Scientists and government officials are today at loggerheads about how well the HPV vaccine works.
A new study says past research has over-estimated how effective the jab is because it’s too soon to record actual cervical cancer rates.
But a statement from Public Health England says real-world data shows HPV infections have dropped from 15 per cent to fewer than two per cent in 10 years.
HPV causes almost all cases of cervical cancer and many experts believe that by stopping it spreading they will be able to all but wipe out the disease in England.
Separate statistics released today, however, show the number of women being diagnosed with cervical cancer has risen sharply in the years since the jab was introduced.
The HPV vaccine is now given to all girls and boys in school Year 8, and protects primarily against four strains of the disease which are known to be linked to cervical cancer and genital warts (stock image)
It is too soon for the vaccine to have stopped most cases of actual cancer, which may take decades to develop so is more common among older people.
In unfortunate cases young women are diagnosed with the disease, but experts cannot expect to see cancer rates really come down until decades into the future.
‘With millions of young women protected by HPV vaccination, we expect to see big reductions in cervical cancer in years to come,’ said Public Health England’s Dr Vanessa Saliba.
‘And the introduction of the boys’ programme will accelerate this progress.’
PHE’s statistics show fewer than two per cent of 16 to 18-year-olds now have HPV strains 16 and 18, which are most responsible for cervical cancer.
And infections with HPV types 6 and 11, which cause genital warts, have halved since vaccination began in 2008.
When the vaccination programme began, around 15 per cent of sexually-active young women had types 16 or 18 while 10 per cent had 6 or 11.
The latest PHE statistics show that 83.9 per cent of Year 9 girls had received both doses in 2018/19.
REVIEW OF PAST STUDIES CLAIMS HPV VACCINE IS ‘NEAR PERFECT’
The HPV vaccine is almost 100 per cent effective even in the real world, according to scientists.
Scientists at King’s College London analaysed data from studies involving some 60million people over eight years to work out the true effectiveness of the jab.
They found that the vaccine appears to be 99.8 per cent effective at preventing HPV five years after it is given.
‘Our analysis finds that the near perfect efficacy of HPV vaccination in … trials is realised in real-world settings,’ said Professor Peter Sasieni, who did the research.
‘These results imply that the impact of HPV vaccination on preventing cervical cancer could be even greater than estimated previously.’
The vaccine was developed to prevent HPV types 6, 11, 16 and 18 from spreading.
Types 16 and 18 cause more than 70 per cent of cervical cancer cases in the UK, while types 6 and 11 cause 90 per cent of of genital warts cases – the jab protects against both.
Professor Sasieni’s research used data from a review published last year which combined 65 other studies from 14 countries.
It aimed to check the real-world effectiveness of the jabs, which may not have turned out to be as effective as they were in laboratory tests.
And it found the jab was 92 per cent effective within four years of it being given; 99.8 per cent effective after five years; and 97.6 per cent effective overall.
This was when the researchers took into account how well the vaccine in worked in people who received it, and the proportion of people who did receive it.
The research was published in the medical journal The Lancet.
Eleven million doses of the vaccine have been given to young women in England, meaning over 80 per cent of women aged 15 to 24 are protected.
The Government body hopes cancer rates will turn out to be lower when the women who were in the first waves of vaccinations reach ages at which they could be expected to start developing cancer.
But scientists at Newcastle University and Queen Mary University in London have re-analysed 12 past studies and found they may have oversold the jab’s cancer-preventing abilities.
The team said trials of the vaccine have considered only early-stage cervical changes and measured them too frequently.
In fact, many of the abnormalities they picked up on would never have gone on to become cancerous and would have resolved themselves.
‘We found insufficient data to clearly conclude that HPV vaccine prevents the higher-grade abnormal cell changes that can eventually develop into cervical cancer,’ said Dr Clarie Rees, from Queen Mary University.
‘Abnormal cell changes are likely to have been overdiagnosed in the trials because cervical [testing] was conducted at six to 12 months rather than at the normal screening interval of 36 months.
‘This, too, means that the trials may have overestimated the efficacy of the vaccine, again because some of the lesions would have regressed spontaneously.’
Dr Rees and her colleagues added that the women recruited in trials of the vaccinations were older than real-world targets and had ‘limited relevance’.
Despite disagreements, experts in all camps said women must go for cervical screening appointments, which undeniably reduce cancer rates.
Professor Jonathan Ball, from the University of Nottingham, was involved in neither sets of research but commented: ‘The authors in their provocative piece do raise some important points highlighting that HPV vaccination isn’t the absolute panacea for cervical cancer prevention, for example in cases where HPV infection isn’t the cause.
‘If anything, the take home message to me, is that we still need to understand more fully the long-term benefits and efficacy of HPV vaccination and ensure that adequate cancer screening is available to all.’
Chief executive of the charity Jo’s Cervical Cancer Trust, Robert Music, said: ‘It is fantastic to see the effectiveness of the HPV vaccine among young women.
‘Hopefully this will lead to significant reductions in cervical cancer diagnoses.
‘Ensuring uptake remains high must remain a priority and this new data will hopefully encourage such action.
‘We must not forget that the vaccine does not prevent against all HPV types and there is still a risk of cervical cancer among those who have had the vaccine.
‘Cervical screening remains the best way to further reduce this risk.’
Dr Rees and her colleagues published their research in the Journal of the Royal Society of Medicine.