In wealthy countries that have vaccination programs, the Human Papillomavirus (HPV) vaccine has significantly reduced the rate of HPV-related infections.
Researchers at the Université Laval in Quebec who looked at 66 million young men and women found that the problems caused by the virus have significantly decreased across a number of wealthy countries.
The meta-analysis of 65 studies found that, depending on age and diagnosis, rates of HPV infection and genital warts had fallen by between 31% and 83%. The prevalence of precancerous lesions caused by HPV has also decreased since the introduction of the vaccine.
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Use of the HPV vaccine is now becoming even more widespread in some countries, which will probably mean a significant drop in cervical cancer rates since this type of cancer is nearly always caused by HPV infection. More than 90% of anal cancers, 70% of oral, neck and throat cancers and more than 60% of penile cancers are all caused by HPV.
Cervical cancer can take as long as 20 years to develop, so the vaccine, which was first introduced in 2006, has not been available long enough for researchers to reliably tell whether HPV-related cancer incidence has fallen. However, the significant decline in infection rates is expected to result in similar falls in the associated cancer incidence.
A number of reviews have shown that the HPV vaccine is one of the safest vaccines available. Receiving the jab can be painful, but the only side effects that tend to be reported are soreness and redness at the injection site and sometimes fainting among adolescents.
The most effective way to combat cervical cancer has so far been screening, but this only flags up tissue that could become cancerous, whereas the vaccine stops the infections that cause this abnormal tissue to develop in the first place.
Since it is not currently possible to screen for HPV-related cancers, the vaccine remains the only way to prevent them from developing.
The vaccine is so effective that it even partially protects unvaccinated people on account of it reducing the prevalence of HPV among the wider population of sexually active people.
As reported in The Lancet, the current study found that rates of the two HPV strains that the vaccine protects against had fallen by 83% among teenage girls and by 66% among young women aged between 22 and 24 years, up to eight years after vaccination.
The incidence of anogenital warts also fell by nearly 70% among teenage girls and by 54% among women aged under 25. Among unvaccinated males, the authors also observed a 48% drop in teenagers and a 32% drop in men aged 20 to 24 years.
The fact that the incidence among unvaccinated men is also dropping shows just how effective the vaccination program is. The incidence of grade 2 cervical neoplasia also fell by half among girls aged between 15 and 19 years and by 31% among women aged 20 to 24 years.
The HPV vaccine needs to be made available across Africa
The vaccine is mainly only administered to women, but in countries where young men were also vaccinated, the protective effects were even greater. However, the vaccine is generally only available in high-income countries, with lower income countries not having yet adopted widespread use among men and women.
Study author Marc Brisson says: “Vaccinating girls in these countries would have the greatest impact on the worldwide burden of HPV-related cancers.”
In Africa, many women are dying from cervical cancer, even though doctors know what causes it and how to prevent it. At least 68,000 cases of cervical cancer arise every year and 46,000 women die as a result of the disease.
In a guest column for AllAfrica, director of Policy and Advocacy for Nigeria Health Watch, Ifeanyi Nsofor, writes that too many women on the African continent die from sexually transmitted diseases where we know the cause and how to prevent it: “This is unconscionable and should not continue.”
Nsofor says there are three approaches that could ensure the success of HPV vaccination in wealthy countries is replicated in Africa and that they must involve multiple stakeholders including health ministries, governments, schools and pharmaceutical companies.
Firstly, many people in Africa, particularly those in rural areas, do not have access to healthcare. A combination of poverty, lack of healthcare access and out-of-pocket payments mean women who need the vaccine are not given it.
If HPV vaccination is going to be made available in Africa, universal health coverage is needed so that people can access healthcare without suffering from financial hardship, writes Nsofor.
Secondly, the cost of a single vaccine is $39 in public facilities and $71 in private facilities, which is not affordable for people living in extreme poverty.
National health insurance schemes and Health Maintenance Organisations (HMOs) in Africa should add HPV vaccination and cervical cancer screening services as components of health plans that can be purchased by families. In the long run, it is cheaper to provide these preventative services than to treat cervical cancer.”
Thirdly, the age at which the vaccine is supposed to be given is an age where the majority of eligible girls are supposed to be in high school. Targeting them would require a combined effort from education ministries, school owners and principals, parents and the girls themselves.
‘It is possible to prevent cervical cancer’ through vaccination
Nsofor says school outreach should begin with communicating the risks of cervical cancer to these stakeholders; they should be educated about its prevalence, causes, prevention, treatment, and prognosis: “Supplemental vaccination campaigns conducted in schools with the permission of school authorities and the consent of parents is a quick way of immunizing all who are eligible.”
Nsofor also thinks cervical cancer screening should be part of the overall approach to disease prevention and that since infected boys can develop cancers of the penis, anus, and pharynx, it is essential that they are also vaccinated to ensure that men who have sex with men are also protected.
The United Kingdom has shown that it is possible to prevent cervical cancer by deploying nationwide HPV vaccination. It is inexcusable to allow women (and men) to die from preventable diseases. African governments must show leadership by replicating the UK programme across the continent.”
Drolet, M., et al. (2019). Population-level impact and herd effects following the introduction of human papillomavirus vaccination programmes: updated systematic review and meta-analysis. The Lancet. DOI: https://doi.org/10.1016/S0140-6736(19)30298-3.