In recent days, several users of the social network Facebook have been sharing the header of an article on the People’s Voice Community website (a misinformation and fake news page) which claims that Japan declared a “national emergency” and then an “explosion”. of cancer cases recorded after administration of the Covid-19 vaccine. “Japan has declared a national emergency due to the explosion of cancer cases across the country caused by mRNA vaccines.” Will it be true?

The article bases the conclusion that Japan is seeing a significant increase (“explosion” is the expression used) in cancer cases in a study called “Increase in age-adjusted cancer mortality after the third dose of mRNA vaccine during the pandemic of Covid-19 in Japan”.

The authors of the study, published by the journal Cureus in early April, they carried out a statistical analysis of available national data on cancer death rates during the pandemic (between 2020 and 2022) compared to the expected pre-pandemic cancer death rates (over a longer period, from 2010 to 2019).


Among the “possible explanations” put forward by Japanese researchers is vaccination against Covid-19. However, the study does not show an increase in cancer deaths among vaccine recipients, nor does it establish any link between mRNA vaccines and cancer. Also There is no evidence that mRNA vaccines increase the risk of death from cancersaid to Reuters Jeffrey Morris, professor of Public Health and Preventive Medicine at the University of Pennsylvania.

The study authors report an increase in cancer cases, but base this conclusion on the fact that cancer mortality rates are not decreasing post-pandemic as they were before the pandemic. And they directly link the mRNA vaccines against Covid-19 with what they call an increase in mortality rates — in fact, what is happening is that the rates are not falling as they did before the pandemic, which can be explained by multiple factors (such as reduced access to oncology healthcare and screenings during the pandemic) and not necessarily vaccines.

In fact, there is no evidence that mRNA vaccines increase the development of cancer. On the contrary. Vaccines of this type are currently being developed to combat various types of cancer.including skin, pancreas or brain.

As for the allegation that Tokyo declared a national emergency because of the “explosion” of cancer cases, the Japanese Embassy in Portugal denies it. “The Japanese Government has not made any factual announcement about this situation, nor has it declared any state of emergency on this matter”, says the Japanese diplomatic representation in Lisbon.

There is not even any reference to any state of emergency or alert on the page of that country’s Ministry of Health, Labor and Welfare, where useful statistics and information are published for the population. Furthermore, there is no news reporting such an emergency declaration by the Japanese government.


No national emergency has been declared in Japan due to mRNA vaccines against Covid-19, as the Japanese Embassy in Portugal confirmed to Observabor. In fact, there is no evidence that these vaccines increase the likelihood of developing cancer.

Thus, according to the Observer classification system, this content is:


In Facebook’s classification system this content is:

FALSE: The main content claims are factually inaccurate. Generally, this option corresponds to “false” or “mostly false” ratings on fact-checker websites.

NOTE: this content was selected by Observador as part of a fact checking partnership with Facebook.

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