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| HUMAN PAPILLOMAVIRUS |
Disease
Human papillomavirus (HPV) is a family of viruses that are very common all over the world. Although most HPV infections cause no symptoms and are selflimited, persistent genital HPV infection can cause cervical cancer in women (as well as other types of anogenital cancers, head and neck cancers, and genital warts in both men and women). Oncogenic HPV serotypes 16 and 18 account for 70% cases of cervical cancer. They have also been implicated in the causation of vulvar, vaginal, penile and oropharyngeal cancers. Nononcogenic HPV serotypes 6 and 11 are responsible for more than 90% of anogenital warts.
Occurrence
HPV is common worldwide and estimated to cause more than half a million new cancers every year and 274 000 deaths (2002 estimate), most of which affect women in developing countries.
Risk for travellers
Travel itself does not increase the risk of exposure. Transmission of HPV is most commonly through sexual activity: condoms may not offer complete protection. Travellers are advised to check with the relevant health authorities regarding national recommendations and the availability of HPV vaccination in their country.
Vaccine
Human papilloma virus vaccine is available as a bivalent vaccine or a quadrivalent vaccine. Both vaccines are licensed for use in females for the prevention of the cervical cancer and other pre-cancerous lesions caused by human papilloma virus types 16 and 18. In addition quadrivalent vaccine is licensed for use in females for the prevention of genital warts and pre-cancerous lesions caused by human papilloma virus types 6, 11, 16 and 18. The two vaccines are not interchangeable and one vaccine product should be used for an entire course.
The vaccine is intended for use primarily in girls and young women for prevention of diseases caused by the HPV genotypes included in the vaccine. Human papilloma virus vaccine will be most effective if given before sexual activity starts and is recommended for administration to girls and young women before in the age of 9-45 years. The first dose is given to females aged 12 to 13 years, the second and the third doses are given 1-2 and 6 months after the first dose; all 3 doses should be given within a 12 month period. If the course is interrupted, it should be resumed but not repeated, allowing the appropriate interval between the remaining doses. The duration of protection has not been established, but current studies suggest that protection is maintained for at least 6 years after completion of the primary course. It will, however, take time to be able to measure duration of protection in terms of clinical efficacy and thus a booster dose is not recommended at present, based on follow up data of five to six years duration only.
As the vaccines do not protect against all strains of human papilloma virus cervical screening should continue. |
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