Health problems regarded as side effects of cervical cancer vaccines have also been found in people who did not have the vaccinations, according to a health ministry study.
The study found that the share of people across Japan with such health problems among those who received vaccinations stood at 27.8 per 100,000, while the number of unvaccinated people with the same symptoms came to 20.4 per 100,000. Among male patients not subject to the vaccination, 20.2 per 100,000 suffered from such symptoms.
The ministry denied that the results will immediately lead it to restart recommendations for the vaccinations, which have been suspended since 2013 due to the perceived side effects. The study did not determine whether there is causality between the vaccinations and the symptoms, ministry officials said.
The study, conducted by a research team that included Tomotaka Sobue, a professor at Osaka University, covered patients in all hospitals across Japan with more than 200 beds, and half of the smaller hospitals.
Between July and December 2015, the team looked for patients then 12 to 18 years old who had the symptoms for more than three months and also had problems working or attending school. Further details of the symptoms were requested from hospitals answering that they had such patients.
The survey showed that while almost the same share of vaccinated and unvaccinated people experiencing the symptoms had headaches and stomachaches, vaccinated patients suffered more from systemic pain, gait disturbance, tiredness and a weakening grip.
The group age composition was different between vaccinated and unvaccinated populations. In addition, vaccinated patients were more likely to report their symptoms, as they were aware of news involving cervical cancer vaccines that had made headlines in the past.
Due to these factors, the frequency of people developing such symptoms cannot be compared simply between the two groups, a ministry official said.