Numerous mechanisms may explain how mRNA COVID-19 vaccines may be linked to increased cancer deaths.
Researchers observed “statistically significant increases” in mortality rates of all cancers, especially estrogen-related cancers, following mass vaccination with the third mRNA COVID-19 vaccine, according to a recent paper.
The study, published on April 8 in Cureus, evaluated the impact of the COVID-19 pandemic on age-adjusted mortality rates for 20 different types of cancer in Japan using official statistics on death, SARS-CoV-2 infections, and vaccination rates. The researchers made a startling discovery: There were no excess cancer deaths in Japan during the first year of the pandemic, but they observed a rise in cancer mortality coinciding with mass vaccination.
Japan has the highest vaccination rates, and is now conducting mass vaccinations with a seventh vaccine dose. According to the researchers, after mass vaccination began in 2021, there was a noticeable increase in cancer mortalities coinciding with the first and second COVID-19 vaccine doses.
Following vaccination with a third mRNA vaccine dose in 2022, researchers observed “significant excess mortalities” for all cancers and specifically estrogen and estrogen receptor alpha (ERα)-sensitive cancers, including ovarian, leukemia, prostrate, lip/oral/pharyngeal, pancreatic, and breast cancers. Notably, breast cancer had a “significant deficit mortality” in 2020 but shifted to excess mortality in 2022 following the rollout of the third vaccine dose.
Other than pancreatic cancer, which was steadily rising before the pandemic, the other five types of cancers were on a downward trend. Still, all six types of cancers exceeded predicted mortality values in 2021, 2022, or during both years.
Additionally, four types of cancers associated with the most deaths—lung, colorectal, stomach, and liver cancers—were declining before the 2020 pandemic. However, the rate of decline slowed after the COVID-19 vaccine rollout.
Significant Shift in Excess Mortality
Prior to the COVID-19 pandemic, from 2010 to 2019, researchers observed decreasing mortality trends for people of all ages except those aged 90 and over. Even in 2020, researchers continued to see declining mortality rates in most age groups except for those aged 75 to 79.
