Morbidity before HPV vaccination is different for women with and without presumed adverse reactions to the vaccine

Many women with perceived severe adverse reactions to the HPV vaccination showed symptoms before the first vaccination.

Higher occurrence of diseases in the digestive system and the musculoskeletal system before vaccination is among the issues that contrast the group of women who reported assumed adverse reactions to the HPV vaccine from vaccinated women not reporting adverse reactions.

These are findings from a Danish register-based study. Part of the study was presented in April 2016 at the Nordic Vaccine Meeting in Iceland but the study is now published in PLOS ONE and can be read as a whole.

The findings from a highly mentioned Danish register-based study show that the experience of possible adverse reactions to the HPV vaccine can be related to the woman’s morbidity before the vaccination.
The study compared health data from 2 years prior to the vaccination for HPV- vaccinated women, and it reports that the group of women who have reported adverse reactions to the vaccine differs from women without adverse reactions in several ways.

They were more often in contact with their GP. They had more tests, and they were more often referred to a physical therapist or a psychologist. Moreover, they were more likely to have a diagnosis from a hospital for a range of diseases and symptoms.

“When looking at the groups as a whole there is a difference in contact with doctors and in morbidity. It shows that many women had medically unexplained symptoms and diagnosis ressembling those that later present as assumed adverse reactions. Pre-vaccination morbidity should be taken into account in the evaluation of vaccine safety signals and possible adverse reactions”, says MD DMSc Kåre Mølbak, Director at Statens Serum Institut, who is responsible for the study.

Preliminary results from the study were presented in part in connection with the Nordic Vaccine Meeting in Iceland in the spring. Now the study is published by PLOS ONE and the conclusions are available in details.

Results based on analysis of data from more than 160,000 vaccinated women

The study includes all 316 women who had reported assumed adverse reactions to the HPV vaccine before the summer of 2015, when the collection and analysis of data began. The 316 women were compared with other women, who were vaccinated in the same period of time – but who did not report adverse reactions. All in all 163,910 women.

The researchers have been able to compare data about their health care-seeking patterns; e-mail consultations, visits at specialists, psychologists, psychiatrists, physical therapists etc. For all these types of consultations – apart from dental consultations – the group of women with reported adverse reactions had more contacts before first vaccination than the other group.

The researchers could also see data about a range of diagnoses from contacts with hospitals in the years prior to the vaccination. Some of the most important differences were that the group of women with reported adverse reactions had a closer contact with their GP and were more often referred to physical therapy, chiropractor, psychologist and psychiatrist before receiving their first vaccine. Moreover, there was a long range of hospital diagnoses that were given prior to the vaccine more often to this group than in the reference group. This especially applies to diagnoses from the digestive system, muscles and connective tissue and an overrepresentation of unexplained medical symptoms including pain and fainting. They also had more diagnoses from the hospital because of minor injuries.

“The study shows that many of the affected women had different symptoms even before they received their first HPV vaccine. This does not rule out that some individual women had adverse reactions to the vaccine. It is also not possible to rule out that the vaccine in certain situations may have triggered a course that resulted in deterioration of symptoms in some individuals. But all in all, it is less likely that the symptoms in general are caused by the vaccine, considered the fact that the group of women with assumed adverse reactions were overrepresented even before the vaccine was given. According to our results, there may be other factors than the vaccine itself that can explain the women’s symptoms”, says Kåre Mølbak.

Since the collection of data to this study ended, more than 800 women have reported assumed serious adverse reactions to the HPV vaccine. To this date, no scientific study has been able to document that the assumed adverse reactions are caused by the vaccine. Several studies document a decrease in the occurrence of cell changes and precancerous changes to cervix cancer as a result of the vaccination programme.

Read the scientific article in PLOS ONE:
Pre-vaccination care-seeking in females reporting severe adverse reactions to HPV vaccine. A registry based case-control study


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