Severe side effects, or adverse events, are uncommonly reported and have included:
Government, academic, and other public health investigators could not identify the HPV vaccine as the cause of any severe adverse event. There were 117 deaths as of September 2015, none of which could be directly tied to the HPV vaccine. Public health investigators concluded that the HPV vaccine was unlikely to cause these events. Such events occur at a certain rate in any group of tens of millions of people. The vaccination before each adverse event seemed to be a simple coincidence.
- Blood clots
- Seizures
- Guillain-Barré syndrome
- Chronic inflammatory demyelinating polyneuropathy
- Mylgic encephalomyelitis/chronic fatigue syndrome
- Death