases where the lymph node has been removed because of the confusion in recently vaccinated cancer patients. 

Precisely to avoid this confusion, the American Cancer Society’s recommendation for those with a history of having had or who have cancer is to "talk to your health care team if you are scheduled to have an imaging test (such as a magnetic resonance or computed tomography scan) in the weeks following vaccination", as it may be necessary to delay the test "so that swollen lymph nodes resulting from the vaccine are not confused with cancer". 

Vaccination is recommended

Most of the studies found by the PubMed search engine deal with the debate on whether or not people affected by a tumour or receiving treatment should be immunised against covid-19. According to the American Cancer Society, the risk is mostly related to the inoculation of attenuated virus vaccines: "These living viruses do not cause problems in people with healthy immune systems, but they may not be safe for people with weakened immune systems, so live virus vaccines are generally not recommended for cancer patients. 

However, none of the vaccines approved to date in both the US and Europe would be of this type, so none are discouraged. 

Another matter is the effectiveness of covid vaccines in cancer patients, which could be altered. According to the US National Cancer Institute, "generally, doctors recommend patients with cancer to be vaccinated to protect against infection with severe acute respiratory syndrome type 2 coronavirus (SARS-CoV-2), the virus that causes the 2019 coronavirus disease (covid-19). But some people with cancer may not be as protected as people without cancer. 

In fact, some countries such as the United States or the United Kingdom have authorised a third dose to this group to reinforce immunity, as well as in other at-risk groups with weakened immune systems.


Aquest article és part del projecte "Les Mentides Amenacen la Salut", el primer portal de fact-checking de rumors sobre la covid-19 de Catalunya.

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