Human papillomavirus and HPV vaccines: a review

Abstract

Cervical cancer, the most common cancer affecting women in developing countries, is caused by persistent infection with "high-risk" genotypes of human papillomaviruses (HPV). The most common oncogenic HPV genotypes are 16 and 18, causing approximately 70% of all cervical cancers. Types 6 and 11 do not contribute to the incidence of high-grade dysplasias (precancerous lesions) or cervical cancer, but do cause laryngeal papillomas and most genital warts. HPV is highly transmissible, with peak incidence soon after the onset of sexual activity.A quadrivalent (types 6, 11, 16 and 18) HPV vaccine has recently been licensed in several countries following the determination that it has an acceptable benefit/risk profile. In large phase III trials, the vaccine prevented 100% of moderate and severe precancerous cervical lesions associated with types 16 or 18 among women with no previous infection with these types. A bivalent (types 16 and 18) vaccine has also undergone extensive evaluation and been licensed in at least one country. Both vaccines are prepared from non-infectious, DNA-free virus-like particles produced by recombinant technology and combined with an adjuvant. With three doses administered, they induce high levels of serum antibodies in virtually all vaccinated individuals. In women who have no evidence of past or current infection with the HPV genotypes in the vaccine, both vaccines show > 90% protection against persistent HPV infection for up to 5 years after vaccination, which is the longest reported follow-up so far. Vaccinating at an age before females are exposed to HPV would have the greatest impact. Since HPV vaccines do not eliminate the risk of cervical cancer, cervical screening will still be required to minimize cancer incidence. Tiered pricing for HPV vaccines, innovative financing mechanisms and multidisciplinary partnerships will be essential in order for the vaccines to reach populations in greatest need.

Awareness of Turkish Female Adolescents and Young Women about HPV and their Attitudes Towards HPV Vaccination

“…HPV vaccines are prepared from empty protein shells called virus-like particles produced by recombinant technology (Cutts et al, 2007). They do not contain any live biological product or DNA, so they are non-infectious.…”

Making the case for cervical cancer prevention: what about equity?

“…52,53 Since the vaccines are not effective against HPV once a person has been infected with it, and acquisition of HPV infection can occur relatively quickly after sexual debut, 54,55 it is widely accepted that providing young adolescent girls with the vaccine before the onset of sexual activity is the most cost-effective strategy. 56,57 Unlike screening, though, which has a proven track record of reducing cervical cancer rates when high quality services are made widely available, questions about the overall effectiveness of HPV vaccination programmes need time to be resolved.…”

EpidEmiological FEaturEs oF papillomatosis causEd by thE human papillomavirus in WomEn attEnding thE basic hEalthcarE clinic in nova iguaçu county, statE oF rio dE JanEiro

“…This finding corroborates the findings of an epidemiological study on HPV infection in women in the United States, which found a low prevalence of vaccinated women (18) . Several studies demonstrated the efficacy of the HPV vaccine in the prophylaxis and reduction of the morbidity and mortality that is associated with anogenital HPV infection (19,20) . Conversely, the authors of an editorial that was published in the Brazilian Journal of Gynecology and Obstetrics (Revista Brasileira de Gineco Obstetrícia) in 2007 stated that if a program of massive HPV vaccination was developed, the epidemiological effects may not be evident for several years, and there would be no significant effect on cervical cancer screening (21) .…”