No increased risk of chronic fatigue syndrome after HPV vaccination

Girls receiving one or more doses of HPV vaccine have no greater risk of chronic fatigue syndrome/myalgic encephalomyelitis (CFS / ME) than unvaccinated girls. This is shown in a new major study from the Norwegian Institute of Public Health.

The study is part of the national surveillance of the HPV vaccination programme and includes data from more than 175,000 girls in the first six birth cohorts who were offered the vaccine in 7th grade. 145,000 of these received one or more doses of HPV vaccine.

"This is a major study where we have investigated the association between HPV vaccination and chronic fatigue syndrome. The incidence of this disease has increased in Norway, but we found no association with HPV vaccination," says first author of the study, Berit Feiring from the Department of Infectious Disease Epidemiology and Modelling at the Norwegian Institute of Public Health.

Offered to girls in 7th grade since 2009

Human papillomavirus (HPV) is a virus that can cause infection in the cervix. Persistent HPV infection is a necessary cause of cervical cancer.

The HPV vaccine Gardasil protects against 4 different HPV genotypes (6, 11, 16 and 18) and has been offered to girls in 7th grade since 2009.

Information about CFS / ME and other diagnoses from the Norwegian Patient Registry (NPR) was linked with information about HPV vaccination from the Norwegian Immunisation Registry (SYSVAK).

The study has adjusted for factors that may affect the association between vaccination and CFS / ME, such as region of residence, country background, parental education and previous hospital visits among the girls.

Results of the study

• Girls who have received one or more doses of HPV vaccine have no greater risk of CFS / ME than girls who have not received HPV vaccine.
• The study also shows that the number of CFS / ME cases in Norway has increased in the period 2009-2014. The data for this part of the study includes all Norwegian children and adolescents, aged 10-17 years, during the study period, in total more than 800,000 persons. About two thirds (67 per cent) of those diagnosed are girls. However, the increase is similar in both sexes, although girls are more frequently diagnosed than boys. The reason for the increase is unknown.