These symptoms prompted clinical investigation, and laboratory testing confirmed AVP deficiency. Brain magnetic resonance imaging added structural evidence: the scan showed thickening of the pituitary stalk and absence of the posterior pituitary bright spot. Treatment with desmopressin controlled the patient's excessive urination and thirst.

The report details her clinical course, laboratory results, imaging findings, and follow-up outcomes over an extended period. At 30 months of follow-up, the desmopressin dose had been reduced to 0.025 mg twice daily without recurrence of symptoms. Repeat MRI showed normalization of pituitary morphology.

The authors frame the case as a signal for clinical vigilance rather than evidence of a vaccine safety problem. The 9-valent HPV vaccine is administered widely across the world to reduce the incidence and mortality of HPV infection and its associated diseases, and the report does not alter the evidence base for its use. Instead, it documents a potential post-vaccination adverse event that clinicians might otherwise not consider.

The researchers explicitly caution that causality cannot be established from a single case report. Temporal proximity between vaccination and symptom onset is compatible with an association, but case reports alone cannot distinguish coincidence from a causal effect. The practical message for clinicians is diagnostic awareness.

New-onset polyuria and polydipsia after vaccination should prompt consideration of AVP deficiency in the differential diagnosis, the authors write, since timely recognition allows desmopressin therapy to control symptoms and follow-up imaging to track the underlying changes. The authors conclude that continued clinical attention to potential post-vaccination adverse events remains worthwhile as vaccination programs expand globally.

Subject of Research: Arginine vasopressin deficiency following 9-valent human papillomavirus vaccination

Article Title: Arginine vasopressin deficiency following 9-valent human papillomavirus vaccination: a case report

Article References: Yao, J., Qiu, Y., Zhou, Y., Song, P., Chen, G., & Chen, J. (2026). Arginine vasopressin deficiency following 9-valent human papillomavirus vaccination: a case report. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02672-6

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02672-6

Keywords: arginine vasopressin deficiency, 9-valent HPV vaccine, case report, infundibulo-neurohypophysitis, desmopressin, pituitary MRI, polyuria, polydipsia, vaccine adverse event, BMC Endocrine Disorders, Arginine, vasopressin