Separating facts from fiction on HPV vaccine

Numerous reviews (based to date on studies that have included several million people) have repeatedly shown the HPV vaccine to be safe.

Cervical cancer is diagnosed in about 300 women every year in Ireland and is responsible for approximately 90 deaths annually. Importantly, it also ranks as the second most common cause of death due to cancer in women aged 25-39. There has been an increasing level of awareness of cervical cancer in recent years with an almost 80% uptake in the national cervical screening programme. Furthermore, vaccination against HPV associated cervical cancer has been offered in Ireland since 2010 to all girls under 15 years of age.

In 95% of cases, cervical cancer is preceded by pre-malignant changes in the neck of the womb (cervix) caused by several strains of HPV (Human Papilloma Virus). The HPV represents a group of about 200 viruses that can infect several body sites and gives rise to warts on the skin or genital areas. 

The virus is so widespread that the most people will acquire HPV during their lifetime, though in the overwhelming majority of cases no treatment will be required. HPV infection is most commonly acquired in those in their late teens and 20’s and is contracted by either sexual activity or skin contact with an infected person.

However, HPV can cause abnormal growth in the cervix (CIN or Cervical Intra-epithelial Neoplasia) that can in a proportion of cases progress into cervical cancer. The smear test screening programme identifies 6,500 women annually who have pre-cancerous CIN lesions that require treatment. It can also pick up cervical cancer at an early stage when a cure is possible.


The vaccine ‘Gardasil’ designed against the common HPV strains (16, 18) that account for 90% of cervical precancerous lesions was approved in 2006. Gardasil is proven to be up to 99% effective at preventing precancerous growths due to HPV 16 and 18 and genital warts due to HPV 6 &11. Indeed, in the UK, Canada and Australia there has been a dramatic decline in precancerous lesions in association with Gardasil use. Overall, it is estimated that Gardasil prevents about 70% of cervical cancers caused by HPV.

In fact, Gardasil is recommended in over 25 European countries and since 2007 has been used globally in over 100 million people. In Ireland, 220,000 have been vaccinated and it is currently offered to girls in their first year of secondary school (when the vaccine provides better protection). 

Vaccination requires two doses given at least six months apart or three doses in those aged over 15. Well reported side effects include pain or swelling around the injection site (10%), mild fever, nausea (1%) and rare reactions in the skin (0.1%) and wheeziness (0.01%).

However, controversy has followed its use with regard to anecdotal reports of a wide spectrum of other adverse effects ranging from chronic fatigue, depression, seizures, headaches and allergic reactions. Indeed, uptake of the vaccine in Ireland has dropped from 87% to 50% on the back of such concerns. To date, about 1,000 adverse reactions have been reported to the Irish Health Products Regulatory Authority (HPRA), but many of these related to the administration of the vaccine itself. In addition, they are recorded with no medical adjudication as to other possible causes and so therefore have to be viewed cautiously.


Numerous reviews (based to date on studies that have included several million people) have repeatedly shown the vaccine to be safe, with no evidence to link it to any serious adverse affects. Indeed, the WHO advisory committee on vaccine safety in its 2017 report concluded that Gardasil was extremely safe, with in particular no association with conditions such as chronic fatigue or pain syndromes (which occur at the same rate in the general population). 

In Ireland, a parents support group called REGRET (Reactions of Gardasil Resulting in Extreme Trauma) has brought to the fore many alleged side effects of the vaccine. In reality, these reports represent less than 0.5% of all those who have completed the full vaccination course. 

On the back of a lower vaccine uptake, the HSE has begun a new information campaign in advance of the launch of its vaccination programme for the 2017/2018 schools year. A ‘HPV Vaccination Alliance’, formed recently in Ireland from a coalition of representatives of more than 30 organisations, also strongly supports vaccination.

In summary, while there are anecdotal reports of several adverse affects attributed to the vaccine, these are not borne out in studies involving several million who have been vaccinated. Gardasil is proven to be effective and the evidence for its use is very compelling.


*Dr Kevin McCarroll is a Consultant Physician in Geriatric Medicine, St James’s Hospital, Dublin.