Cervarix, a vaccine made to prevent the transmission of the human papillomavirus (HPV), reduced the rate of cervical cancer among women by 87 percent, revealed a study by scientists at Kings College London and published in the scientific journal The Lancet.
HPV is the most common viral infection of the reproductive tract. WHO states that most sexually active women and men will be infected at some point in their lives and some may be repeatedly infected. HPV is sexually transmitted but penetrative sex is not required for transmission, skin-to-skin genital contact is another well-recognized mode of transmission.
There are many types of HPV and while many do not cause problems, a small proportion of infections with certain types of the virus can persist and progress to cervical cancer. Cervical cancer is by far the most common HPV-related disease. Nearly all cases of cervical cancer can be attributable to HPV infection.
Cervical cancer is the fourth leading cause of cancer deaths among women worldwide. A study by Weiqing Ruan estimated that there were 570,000 new cases and 311,000 deaths (particularly middle-aged women) from cervical cancer globally in 2018.
Ruan’s study found that distribution of cervical cancer differs across the world, with than 85 percent of deaths occurring in developing regions. “Over 90 percent of the highest incidence rates of cervical cancer occur in sub-Saharan Africa. The drastic changes in epidemiological patterns of cervical cancer, over recent decades have been attributed to the effectiveness of the Papanicolaou test in improving detection of the human papilloma virus (HPV),” says the study.
In Mexico, according to Globocan data, during 2018 there were more than 7,800 new cases of cervical cancer and over 4,100 deaths. This disease represented the first cause of death in women between 25 and 34 years of age in 2018 and the second in those between 35 and 64 years old after breast cancer, according to the Ministry of Health. In 2018, INCan provided care for 370 cases but the number rose to 375 in 2019.
Early detection and vaccination have been the two most encouraged measures to reduce mortality. Mexico’s policies to enhance detection and promote vaccination have helped reduce its mortality significantly. For example, between 1980 and 2016, deaths from cervical cancer in women over 15 years of age decreased by 54 percent thanks to higher detection rates.
Since 2012, Mexico has included the HPV vaccine in the national vaccination scheme, which currently consists of the application of two doses to girls in the fifth year of primary school or 11 years of age.
To study the effectiveness of the Cervarix vaccine, scientists at the Kings College London used data from a total of 13.7 million-years of follow ups of women under 20. They observed that the vaccine reduced cervical cancer by 34 percent among girls between 16 and 18 years, 62 percent among girls aged 14–16 years and 87 percent among girls aged 12–13 years, in comparison to the unvaccinated.