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.


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.


Source: Sally Robertson, B.Sc.
Review: Kate Anderton, B.Sc. (Editor)
Picture: CNK02 | Shutterstock


