Q - Is a vaccine for cervical cancer in development?
A - Two major designs of vaccine are being researched. Preventive vaccines are intended to protect against acquiring infection with HR-HPV.
They are based on artificial 'virus-like particles' (VLPs) made of virus coat proteins by biotechnology. These stimulate protective antibodies. Recently, a VLP vaccine against HPV 16 has been shown to prevent very effectively HPV 16 infection and related precancer longer than one to two years in uninfected young women.
The second type aims to treat established precancers and cancers. Such vaccines have used sections of cancer-causing 'viral oncogenes' to attempt to stimulate cellular immune rejection of lesions. These vaccines, so far, show limited clinical effectiveness.
There is a real probability that preventive vaccination could ultimately replace cervical screening and protect women in developing countries where screening is unaffordable. But there is a need to develop vaccines for the range of HR-HPV types and determine their long-term effectiveness against high-grade precancer and invasive cervical cancer.
Such research takes time and investment. Vaccines for preventive programmes should be available in five to 10 years, and then the process of replacing screening with vaccination can begin.
David Jenkins is consultant histopathologist at Nottingham University Hospital
Careful research has shown that close to 100 per cent of cervical cancer is caused by human papillomaviruses that infect anogenital mucosae. Two types of high-risk human papillomaviruses (HR-HPV), HPV 16 and 18, together account for over 70 per cent of cervical cancer as well as other anogenital and tonsillar cancers. Vaccines for cervical cancer are aimed at HR-HPV, currently HPV 16 and 18.
To change completely could take 30-40 years.