A Long-Term Observation on the Possible Adverse Effects in Japanese Adolescent Girls after Human Papillomavirus Vaccination

In Japan, a significant number of adolescent females noted unusual symptoms after receiving the human papillomavirus (HPV) vaccination, of which the vast majority of them were initially diagnosed with psychiatric illnesses because of the absence of pathologic radiological images and specific abnormalities in laboratory test results. Later these symptoms were thought to be adverse effects of HPV vaccination. However, a causal link between HPV vaccination and the development of these symptoms has not been demonstrated. Between June 2013 and March 2021, we examined 200 patients who noted various symptoms after HPV vaccination. In total, 87 were diagnosed with HPV vaccination-related symptoms based on our proposed diagnostic criteria. The clinical histories of these 87 patients were analyzed. The age at initial vaccination ranged from 11 to 19 years old (mean ± SD: 13.5 ± 1.5 years old), and the age at the first appearance of symptoms ranged from 12 to 20 years old (mean ± SD: 14.3 ± 1.6 years old). The patients received an initial HPV vaccine injection between May 2010 and May 2013, but the first affected patient developed symptoms in October 2010, and the last affected developed symptoms in October 2015. A cluster of patients with a post-HPV vaccination disorder has not appeared in Japan during the last five years. Our study shows that, in Japan, the period of HPV vaccination considerably overlapped with that of a unique post-HPV vaccination disorder development. This disorder appears as a combination of orthostatic intolerance, chronic regional pain syndrome, and cognitive dysfunction, but its exact pathogenesis remains unclear