HPV vaccine has major impact on reducing infections, cancer, study finds
HPV infections were reduced by 66 to 83 per cent after five to eight years of vaccination.
Vaccination against the virus that causes almost all cervical cancer is having a major impact on stopping infections and should significantly reduce cases of the disease within a decade, researchers said on Wednesday.
Presenting results of an international analysis covering 60 million people in high-income countries, scientists from Britain and Canada said they found "strong evidence" that vaccination against the human papillomavirus (HPV) works "to prevent cervical cancer in real-world settings."
"We're seeing everything that we'd want to see. We're seeing reductions in the key HPV infections that cause most cervical disease, and we're seeing reductions in cervical disease," said David Mesher, principal scientist at Public Health England, who worked on the research team.
Marc Brisson, a specialist in infectious disease health economics at Laval University who co-led the study, said the results suggested "we should be seeing substantial reductions in cervical cancer in the next 10 years."
HPV vaccines were first licensed in 2007 and have since been adopted in at least 100 countries worldwide. Britain's GSK makes an HPV vaccine called Cervarix, which targets two strains of the virus, while Merck makes a rival shot, Gardasil, which targets nine strains.
In countries with HPV immunization programs, the vaccines are usually offered to girls before they become sexually active to protect against cervical and other HPV-related cancers.
Infections reduced by 66 to 83 per cent
Brisson's team analyzed data on 60 million people over eight years from 65 separate studies conducted in 14 countries and pooled it to assess the vaccines' impact.
They found that the two HPV types that cause 70 per cent of cervical cancers — known as HPV 16 and HPV 18 — were significantly reduced after vaccination, with an 83 per cent decline in infections in girls aged 13 to 19 and 66 per cent drop in women aged 20 to 24 after five to eight years of vaccination.
Figures released in February by the World Health Organization's International Agency for Research on Cancer showed an estimated 570,000 new cases of cervical cancer were diagnosed worldwide in 2018, making it the fourth most common cancer in women globally.
Each year, more than 310,000 women die from cervical cancer, the vast majority of them in poorer countries where HPV immunization coverage is low or non-existent.
Brisson urged governments in the most-affected countries to take note: "Our results show the vaccines are working — so I hope in the upcoming years we will ...see rates of HPV vaccination increase in countries that need it most," he said.