Antivax immunologist J. Bart Classen published a paper claiming that mRNA-based COVID-19 vaccines can cause prion disease leading to neurodegenerative diseases like Alzheimer's dementia. What are prions, and can these vaccines cause prion disease? (Spoiler alert: The answer to the second question is almost certainly no. It's speculation based on highly implausible biology.)
Robert F. Kennedy, Jr. published an article claiming that vaccines and glyphosate are responsible for the obesity epidemic. Too bad he cited the work of two longtime antivaccine cranks to support his bogus claim. He's really scraping the bottom of the barrel.