Abstract

• In late 2014, the epidemiological data available on the human papillomavirus (HPV) 6/11/16/18 vaccine (Gardasil°) and the HPV 16/18 vaccine (Cervarix°), derived from several million vaccinated girls or young women, showed no link between HPV vaccination and the development of autoimmune diseases or central or peripheral neurological disorders. A few cohort studies have called these results into question.
   
• The detailed results of a large French cohort study focused on 14 types of conditions in girls aged 13 to 16 years, 842 120 of whom received an HPV vaccine. Eleven of these conditions were no more common than in the unvaccinated girls.
   
• A statistically significant association was identified between Guillain-Barré syndrome and HPV vaccine: 1 to 2 additional cases per year per 100 000 vaccinees. A link between Guillain-Barré syndrome and other vaccines has already been observed, making a causal link plausible, despite the lack of an established causal mechanism.
   
• The statistical link between inflammatory bowel disease and HPV vaccines is weak.
   
• The statistical association reported in the French study between thyroiditis and the HPV 16/18 vaccine constitutes low-level evidence, but it is consistent with some other weak evidence. As of early 2016, no significant link has been found between thyroiditis and the HPV 6/11/16/18 vaccine.
  
  
• In practice, in view of the uncertainties, healthcare professionals must present the options to girls and their families in a balanced manner. Girls are faced with a choice between a plausible risk of a very rare event (Guillain-Barré syndrome) in the weeks following vaccination, and the risk of a much less rare event (cervical cancer), which is probably reduced by vaccination but occurs many years later.
   
• As of early 2016, it is reasonable that some girls will choose to be vaccinated in the hope of reducing their risk of cancer. It is also reasonable that others will choose not to be vaccinated due to the risk of Guillain-Barré syndrome, despite its rarity.
   

©Prescrire 1 November 2016

"Human papillomavirus vaccines and Guillain-Barré syndrome: managing uncertainties" Prescrire Int 2016; 25 (176): 265-270. (Pdf, subscribers only)