Friday February 1 2013
The HPV vaccine protects against several cancers
Boys as well as girls should receive the HPV vaccine, say experts, it was reported by the BBC and others today. The experts, gathered together by the Throat Cancer Foundation, say the change is needed to prevent a rise in throat and other cancers among men.
Since September 2008, girls in the UK aged 12-13 years have been offered the HPV vaccination. HPV stands for human papilloma virus – a group of viruses that are spread through direct contact and infect the moist mucous membranes in the body, such as the nose, mouth, throat, rectum, vagina and cervix.
While successful in combating cancers in women, there is a growing pressure across the world to extend HPV programmes to boys. In Australia a programme has already been introduced and some experts believe it should be introduced in the UK. They argue that it would combat the rise in HPV-related head and neck cancers in men and, in particular, would protect gay men who derive no direct protection from the vaccination programme in women.
Although throat cancer is rare, under the current HPV vaccination programme girls are receiving additional protection against viruses that may cause it, while boys are not. This has caused debate, with experts from the Throat Cancer Foundation quoted in the media as saying that this issue is a “ticking time bomb” and is discriminatory against boys
Professor Simon Rogers, consultant maxillofacial surgeon at the University Hospital Aintree, is quoted by the BBC as saying that if current trends continue, cases of throat cancer will exceed cervical cancer cases by the year 2020.
The Throat Cancer Foundation wishes to extend the vaccination programme to boys to give a “gender neutral vaccination”. But, on the strength of the current evidence, the Department of Health currently has no plans to extend the vaccination programme.
What is HPV and what diseases can it cause?
Human papilloma viruses (HPV) are viruses that infect the moist mucous membranes in the body – such as the nose, mouth, throat, rectum, vagina and cervix. The viruses can be spread through direct skin-to-skin contact or sexual contact.
There are more than 100 different strains (types) of HPV. These are numbered and can cause different types of disease or infection. HPV viruses are very common, and many people will be infected with one form or another at some point in their lives. Many people will be infected with an HPV virus that causes no symptoms or only mild symptoms – such as veruccas or warts on the hands and feet. These usually go away without treatment.
But some strains of HPV are more dangerous and can cause changes to cells, which can trigger the onset of cancer.
The cancers that different HPV viruses have been associated with include:
Using a condom during any sexual contact is a good way to protect against HPV strains that infect the genitals. However, as condoms do not cover the whole genital area they cannot give complete protection.
How does the current NHS HPV vaccination programme work?
The NHS HPV vaccination programme was introduced in September 2008. The original vaccine (Cervarix) gave protection against HPV strains 16 and 18, which are known to account for around 70% of cervical cancer cases. Since 2012 the vaccine Gardasil has been used. This protects against four HPV strains – 16 and 18 and also 6 and 11, which cause around 90% of genital warts.
Currently, girls aged 12-13 are routinely vaccinated. There was also an initial ‘catch-up’ campaign to cover girls under 18. The vaccinations are given as part of a three-dose schedule over 12 months, and involve giving a viral protein in a structure called a virus-like particle (VLP). Live HPV virus is not given, and no serious side effects have been associated with the vaccination programme.
The primary aim of the NHS HPV vaccination programme is to protect against cervical cancer, by providing immunity against the two HPV strains that cause most cases of cervical cancer. However, while strains 6 and 11, which are included in the vaccination, are the main cause of genital warts in both girls and boys, only girls are currently receiving this protection.
All four strains in the vaccine have been associated with cancers in men. In particular, strains 6 and 11 may cause warty growths to develop on the larynx (vocal cords) or in the oesophagus (food pipe). These growths can undergo cancerous changes and cause throat cancer.
The NHS does not provide HPV vaccination to males. Boys and men who want the vaccination have to pay for it privately.
What evidence is there that vaccinating boys would reduce disease?
The Throat Cancer Foundation gives statistics that 35% of throat cancers are caused by HPV, with oesophageal cancer most associated with the virus. The charity quotes Professor Margaret Stanley, Director of Research at the University of Cambridge, who says that: “If recent incidence trends continue, the annual number of HPV-positive oropharyngeal cancers is expected to surpass the annual number of cervical cancers by the year 2020”.
