More Than HPV Vaccine Uptake Is Needed to Reduce the Burden of HPV-associated Cancers
HPV vaccination can prevent most cervical cancers
The burden of human papillomavirus (HPV)-associated cancers varies by racial and ethnic groups in the United States, with more frequency and sometimes more deadly consequences among Hispanics, blacks, and American Indian and Alaska Natives than among whites. Although vaccination is expected to decrease the cancer burden from HPV across all racial and ethnic groups, some disparities are expected to persist and widen if their causes are not addressed, including lack of access to screening, timely diagnoses, and treatment.1
"As expected, we found HPV vaccination would reduce the overall disease burden for all racial and ethnic groups. However, we also found that some racial and ethnic disparities may continue to exist," said Emily Burger, PhD, postdoctoral research fellow at the Harvard Chan School Center for Health Decision Science.
Currently, approximately 1 in 4 people in the United States are infected with HPV, or 80 million people. An estimated 14 million new infections occur each year. HPV infection may resolve on its own within 2 years; however, chronic HPV infection can result in various forms of cancer.
HPV vaccines have been licensed and recommended for boys and girls since 2006. The vaccines are expected to reduce the incidence of 6 HPV-associated cancers, including cervical, anal, and oropharyngeal cancers. Recently, a 9-valent HPV vaccine was licensed and is expected to protect against additional HPV types that can cause cancer.
Up to 3 of 4 HPV-associated cancers can potentially be prevented by HPV vaccination.
However, uptake has been slow. Less than half of girls, and even fewer boys, age 13 to 17 years have completed the recommended series of 3 doses, according to recent data from the Centers for Disease Control and Prevention (CDC). In addition, the number of young people who complete the vaccine series differs by racial and ethnic group. This is in contrast to the adolescent Tdap vaccine (protecting against tetanus, diphtheria, and whooping cough), which is consistently received by 85% or more of adolescents across all racial and ethnic groups.
This study used mathematical modeling to simulate the impact of alternative HPV vaccine coverage scenarios on 6 HPV-associated cancers for different racial/ethnic groups. The researchers accounted for current cancer incidence rates and survival probabilities; the proportion of cancers due to HPV; and current HPV vaccination rates by age, sex, race, and ethnicity.
The modeling found that relative disparities may persist and even increase in some cases. If high uptake of the newer 9-valent vaccine is assumed, the lifetime risk of dying of an HPV-associated cancer for males decreased by approximately 60%, but the relative disparity increased from 3.0 to 3.9. The greater disparity is partly because a smaller proportion of oropharyngeal cancers in black males are associated with HPV infection than in white males, so vaccination would not have as much of an impact on the overall cancer burden for that group.
"Our findings show that vaccination can lead to a dramatic decrease in HPV-associated cancer in all racial and ethnic groups, but HPV vaccination alone will not eliminate existing HPV-associated cancer disparities. Efforts to improve HPV vaccination uptake in the U.S. must also be accompanied by efforts to minimize differences in access to screening for cervical cancer and access to timely diagnoses and treatment for all HPV-associated cancers," said Jane Kim, PhD, associate professor of health decision science at Harvard Chan, and senior author of the study.
1. Burger EA, Lee K, Saraiya M, et al. Racial and ethnic disparities in human papillomavirus-associated cancer burden with first-generation and second-generation human papillomavirus vaccines [published online ahead of print April 28, 2016]. Cancer. doi:10.1002/cncr.30007.