Human papillomavirus (HPV) is a group of viruses which are extremely common around the globe. Within this group of viruses, there are around 14 that we know of that are cancer-causing. Cervical cancer ranks as the fourth most frequent cancer in women and according to figures from 2017, cervical cancer accounts for 1% of all deaths for females living in the UK. The HPV vaccination program, therefore, presented a huge potential step in the fight against cervical cancer, and it has been successfully rolled out across the UK and US. Initially in the UK, it was only offered to girls, but in 2018, the Joint Committee on Vaccination and Immunisation (JCVI), which advises UK health departments on immunisation, decided the HPV vaccine should also be offered to boys.
For Cervical Cancer Awareness Week, we’re asking where we are now with HPV. And to help us answer this question, we have enlisted the help of our Faculty Member, Gregory Zimet, whose article recommendations can be found on Faculty Opinions.
Gregory received his PhD in Clinical Psychology from Duke University in 1985. He is currently a Professor of Pediatrics & Clinical Psychology at Indiana University School of Medicine in Indianapolis, Indiana, US. His current research program focuses largely, but not exclusively, on determinants of vaccine hesitancy and confidence, with a particular interest in HPV vaccination.
Gregory conducted his first study on the HPV vaccine acceptability before the vaccine was first licensed in the US. Since then, he has carried out dozens of studies examining HPV vaccine attitudes, determinants of vaccine uptake, the impact of public health policy on HPV vaccination, and evaluation of behavioral interventions to improve HPV vaccination rates. He has also studied cervical cancer screening from a behavioral or social science perspective. He tells us: “In 2012 I founded and currently serve as co-director of the Indiana University-Purdue University, Indianapolis (IUPUI) Center for HPV Research, which has over 30 members from multiple schools who engage in a range of research activities, from basic laboratory science to public health policy research.”
When we asked Gregory for his summary of HPV based on his extensive knowledge, this is what he told us: “HPV stands for human papillomavirus. There are many different types of HPV, a subset of which cause genital warts or a number of cancers, including cervical, vaginal, vulvar, anal, penile, and oropharyngeal cancers.” He continued, “HPV is most often transmitted via skin-to-skin contact, often sexual contact. When certain types of HPV persist as an infection (types 16 and 18, in particular), the infection can lead to pre-cancers and cancers.”
”Over the next several years we will begin to see sharp declines in HPV-related cancers. This decline will be most apparent in countries with the most effective HPV vaccination strategies, such as Australia, Malaysia, and the UK.
The roll-out of the HPV vaccine was a huge breakthrough in public health, but the policies which surround the vaccine have been challenged and adapted since it’s initial launch. Gregory tells us, “The HPV vaccine policy has undergone many changes since HPV vaccine was first licensed by the Food and Drug Administration in 2006.” He explains, “It was first approved as a 3-dose regimen only for females, aged 9-26 years and routinely recommended for all females 11-26 years of age. In 2009, the quadrivalent HPV vaccine was approved for males, but did not carry with it a routine recommendation.”
In 2011, it was announced that the recommendation had been changed to include routine vaccinations for males aged 11-21 years, with 22-26 years only routinely recommended for certain risk groups. Following this change, additional amendments followed, including the development of the 9-valent vaccine, the removal from the US market of the bivalent vaccine, and the switch from 3 to 2 doses as long as the first dose is administered prior to age 15 years.
Gregory elaborates, “The current recommendation is for routine administration of the 9-valent vaccine to all males and females aged 11-26 years, but vaccination can start as young as 9 years. The primary focus is to vaccinate those who are 11-12 years of age. There is a shared clinical decision-making recommendation (not routine) for adult males and females aged 27-45 years.”
”Of ongoing concern is the fact that many lower-income countries, which often have the highest rates of cervical cancer, do not have adequate access to HPV vaccines. As a result, there will be an increasing disparity in HPV-cancer incidence between higher-income and lower-income countries.
Typically it can take years for HPV-related cancers to develop, and so the incidence of these cancers remains mostly unchanged in the US. However, Gregory tells us that over the next several years we will begin to see sharp declines in HPV-related cancers. He explains, “This decline will be most apparent in countries with the most effective HPV vaccination strategies, such as Australia, Malaysia, and the UK”. He continued, “Of ongoing concern is the fact that many lower-income countries, which often have the highest rates of cervical cancer, do not have adequate access to HPV vaccines. As a result, there will be an increasing disparity in HPV-cancer incidence between higher-income and lower-income countries.”
Research has been conducted to assess the value of the HPV vaccine in lower-income countries and in the past 10 years we have seen remarkable progress in the global scale‐up of HPV vaccinations, however, the prevalence of the vaccine remains low in comparison to high-income countries.
More recent research conducted on the HPV vaccine has found that the vaccine may actually provide men with “herd immunity” against oral HPV infections. We asked Gregory for his thoughts on this: “In this study the researchers found that prevalence of vaccine-type HPV in the oral cavity of unvaccinated men decreased by nearly 40%. At the same time, nonvaccine-type oral HPV prevalence remained the same.” He explained, “This set of findings suggests that, due to vaccination, the amount of vaccine-type HPV in circulation has decreased, leading to a decrease even among unvaccinated men, which probably reflects a degree of herd immunity or herd protection.”
”New research findings suggest that, due to vaccination, the amount of vaccine-type HPV in circulation has decreased, leading to a decrease even among unvaccinated men, which probably reflects a degree of herd immunity or herd protection.
Finally, we asked Gregory about his most recent Faculty Opinions recommendation, which highlighted research that explored the last strategy for re-dissemination of HPV vaccination in Japan. He told us why he chose it: “Japan’s experience with HPV vaccination has been a source of tremendous consternation among HPV researchers, clinicians, and public health experts. Due to unfounded concerns about vaccine safety, the government in Japan suspended their recommendation for HPV vaccine in 2013.” He explains, “As a result, the vaccination coverage dropped precipitously and has remained quite low. The research I recommended on Faculty Opinions showed that local municipalities could improve HPV vaccination coverage, despite the national government’s suspension of recommendation, by sending out an informational leaflet on HPV vaccination as prevention of cervical cancer. The vaccination coverage after the campaign was still low (just over 10%), but this represented a significant and substantial increase from the pre-intervention level of 1.4%”