Do HPV vaccines work?

Editorial Board

Editorial Board

June 7th, 2017

Editorial Board

‘Cases of human papilloma virus, which causes cervical cancer, have fallen 90% in Scotland’

The HPV vaccine is now used in dozens of countries, including the US, Canada, Australia and most of Western Europe. It is given to girls around 12-13 years of age to prevent the spread of human papilloma viruses which can lead to cancers of the cervix (and several other less common cancers) as well as genital warts. Some countries also provide the vaccine to boys.

It has been in use in some countries for a decade and is beginning to show real results.

So, does the vaccine work?

The short answer is ‘yes’. The latest addition to the growing volume of evidence supporting the vaccine comes from Scotland. HPV vaccines have been recommended in Scotland since 2008 and update is very high.

A new research paper by experts at Health Protection Scotland shows that HPV vaccination could ultimately protect against eight out of 10 cervical cancers. The study finds a current 90% drop in reported cases of HPV disease since the vaccine was introduced and a decrease in cervical cancers is expected within the next few years.

This is even better than expected: it had been thought that the vaccine would protect against viruses responsible for between seven and eight out of 10 infections.

“The two HPV types we were vaccinating against – HPV 16 and HPV 18 – cause about 70% to 80% of cervical cancers within Scotland but the vaccine has exceeded our expectations because it appears to have knocked out another three high-risk HPV types which cause about 10% of cervical cancer,” Dr Kevin Pollock at Health Protection Scotland told BBC Scotland.

The vaccines protect against the virus types that cause 90% of cervical cancer cases. They are very effective, with efficacy against most of these strains of about 95%, so overall they can be expected to prevent about eight out of ten cases in fully vaccinated women, with the risk in other women also being reduced through population immunity.

Dr Pollock said the fall in cases of HPV disease will lead to a significant drop in future cervical cancer cases and the experts hope to see a decrease in new cancer diagnoses within a year.

Body of evidence

The Scottish data adds to a growing body of evidence showing how effective HPV vaccines are in stopping the virus from spreading.

Research published last year in the journal Pediatrics showed a dramatic drop in human papilloma virus (HPV) presence among teenage girls and young women in the US since the introduction of HPV vaccination.

Earlier research from Australia has already shown a 61% drop in the number of cases of genital warts in boys, thanks to HPV vaccination.

Cases of cervical cancer before the age of 20 are rare – the typical (median) age of diagnosis is 49 – so the real impact on cancer cases will take time. But all the signs are promising.