The human papillomavirus is the most common sexually transmitted virus. There are more than 200 known papillomaviruses, of which the most serious group, cancer-causing viruses, comprise 14 subtypes.
The onset of cervical cancer can be prevented with the HPV vaccine, which suppresses the papillomaviruses that cause cancer. Sufficiently extensive vaccination of entire age groups will practically eradicate cervical cancer in just a few decades.
In Scotland, 85–90 of every 100 girls receive the HPV vaccine, already part of the country’s national immunisation programme since 2008.
“Scotland’s example is very encouraging, as premalignant conditions of cervical cancer are disappearing throughout the country. In the coming decades, Scotland’s vaccination coverage will result in the near-total eradication of the disease,” says Pekka Nieminen, docent at the University of Helsinki and a chief physician.
A high risk of transmission
In Finland, cervical cancer cases have, since the 1960s, decreased to one-fifth of the initial figures thanks to a national screening programme. However, this promising trend is shadowed by increasingly young people becoming at risk of contracting the disease.
Each year, approximately 170 women develop cervical cancer in Finland, one-third of whom die of the disease. New cases of cervical cancer are diagnosed increasingly often in young women of childbearing age.
Ever since the late 1990s, cervical cancer has become increasingly common among women under 40 years of age. These days, those suffering from the disease are most likely of childbearing age, whereas earlier it was a disease of older women. One explanation is the increasing number of HPV infections.
From November 2013 onwards, Finnish girls have been offered the HPV vaccine free of charge. The vaccination is part of the national vaccination programme. Extensive HPV vaccinations for girls carried out in time prevent approximately 80% of all cervical cancers. The ideal age of vaccination is 11–12 years.
According to Nieminen, who works at the Women’s Hospital of the Helsinki University Hospital, the risk of adolescents and young adults contracting HPV is extremely high. For a number of decades, the number of HPV infections has been steadily growing all the way to the early 2010s. As much as every third woman over 20 years of age is infected with HPV.
A small share of the infections worsen: without appropriate treatment, they may, over time, evolve into cervical cancer.
Benefits should be advertised
The HPV vaccine should be administered before sexual activity begins, as it will only protect against HPV infections if administered in time.
The Communicable Diseases Act stipulates that municipalities have the right to implement the HVP vaccination of girls in a manner they see fit. Eleven- and twelve-year-old girls are vaccinated under school health services at either the school or health centre.
However, a certain degree of hesitation has hindered the implementation of HPV vaccinations in Finland. False information on vaccinations and vaccines is spreading among both parents and adolescents, with wild discussion threads on social media engendering and promoting collective fear.
“Social media has enormous power. Laypeople consider themselves just as knowledgeable as individuals whose profession it is to investigate the efficacy and safety of vaccines,” Nieminen points out.
Often, children and young people are influenced by their more strong-minded friends.
“School classes have thought leaders. If they make a racket about the potential adverse effects of the vaccination or its uselessness, many others may also start thinking along those lines,” says Hanna Nohynek, chief physician at the National Institute for Health and Welfare.
It would be beneficial to talk about the efficacy of the HPV vaccination with children and adolescents in a matter of fact way.
Nohynek believes that the increasing evidence pointing to links between swine flu vaccinations and narcolepsy cases has also contributed to the difficulties faced by the HPV vaccination programme.
There are also other factors at play. Certain families may think that the vaccine encourages young people to become sexually active too early. Parents need not be asked for permission to have the vaccination, which has already been part of the national vaccination programme for over five years, but they can forbid its administration by contacting the school. However, school nurses can offer the vaccination to students once they are older and the decision becomes entirely their own.
Pekka Nieminen points out that to children, being vaccinated is not a particularly big deal. There is so much else going on in their lives.
“A couple of days later, a girl of 11 or 12 years of age may not even remember getting a vaccination at school, let alone consider it to have any relation to embarking on their sexual life,” Nieminen says.
The National Institute for Welfare and Health also recommends including a HPV vaccination for boys in the national vaccination programme.
The article was originally published in Finnish in the Y/02/19 issue of Yliopisto-lehti.
What is HPV?
The acronym HPV stands for ‘human papillomavirus’, a common viral infection contracted by eight out of ten people during their lifetime.
There are approximately 200 known papillomaviruses, most of which cause skin inflammations. These symptoms can also occur in the genital area.
Part of genital HPV infections develop into cancers of the cervix, vulva, vagina, penis or anus, in addition to which a portion of cancers in the head and neck area are caused by HPV infections.
Cancer-causing strains of HPV include, in particular, HPV 16 and 18, while types 6 and 11 also cause genital warts.
No causal relation to autoimmune diseases
Some time ago, a national television channel in Denmark presented a documentary claiming that the HPV vaccine causes autoimmune diseases and rare neurological syndromes. Autoimmune diseases include rheumatoid arthritis, thyroiditis and type 1 diabetes. In Denmark, the subsequent uproar caused a temporary dip in the vaccination coverage from 80% to 30%.
In Finland, the National Institute for Health and Welfare conducted an extensive study as part of vaccine safety monitoring. The results were unambiguous: Girls who were vaccinated between ages 11 and 15 had no heightened risk of developing the autoimmune diseases investigated in the study. Vaccinated girls were compared with girls of the same age group who had not received the vaccine.
The study concerned girls who were given the HPV vaccination between 2013 and 2015 under the national vaccination programme.
Saved by herd immunity
Vaccination coverage and herd immunity are two key concepts related to vaccination. Vaccination coverage denotes the share of people from a certain age or risk group who have been vaccinated.
Once a sufficient share of the population or a population group has been vaccinated, the safety of the unvaccinated population also improves. In other words, immunity on the population level also indirectly protects those who have not been vaccinated. This is known as herd immunity.
The vaccination coverage required to achieve herd immunity varies by communicable disease. For HPV infections, a vaccination coverage of approximately 80% is needed to generate herd immunity.
Of those in the high-risk group, 80 out of every 100 individuals must receive the HPV vaccine, after which the remaining 20 non-immunised individuals are protected by herd immunity, as the number of papillomaviruses among the entire high-risk population falls to a sufficiently low level.
In Finland, the HPV vaccination coverage of girls has varied annually between 67% and 74%.
“With the current vaccination coverage of about 70%, achieved by vaccinating girls only, papillomaviruses are on the decline, but at a sluggish rate. This coverage will not rid us of HPV 16, the type that most often causes cancer,” notes Tuija Leino, chief physician at the National Institute for Health and Welfare.