Gardasil effective in women already exposed to HPV infection
By Lilian Anekwe
Pressure is building on the Department of Health to widen the school-based HPV immunisation programme, after new research found substantial benefits for vaccinating young women even when they had been exposed to the virus.
Young sexually active women showed comparable protection from cervical cancer after vaccination with Gardasil as women who had never been exposed to HPV infection.
The research will strengthen calls for the programme to be extended to women in their 20s and will also fuel the debate over whether Gardasil is a better vaccine than Cervarix, which the DH chose for use on the NHS.
The decision to vaccinate girls aged 12-17 was made after initial modelling suggested it was most effective in girls who had never been exposed to the sexually transmitted HPV virus.
But the new research found a similar reduction in cervical lesions across women aged up to 26 – regardless of prior HPV exposure.
The study cohort included more than 17,000 women aged 16 to 26 who had either never had sex, who had but were unexposed to HPV, or who had been exposed to types 6, 11, 16 or 18.
There were 30 lesions per 10,000 women in the group of HPV-unexposed women, compared with 40 per 10,000 in the HPV-exposed group.
The number of cervical lesions prevented was similar in the three populations, as was the estimated reduction in colposcopies and abnormal smears.
Study leader Dr Joseph Monsonsego, head of colposcopy at the Institue Fournier in Paris, concluded: ‘Our data suggest we could expect similar disease reduction in the years immediately following vaccination.'
Dr Paula Briggs, a GP and sexual health specialist in Liverpool, said: ‘I do not think there is much doubt immunisation has potential benefits to patients outside the UK programme.
‘Even if there has been prior exposure to one of the virus types in the vaccine, this would be more likely to result in latent rather than persistent infection, so there would be potential benefit in immunisation.'
Professor Peter Stern, head of immunology at the Paterson Institute of Cancer Research said: ‘Where a women has been exposed to HPV there is still value in preventing infection of other types and no down side to boosting natural immunity.'Key study findings
• Number of prevented cases of precancerous cervical lesions (CIN 2/3 or adenocarcimona in situ) – 30 per 10,000 women in HPV-unexposed women, 40 per 10,000 in the HPV-exposed women
• Estimated reduction in colposcopies –130 per 10,000 women in both groups
• Reduction in abnormal cervical smears – 130 per 10,000 in the HPV-unexposed women, 150 per 10,000 in HPV-exposed women
Source: Monsonego et al. International Congress on Anti Cancer Treatment, February 2009, Paris, France, abstract.
Debate on HPV vaccination programme reopened after research finds Gardisil effective on sexually active young women