[Science] Just one dose of the HPV vaccine may be enough to lower cancer rates – AI

Cervical cancer rates are in decline thanks to the HPV vaccineMatthew Busch for The Washington Post via Getty Images By Ruby Prosser ScullyA single dose of the human papillomavirus (HPV) vaccine seems to be almost as good as two or three injections for preventing cervical cancer. The finding may make reaching the World Health Organization’s goal of eliminating cervical cancer easier than initially thought. Many people catch HPV through sexual activity, but the body’s immune system can usually wipe it out within a year or two. But when HPV infections persist they can eventually cause cancer. The virus is responsible for more than 99 per cent of cervical cancers, as well as causing vaginal, vulval, anal and penile cancers, and genital warts. In 2007, Australia rolled out the world’s first national HPV program, providing girls in schools with three free shots of the vaccine each. The injection is now offered to boys too, and the vaccine – which has been improved to protect against nine strains of HPV – is now usually given in two doses. Advertisement To understand how different doses of the vaccine affect the risk of developing cervical cancer, Julia Brotherton at the VCS Foundation in Australia and her colleagues analysed cervical screening data from a quarter of a million Australian women who were eligible for the vaccination. Read more: HPV vaccine has significantly cut rates of cancer-causing infections During this period, sexually active women were encouraged to have a Pap smear every two years to screen for cellular changes on the cervix that might be a sign of cancer. Analysing registers of HPV vaccinations and cervical cancer cases, the team found that women who’d had three doses of the vaccine were 41 per cent less likely to have these cellular changes – known as pre-cancerous lesions – than unvaccinated women. Women who’d had one or two doses of the vaccine were 35 and 39 per cent less likely than unvaccinated women to have these lesions. This data suggests that even one dose of the vaccine can be enough to help lower the incidence of cervical cancer. Administering a one-dose vaccination campaign would be cheaper and easier to administer than a multi-dose program. The finding could be particularly useful in developing nations, as low-income countries have the highest burden of cervical cancer but the least access to vaccines. Journal reference: Papillomavirus Research, DOI: 10.1016/j.pvr.2019.100177 More on these topics: infections cancer vaccines sexually transmitted infections