Vaccinated against Cancer?
This academic year, thousands of 13 year old girls will be offered the new HPV vaccine Gardasil to defend against Cervical Cancer. Superior to its predecessor Cervarix which only protects against two strains of HPV, Gardasil protects against four. This means that it not only provides defence against Cervical Cancer, which currently affects approximately 3000 women in the UK every year, but also against genital warts.
The HPV vaccine scheme was launched in 2008, providing three jabs throughout a six month period to girls aged 13-18. Currently vaccination uptake in England is 84.1%, which is likely to reduce rates of cervical cancer dramatically in years to come.
But what confuses people is the link between viruses and cancer. How does a vaccine protect against a disease that we’re told grows from within us? And what is HPV?
HPV (Human Papilloma Virus) is a virus easily spread through sexual contact. There are about 120 different strains, but many of these are completely harmless. Strains 16 and 18 are the high-risk strains, and are able to invade human skin cells. Once inside the cell, the viral genes are transported to the nucleus, where human genes are stored. This allows the viral genes to be replicated, reproducing somewhere between 10 and 200 copies of the virus per human cell, and also producing a number of viral proteins which contribute to cancer. The two most harmful of these proteins, E6 and E7, modify the natural life-cycle of a cell so that it is constantly stuck in divide-mode. This constant state of division leads to growths, and left untreated can eventually lead to cancer.
The HPV vaccine aims to stop all of this. Between the two of them, HPV 16 and HPV 18 cause 75% of cervical cancers, so with both Cervarix and Gardasil acting against these strains, we are likely to see a massive reduction in coming years. And now with Gardasil protecting against HPV6 and HPV11 (which together cause 90% of genital warts) this infection should also hopefully disappear.
And it’s not just girls who should be getting the jabs either. A massive reduction in the spread of HPV and also in male genital warts could be tackled if this vaccination was also offered to boys.