1. Facts about POTS and Gardasil

17 April 2015

It has neither been confirmed nor denied that POTS may be an adverse reaction to Gardasil

Postural Orthostatic Tachycardia Syndrome (POTS) is characterised in a heavy increase in the heart rate after sitting or standing up and in a labile blood pressure when standing up. The typical symptoms include dizziness, severe exhaustion and fainting. POTS can be diagnosed by using tilt table tests. The syndrome can occur after rapid growth in the teens, infectious diseases, severe trauma or virus infections.

POTS occurs in both men and women, but is most frequent in women aged from 15 to 50 years. The exact frequency is not known, but figures from the National Patient Registry show that 96 patients diagnosed with POTS were hospitalised in the period from 2006 to 2012. POTS also occurs in persons who have not been vaccinated with Gardasil.

Total number of reports

Globally, a total of 66 reports have been submitted about POTS as a suspected adverse reaction after the HPV vaccine (figure as at 30 September 2014). The majority of the reports were submitted in Denmark and the USA. At the end of the third quarter of 2014, we had registered a total of 33 Danish reports where the POTS diagnosis was reported as a possible adverse reaction to the HPV vaccine. About 165 million doses of the HPV vaccine have been distributed worldwide.

Assessment of the relationship between POTS and Gardasil

At the beginning of December 2014, the EU's Pharmacovigilance Risk Assessment Committee (PRAC) ended its routine review of the safety of Gardasil. PRAC concluded that at present it is not possible to confirm or deny whether there is a causal link between vaccination with Gardasil and the occurrence of POTS. Due to several circumstances, it is difficult to assess whether POTS is a possible adverse reaction to the HPV vaccine. The reason is that POTS is a relatively new diagnosis with varying symptoms. To this should be added an occurrence of POTS in the population, an unknown frequency and undisclosed causal mechanisms. Consequently, POTS must be monitored closely in connection with future reviews of the safety of Gardasil, and special measures have been launched in the form of a new questionnaire that will ensure follow-up on adverse reaction reports of symptoms suggestive of POTS.

PRAC’s overall assessment of the HPV vaccine in December 2014 is that the benefits of preventing the development of cervical cancer still outweigh the risks associated with vaccination and the risk of adverse reactions.

The Syncope Centre at Frederiksberg Hospital and the Danish Health Authority agree on these assessments.

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