One of the proposed participatory budgeting projects in Kraków was introducing free HPV vaccination. But did we really know what we voted for or against? In this edition of 1Question, Dr hab. Krzysztof Pyrć from the JU Faculty of Biochemistry, Biophysics and Biotechnology talks about HPV – the Human Papillomavirus.
1Question is a series of articles by the University Marketing science communication unit, in which specialists and experts from various fields briefly discuss interesting issues related to the world, civilisation, culture, biology, history, and many more.
The first mentions of warts date back to the times of ancient Rome and Greece, but their relation to viruses was not proved until the early 20th century. Today, we know that papillomaviruses (from Latin papilla – wart) comprise a very large group of pathogens which cause mostly non-dangerous skin lesions, such as warts, in humans and animals. However, during the course of research, the scientists have discovered that these viruses may cause cancer. Amongst over a hundred human papillomaviruses, thirteen have been linked to a higher risk of cancer. The fact that infection by viruses from this group is very common, and that cancer is one of the greatest challenges which our medicine has yet to overcome, makes papillomaviruses a subject of great interest for scientists and a serious threat to public health.
For instance, cervical cancer – one of the most frequent malignant forms of cancer in women – is almost always related to the papillomavirus. According to estimates, there are half a million new cases annually, while about 250 thousand patients die of this condition.
Turning virus into cancer
There are many factors responsible for the development of cancer in the human organism, but two of them seem particularly important. Research shows that high-risk strains (HPV16 and HPV18) produce substances which may conduce the development of cancer. One of them is the E6 viral protein, which modulates the activity of some signalling pathways in cells. The E6 viral protein destroys the human p53 protein, which is responsible for detecting "dangerous" cells. Reducing the effectiveness of p53 may thus be compared with disabling an alarm system.
The second detrimental substance responsible for raising the risk of cancer is the E7 protein. The protein causes unrestricted growth and accelerates the rate at which cells reproduce. Such intervention in the basic cell mechanisms may lead to disorders, including genetic disorders.
Treatment and prevention
The most important measure in preventing infectious diseases is severing the chain of transmission. The most dangerous strains of HPV are transmitted sexually. According to research, condoms are not an effective way of protection against infection. Researchers are currently trying to create an agent which could be used in gels or lubricants to stop the virus from transmitting.
Without a question, the most effective and safe method of protecting against diseases is vaccination. In accordance with World Health Organisation recommendations, vaccines should be used mainly by girls aged 9–13. This is due to the fact that the vaccine is the most effective before they first risk being exposed to the virus, i.e. before they become sexually active. In some countries, vaccination of boys is also advised, since it further reduces the possibility of disease transmission.
In the European Union, there are two registered HPV vaccines: Gardasil (Sanofi Pasteur MSD) / Silgard (Merck Sharp and Dohme) and Cervarix (GlaxoSmithKline Biologicals). They are both subunit vaccines, which means they do not contain dead or live viruses, but only fragments with no genetic material, so they cannot cause disease. Cervarix is a two-valent vaccine (it contains fragments of HPV16 and HPV18), while Gardasil/Silgard contains fragments of four viruses – HPV6, HPV11, HPV16 and HPV18.
Both vaccines are safe to use and protect from infection, provided that the vaccination took place before exposure. Clinical research has shown that the vaccine protected patients from being infected in 90% of cases.
The vaccination programme was introduced in most EU countries – regrettably, not yet in all of them. The exceptions are: Poland, Cyprus, Estonia, Finland, Hungary, Lithuania, Malta and Slovakia. Additionally, activities of anti-vaccination movements muddy the waters and downplay the importance of vaccines.
So, if we are infected, should we panic? Of course not! Regular medical examinations, such as cytology, will help in rapid identification of risk and its elimination. The period of time between being infected and developing cancer lasts for many years!
It is worth to mention that papillomavirus infection is usually not dangerous and is fought off by the organism. In these cases, treatment is not necessary. However, if a medical checkup determines that there is a risk of cancer, the affected tissue may be removed, frozen or cauterised. If the patient is infected in the genital area, pharmacology is employed instead. However, no medication destroys the virus by itself – they only boost our immune system. Neither of the methods destroys the virus entirely, so recurrence is highly likely.
Original text: www.nauka.uj.edu.pl
