Vaccinating girls against HPV does not increase their risk of autoimmune disorders

The National Institute for Health and Welfare (THL) has conducted a study of HPV vaccine administered to girls in the years 2013–2015. The study investigated whether the vaccine increases the risk of autoimmune disorders. There were approximately 241,000 subjects in all. Approximately half of them, or 56 percent, received the vaccine. HPV vaccine prevents HPV viral infection and the precursors of cervical cancer that it causes.

The study showed that vaccinated 11–15-year-olds did not have a greater risk of developing a disorder than non-vaccinated girls of the same age. ‘The study looked at the risk ratio for 38 diseases. These were selected to include disorders for which suspicions have been raised that vaccination could make them more prevalent’, says Chief Physician Hanna Nohynek of THL.

One difficulty of the study is that many of the investigated disorders are very rare, so there were too few cases to allow for reliable statistical analysis and conclusions. Still, Nohynek says the study should serve as a good indication, since it would have revealed any significant increase in these diseases.

The study did indicate an increased risk of a few disorders, such as Guillain-Barré syndrome (nerve root inflammation), erythema nodosum on the shins, and myositis causing progressive muscle weakness. However, the findings were so sparse that the significance of the added risk cannot be assessed.

The study also found that vaccinated subjects had a lower rate of some disorders, such as chronic pain syndrome. However, no conclusions can be drawn about a protective effect from the vaccine due to the low number of observations. For these and other reasons, research will be continued. 

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