Cervical cancer could be eliminated in many countries if enough vaccination coverage is achieved, based on the findings of an international study involving the University of Strathclyde.
The research, covering 65 studies of 60 million people in 14 nations, has found significant decreases in HPV (human papillomavirus) infections and precancerous cervical lesions over eight to nine years since vaccinations were introduced for girls.
The HPV vaccination was first licensed in 2007 and has since been taken up in around 100 countries and territories.
The study, published in The Lancet, provides strong evidence of HPV vaccination working to prevent cervical cancer, as both the cause - HPV infection - and precancerous cervical lesions are declining.
Since an earlier study by the international group, from 2015, the World Health Organization (WHO) has updated its position on HPV. It now recommends HPV vaccination of multiple age cohorts of girls aged from nine to 14 when the vaccine is introduced in a country, rather than vaccination of a single cohort.
Dr Kimberley Kavanagh, a Chancellor’s Fellow in Strathclyde’s Department of Mathematics and Statistics, was a partner in the study. She said: “These findings are hugely encouraging and are a strong indicator of the effectiveness of the HPV vaccination.
“They reflect the findings of our recent studies in Scotland, which have shown that the vaccine has had a vast and positive impact. It is playing a major role in the fight against cervical cancer.”
The analysis covers 23 articles on HPV infection, 29 on anogenital warts and 13 for CIN2+ lesions, one of the highest risk levels of abnormal cells associated with cervical cancer.
The researchers found that the two types of HPV that cause 70% of cervical cancers, HPV 16 and 18, were significantly reduced after vaccination. They report a decrease of 83% in girls aged 13-19 and of 66% in women aged 20-24 years after five to eight years of vaccination. An overall 54% reduction was seen in three other types of HPV, 31, 33 and 45 in girls aged 13-19 years.
There were also significant reductions in anogenital wart diagnoses. After five to eight years of vaccination, they found decreases of 67% in girls aged 15-19, 54% in women aged 20-24 and 31% in women aged 25-29 as well as reductions of 48% in boys aged 15-19 and 32% in men aged 20-24 years.
Five to nine years after vaccination CIN2+ decreased significantly. The team reports a 51% reduction in screened girls aged 15-19 years and a 31% reduction in screened women aged 20-24 years.
Dr Kavanagh also participated in studies of HPV vaccination in Scotland published in 2019. One found a reduction of nearly 90% in the virus since the vaccination was introduced for Scottish schoolgirls a decade ago.
Another found that 78% of people with head and neck cancers were men, while HPV was present in 60% of the cancers. This indicated that vaccinating schoolboys against the virus could dramatically reduce head and neck cancers in men.