Hviid, Anders, Thorsen, Nicklas M, Valentiner-Branth, Palle et al. · BMJ (Clinical research ed.) · 2020 · DOI
This study examined whether the HPV vaccine (used to prevent cervical cancer) was linked to ME/CFS, complex regional pain syndrome, or POTS in over 1.3 million Danish girls and women. Researchers found no evidence that the vaccine caused these conditions—the rates of these illnesses were similar whether or not girls received the vaccine.
Given ongoing public concerns about HPV vaccination and autonomic dysfunction, this large-scale registry study provides reassuring population-level evidence regarding ME/CFS and related conditions. For patients questioning vaccine safety in relation to illness onset, this evidence helps inform shared decision-making with healthcare providers.
This study does not prove vaccines cannot trigger ME/CFS or autonomic conditions in any individual—it shows population-level rates were not elevated. The study cannot exclude smaller increased risks (up to 32% above baseline) due to statistical power limitations. Registry-based diagnosis codes may miss cases or misclassify conditions, so true associations in undiagnosed populations cannot be ruled out.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Hviid, Anders, Thorsen, Nicklas M, Valentiner-Branth, Palle, Frisch, Morten, & Mølbak, Kåre (2020). Association between quadrivalent human papillomavirus vaccination and selected syndromes with autonomic dysfunction in Danish females: population based, self-controlled, case series analysis.. BMJ (Clinical research ed.). https://doi.org/10.1136/bmj.m2930
BibTeX
@article{mecfsatlas-hviid-2020-association-between,
author = {Hviid, Anders and Thorsen, Nicklas M and Valentiner-Branth, Palle and Frisch, Morten and Mølbak, Kåre},
title = {Association between quadrivalent human papillomavirus vaccination and selected syndromes with autonomic dysfunction in Danish females: population based, self-controlled, case series analysis.},
journal = {BMJ (Clinical research ed.)},
year = {2020},
doi = {10.1136/bmj.m2930},
note = {PubMed: 32878745},
url = {https://www.mecfsatlas.com/evidence/hviid-2020-association-between},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/hviid-2020-association-between
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