To date, we know over 150 types of human papillomavirus. 13 of these which are now considered high-risk are proven to be capable of triggering the formation of malignant cervical cancer. 2/3 of all these tumors are caused by type 16 and type 18 strains. It is also clear that it is not the only type of cancer that is caused by an HPV infection. Viral DNA has been identified in a number of other malignant tumors of the external genitalia (vulva), the anus, vagina but also some tumors found in the oral cavity and the neck. However, these are not the only negative effects of a HPV infection on human health. Papillomavirus infections, aside from being responsible for malignant tumors also cause non-malignant but very unpleasant complications such as anogenital warts (known as condylomata). The reasons for seeking protection from these viruses are crystal clear. Vaccination currently offer a very good method of doing just that.
Currently, three types of vaccination are available. They differ primarily in the amount of viral strains that they protect against. A bivalent vaccine protects against high-risk type 16 and 18 strains, tetravalent vaccine adds protection against low-risk type 6 and 11 strains. These types account for approximately 90% of all cases of anogenital warts. The last and newest vaccine type includes, among the 4 above mentioned strains, protection against further 5 high-risk strains. In practice, this translates to protection against 4/5 of all strains responsible for causing malignant cervical cancer.
Vaccination is ideally carried out prior to becoming sexual active. At this point it is the most effective. If vaccination is administered before turning 15, sufficient protection is provided with 2 doses instead of the regular 3. Vaccination makes sense and is recommended for all individuals who are already sexually active. However, in such cases it is not as effective and certainly cannot be expected to treat an existing infection. In this case, vaccination protects children against those types of viruses that the person has not yet been infected with. Vaccination is also recommended for women who are preparing for or have undergone treatment of the cervix as a result of having identified pre-cancerous changes associated with an HPV infection. On the other hand, pregnant women as well as those with weakened immune systems should not undergo vaccination. The actual vaccination itself with regards to any serious side-effects and reactions is considered very safe.
Supported by numerous scientific studies, it is now possible to confirm with certainty that vaccination against HPV significantly decreases the risk of malignant cervical cancer, tumors in the anogenital region and very likely also some tumors found in the oral cavity as well as the neck. Unfortunately, it does not offer 100% protection. Approximately 1/5 of all cases of malignant cervical cancer cases are caused by the remaining HPV strains which the vaccines currently do not protect against. This is why it is essential to undergo regular preventive gynecological examinations.