There are 3,200 new cervical cancer cases reported each year in the UK, that’s 9 cases every day. This type of cancer has a 63% survival chance past 10 years without the disease. Cervical cancer is 100% preventable. A vaccination for certain strains has been available to girls between the ages of 12 to 18 in the UK for nearly 10 years. Australia has had such a successful vaccination programme, they have effectively eradicated the disease. So what is cervical cancer, why can we vaccinate against it, should boys also be given the vaccination, and how do we eradicate it?
Cervical cancer is the most common type of cancer for women under 35 in the UK. HPV (human papillomavirus) is a group of common viruses which cause cervical cancers amongst other things, such a warts. A staggering 99.7% of all cervical cancer cases are caused by a strain of HPV. The HPV is incredibly common and most of us will encounter it at one point or another during our lifetime without any trouble, our bodies defending us against invasion. However there are many different strains of HPV some of which are considered ‘high-risk’. These are more difficult to be rid of and are linked to various cancer types including cervical, vulval, and neck to name a few. When these high-risk strains enter the body they share their DNA with human cells, disrupting normal cell processes/function and potentially leading to the cells dividing uncontrollably. How can a vaccination defend us against cancer?
High-risk HPV can lead to abnormal tissue growth alongside other alterations to the structure of the cervix, hence the formation of cancerous tumours. HPV is a virus and viruses can be kept at bay with vaccinations. It is thought that 15% of all cancers are linked to various viruses. The HPV vaccine is one of the first to target a cancer causing virus. The vaccine contains virus-like particles (VLPs) which present HPV surface proteins, as shown in the image. These proteins prompt our body to fire up an immune response which in turn produces antibodies. Antibodies are stored in the body (a kind of memory storage), so that the next time you come into contact with the virus your body knows how to defend against it, and triggers immune response. The vaccination in the UK targets four strains of HPV (i.e. 16, 18, 6 and 11), two of which (16 and 18) cause 70% of all cervical cancer cases. Strains 6 and 11 cause 90% of all genital wart cases (the most common STD in the UK), thus the vaccine protects against this also.
How can a vaccination lead to the eradication of a disease? To date, only one disease has been eradicated globally through vaccination: smallpox, saving ~5 million lives yearly. Unicef claim that globally 7 diseases in total are under control thanks to the use of successful vaccination programmes (i.e. smallpox, diphtheria, whooping cough, measles, neonatal tetanus, hepatitis B, polio). HPV derived cervical cancer has the potential to join this list in the developed world within the next few years. Australia is leading the way as in 2015 they had vaccinated ~79% of all 15 year old girls and even ~73% of all 15 year old boys too. As a result, the rate of HPV derived cancer in 18-24 year olds dropped from ~23% to just 1.1% from 2005-2015. Strange you may think, to vaccinate boys too, but this is important to truly eradicate the disease. HPV can be contracted through skin-on-skin contact, such as sexual intercourse and men can carry the virus. If both men and women are immunised then the chance of contracting the disease and developing cancer as a result, drops dramatically.
Currently, the standard for UK women is 12 smear tests during their lifetime. However, a new study undertaken at Queen Mary University College, London suggests that the protection acquired as a result of the vaccination could lower this to just 3 visits in a woman’s lifetime! Screening is of course still required as the HPV vaccine only protects against two strains of the cancer causing virus, albeit the most prevalent ones which are linked to cervical cancer. True eradication requires the disease to be non-existent worldwide and for now the vaccination is only widely available in the developed world. While we in privileged countries may see the effects of the HPV vaccination programme soon, with decreased rates of cervical cancer cases, lower instances of genital warts and fewer smear tests required, the developing world is yet to be fully exposed to this brilliant programme. When smallpox was effectively vaccinated against across the Globe, millions benefitted. Hopefully this will be the case for cervical cancer too.