Human Papillomavirus (HPV)

Genital human papillomavirus (HPV) infection is one of the most common sexually transmitted infections (STIs), affecting both men and women1. There are over 100 types of HPV, and 13 of these are cancer-causing (also known as high risk type). HPV is largely transmitted through sexual contact, and around 75% of sexually active people will have HPV at some point2. Most people infected with HPV have no symptoms and their body spontaneously clears the infection. However, if HPV persists, it may infect the cervix area which can cause abnormal pre-cancerous cells to develop. If undetected these cells may progress to invasive cervical cancer3.

Vaccinations can protect against some types of HPV which cause cancer. However, there are limitations with the vaccinations, and they do not eliminate the need for regular HPV and/or cervical screening throughout life.

On this page you can learn about how HPV is contracted and develops, the HPV vaccination and controversies, and how you can manage your risk of HPV effectively.

How do you contract HPV?

Anyone who is sexually active can get HPV, even if you have had sex with only one person. You can also develop symptoms years after you have sex with someone who is infected which makes it hard to know when you first became infected. Using latex condoms while you have sex can lower your chances of getting HPV, but HPV can infect areas that are not covered by a condom. Therefore, condoms may not give full protection against HPV.

HPV and the risk of developing cervical cancer

Women with a persistent infection with high-risk HPV types are at risk of cervical cancer. This is because in some instances a persistent infection with a high-risk type of HPV can progress to invasive cancer if not detected and treated1. This usually takes 10 years or more.

Persistent HPV infection is the underlying cause of all cervical cancer. However, among women with persistent HPV infection, additional factors may contribute to the development of cervical cancer. These include smoking, taking hormonal contraceptives, having a suppressed immune system, and the presence of other sexually transmitted infections.

In Aotearoa New Zealand the most important risk factor for developing cervical cancer is not having cervical smear tests. Regular cervical smears can reduce the risk of developing cancer by about 90 percent.

 

HPV vaccinations

Vaccination can protect against infection with the HPV types covered by the vaccine, provided the woman is not already infected with those types of HPV. However, vaccination does not protect against all HPV types and a woman may still become infected with another HPV type not included in the vaccine. HPV vaccines are not a treatment for HPV infections. There are currently two licenced HPV vaccinations in New Zealand – Gardasil® and Cervarix®

 

Gardasil®

The Gardasil® vaccine is publicly funded and is free for men and women aged 9 to 26, including non-residents under the age of 18. The vaccine is given in three doses, usually an initial dose with follow-ups two months and six months afterwards. Gardasil® is said to be effective in protecting against infection from;

     ➜ types 16 and 18 (high-risk), which are associated with 70% of cervical cancers
     ➜ types 6 and 11 (low-risk) which cause up to 90% of genital warts but do not cause cervical cancer.

The World Health Organisation (WHO) state that Gardasil® significantly decreases the incidence of anogenital warts and reduces high-grade cervical abnormalities1. However, persistent HPV infections take a long time to develop into invasive cancer, which means ongoing studies are needed and definitive conclusions about the vaccine’s impact long-term cannot yet be drawn.

In terms of safety, the WHO Global Advisory Committee for Vaccine Safety (GACVS) has regularly reviewed the evidence on the safety of HPV vaccines, and reports continue to be positive regarding safety. However, adverse reactions following the administration of Gardasil® have been reported. If you think you have experienced an adverse reaction make sure you report this to your doctor or nurse. Alternatively you can report directly to the Centre for Adverse Reactions Monitoring (CARM) at the New Zealand Pharmacovigilance Centre.

 

Cervarix®

 The other HPV vaccine licensed for use in Aotearoa New Zealand is Cervarix®, which is effective in protecting against infection with HPV types 16 and 18. Cervarix® is not publicly funded in New Zealand.

HPV vaccine controversy

There has been some controversy following the introduction of PHV vaccines. Some of the opposition stems from moral concerns, arguing that vaccinating young women against STIs could increase sexual activity prior to marriage. More importantly is the risk that fewer young women will have smear tests, mistakenly thinking they are protected by the vaccine.  If this was the case, there is the danger that immunisation could lead to an increase in cervical cancer cases.

Women’s Health Action, while welcoming the opportunity to reduce the incidence of cervical cancer, also advise caution. The potential impact of the vaccination programme on cervical screening uptake must be evaluated along with any unanswered questions about its safety and long-term effectiveness. Additionally, there is a lack of understanding about HPV and its relationship to cervical cancer, which means we need more education to ensure young women and their families can make informed decisions about cervical cancer prevention2.

 

Preventing cervical cancer: An integrated approach

HPV vaccines provide a promising new tool in helping to address HPV-related diseases, including cervical cancer. However, the WHO recommends that the prevention of cervical cancer and other HPV diseases will be best achieved through a coordinated and comprehensive strategy which includes;

     ➜ Education on the risk behaviours which increase the chance of acquiring HPV infection (safer sex)
     ➜ Information to women about screening, diagnosis and treatment of precancerous lesions and cancer
     ➜ Access to quality screening and treatment services.
     ➜ Linking the introduction of the HPV vaccine to other programmes targeting young people (e.g. through adolescent health services)2.

 

What can I do to reduce my risk?

Ask your doctor about HPV vaccinations and decide if they are right for you, use condoms while having sex, and most importantly have regular cervical screenings.

 

Useful links

 Human papillomavirus » detailed information about HPV

 HPV vaccine » Ministry of Health’s information about vaccinations

 The New Zealand HPV Project » educational organisation focused on the prevention and treatment of HPV

 Time to Screen » information on cervical screening, managed by the National Screening Unit

 

References

 

1World Health Organisation, ‘Human papillomavirus vaccines: WHO position paper, October 2014’, Weekly epidemiological record No. 43, 2014, 89, 465–492. Retrieved from: http://www.who.int/

2Parker, Christy. “One for the girls? “Cervical cancer prevention and the introduction of the HPV vaccine in Aotearoa New Zealand.” Women’s Studies Journal 24 (2010): 25-39.3.

3New Zealand HPV Project. (2019). Some questions and answers about HPV and genital warts. Auckland, New Zealand: Author.