Analysis, published in the Journal of the Royal Society of Medicine, reports that the HPV vaccine may be less effective than previously thought.
Dr Gillian Knight, Associate Dean, School of Engineering & Applied Science, Aston University.
“This was an interesting study as it compared current research methodology, demonstrating a lack of consistency in how these clinical investigations were conducted. This study has presented this lack of a standardized approach in a rather negative manner and as such there needs to be some caution over the interpretation of the studies key findings.
“As more research is being conducted into the impact of HPV vaccination on HPV prevalence within the community, there is clear evidence that the HPV vaccines are effective in reducing HPV infection. Although, the study does raise some good points in relation to using a more consistent approach to this type of research as this would enable a greater understanding of the impact of HPV vaccination at a global level and enable more cross referencing between different clinical studies.
“It needs to be noted that the duration of HPV vaccination to continue to protect against HPV after initial vaccination, and its effectiveness against cross protection, is still being globally investigated. As such, the observation by this research team that a more standardized approach to epidemiology studies may be of use to inform future clinical study design and enable more research to be conducted into the impact of HPV vaccination on all HPV related diseases and not just cervical cancer.”
Prof Margaret Stanley, Emeritus Professor of Epithelial Biology and Research Visitor in the Department of Pathology, University of Cambridge, said:
“The problem with this study is that the analysis of clinical trials from many years ago has been superseded by evidence of the real-world effectiveness of the HPV vaccine.
“In the 15 years since these randomly controlled trials were done, countries such as Australia, Demark, Sweden, Scotland, England, etc have implemented vaccinating girls (usually aged 12 – 14 years old) and have managed to achieve more than 70% vaccination coverage and good screening programs. These countries have reported big falls in cervical pre-cancers in the vaccinated groups. Scotland is probably the best example of this happening in the UK and last year Palmer et al1 reported that girls vaccinated in Scotland aged 13-14 in 2008/9 who subsequently underwent cervical smear testing aged 20 has 86% reduction in CIN3 (severely abnormal cells found on the surface of the cervix) compared to those who were unvaccinated. Such a dramatic reduction is hard to attribute to statistical chatter. Similar results have also been seen in Denmark. CIN3 is a precancerous change which is an obligate precursor to cervical cancer and it is the change which the cervical smear test is looking for so they can be removed if found. Scotland also has a national vaccine register so it is easy to compare the occurrence of cervical disease between those who have been vaccinated and those who have not. In light of this evidence, it is difficult to hold doubts about the effectiveness of the HPV vaccine.
“The study by Rees et al argues that CIN3 at the age of 20 is different to CIN3 in women of older ages. However, the peak incidence of cervical cancer in the UK is in woman aged 25-302 so reducing CIN3 in woman aged 20 years old will likely be effective in reducing cervical cancer, but only time will tell.”
Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:
“We should guard about over-interpreting their findings. Undoubtedly the current HPV vaccines are effective at preventing infection with the types of virus known to cause cervical and other cancers. But 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.”
‘Will HPV vaccination prevent cervical cancer?’ by Rees et al. was published in the Journal of the Royal Society of Medicine at 00:05 UK time on Wednesday 22nd January.
Dr Gillian Knight: “No conflicts of interest.”
Prof Margaret Stanley: “I consult for both GSK and Merck Sharp & Dohme Limited”
Prof Jonathan Ball: “No CoIs”