An editorial published in the journal Nature last year points out that HPV causes 5% of all human cancers. It also highlights the fact that genital warts (caused by HPV) are the commonest sexually transmitted viral disease. While genital warts are not especially serious they can be upsetting as well as both expensive and time-consuming to treat. Despite this, only females are currently given protection against HPV through the NHS vaccination programme.
Professor Stanley provides figures of the “sex-neutral burden” of HPV-related warts and cancers. HPV types 6, 11, 16 and 18 have been related to the following conditions:
- head and neck cancers – 12,700 new cases in males in Europe every year, and 2,530 in females
- genital warts – 325,700 new cases in males in Europe every year, and 289,000 in females
- anal cancer – 1,700 new cases in males in Europe every year, and 2,930 in females
- cervical cancer – 23,250 new cases in females in Europe every year
- vulva and vaginal cancer – 3,850 new cases in females in Europe every year
- penile cancer – 1,090 new cases in males in Europe every year
Professor Stanley references, among other sources, an article published last year in the journal BioMed Central (see the further reading section). This article was written by Hartwig et al. of Sanofi Pasteur MSD, which is a company specialising in vaccines. (This potential conflict of interest was stated clearly in the article.)
The study aimed to look into the burden of HPV-related disease in men in Europe, including genital warts and cancers of the anus, penis and head and neck cancers. The researchers used Eurostat population data, cancer incidence rates published by the International Agency for Research on Cancer, and prevalence estimates of HPV viruses 6, 11, 16 and 18.
This modelling study reported that, every year, 72,694 new cancer cases develop in European men at HPV-related sites on the body (for example, the penis, anus, head and neck). They estimate that almost a quarter of these cancers (17,403) could be directly attributable to HPV, with 15,497 of them specifically caused by HPV 16 or 18.
In addition, it was estimated that between 286,682 and 325,722 new cases of genital warts attributable to HPV 6 or 11 occur annually in European men. The study concluded that around 30% of all new cases of cancer caused by HPV 16 or 18 in Europe occur in men.
Meanwhile, almost all non-cancerous HPV-related conditions in men (for example genital warts) are caused by HPV strains 6 and 11. The authors say that the HPV vaccine could potentially prevent these conditions.
In her editorial, Professor Stanley continues that HPV vaccine trials have shown that the vaccine can protect against HPV infection and related anal and genital disease in men, but what is less clear is whether vaccination of men is cost effective.
She discusses that, in theory, the ‘herd immunity’ of all vaccinated females would give protection to men who only have sex with women, but that would not protect men who have sex with men.
She also points out that limiting the distribution of the vaccine to men who have sex with men to save money would be problematic since, to be most effective, the vaccine should be given during the early teenage years, when sexual preferences may not be established.
Overall, Professor Stanley concludes that: “it is not ethical, fair or socially responsible to have a public-health policy that forces men to rely on herd immunity, which won’t be reached for decades”. She says: “Let’s start vaccinating men now.”
What does the Throat Cancer Foundation say?
The Throat Cancer Foundation wishes to extend the vaccination programme to include boys, making it a so-called “gender neutral vaccination”. The Foundation disputes current policy, which relies on “herd immunity” – meaning that if 80% of the female population is vaccinated then this will give protection to men. Echoing Professor Stanley’s standpoint they raise issues about the discriminatory nature of this policy, including against men who have sex with men (MSM). This group, which has the highest burden of anal cancers, is unprotected by the current HPV vaccination programme.
The United States, Canada and Australia currently recommend vaccination for both girls and boys, and they believe that we should follow suit.
What is the response of the Department of Health to the charity’s call?
A Department of Health spokesperson, quoted in the BBC News coverage of the story, said: “There are currently no plans to extend HPV vaccination to males, based on an assessment of available scientific evidence.
"Vaccination of boys was not recommended by the Joint Committee on Vaccination and Immunisation because once 80% coverage among girls has been achieved, there is little benefit in vaccinating boys to prevent cervical cancer in girls.
"Eighty per cent coverage for the full course of three doses of the vaccine was achieved in the first year of the HPV vaccination programme in 2008-9, and has since exceeded that level."
Can I pay to have my son vaccinated privately?
Yes. The Gardasil vaccine is available from most private vaccination clinics. The cost of the complete course of the vaccine (three doses) can range from around £300 to £400 depending on the provider.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.