Improved Vaccine Protects Against 9 Cancer-Causing Strains of HPV
Researchers from the Moffitt Cancer Center find that the newest HPV vaccine protects against 9 cancer-causing strains of the virus.
A study conducted by researchers from the Moffitt Cancer Center finds that the newest human papilloma virus (HPV) vaccine, 9vHPV, also known as Gardasil 9, is “highly effective” in the prevention of nine different strains of cervical cancer-causing HPV.
HPV is an incredibly common virus; in fact, the Centers for Disease Control and Prevention (CDC) estimate that about 1 in 4 individuals are infected with this virus in the United States alone. The virus is transmitted through skin-to-skin contact, most commonly through sexual intercourse. According to the CDC, most HPV cases go away on their own; however, sometimes individuals go on to develop genital warts, and infection with some strains can result in cancer.
Although there are hundreds of strains of HPV, only 13 are associated with cancer development, according to a press release on the study. It is estimated that HPV 16 and HPV 18 in particular are responsible for a staggering 70% of all cervical cancers.
According to the American Cancer Society, an estimated 12,820 cases of invasive cervical cancer will be diagnosed this year in the United States alone, and 4,210 of them will die from it. Cervical cancer is “the second most common cause of cancer-related death worldwide,” according to the press release. The majority of these deaths, 80%, happen in developing nations.
Although the development of HPV vaccines has worked to cut down the number of infections, as well as deaths, an improved vaccine works to expand that umbrella of protection. The results of the study were published in The Lancet.
There are currently two HPV vaccines on the market that have been designed to protect against HPV types 16 and 18: Cervarix and Gardasil. In addition to protecting against these types of HPV, Gardasil also offers protection against the development of genital warts that are typically caused by HPV types 6 and 11.
Armed with this information, scientists sought to improve the HPV vaccine so that it will protect against more of the types of HPV that are associated with cervical cancer. Results have shown that, not only does Gardasil 9 protect against HPV types 16, 18, 6, and 11; it also offers protection against 5 more types of cancer-causing HPV: Types 31, 33, 45, 52, and 58.
“Based on epidemiological studies, the [Gardasil 9] could prevent approximately 90% of cervical cancer, 90% of HPV-related vulvar and vaginal cancer, 70% to 85% of high-grade cervical disease in females, and approximately 90% of HPV-related anal cancer and genital warts in males and females worldwide,” director of the Center for Infection Research in Cancer at Moffitt, Anna R. Guiliano, PhD, explained in the press release.
In a phase 3 randomized study consisting of 105 study sites, researchers from 18 countries set out to compare the effectiveness of Gardasil 9, with the older Gardasil. The researchers enrolled 14,215 women between the ages of 16 and 26 and randomly put them into 2 groups: one receiving Gardasil 9, and the other receiving Gardasil. They followed up on the participants for 6 years post-vaccination.
They found that Gardasil 9 “has long-term activity against HPV infection and disease,” according to the press release. In fact, the improved vaccine cut down on the risk of developing “HPV 31/33/45/52/58-related cervical, vulvar, and vaginal disease by 97.7% when compared with Gardasil, and the 2 vaccines had similar activity at preventing HPV 6/11/16/18-associated disease.” Furthermore, Gardasil 9 was also “highly effective” in cutting down on the risk of developing “cervical cell abnormalities, biopsies, and definitive therapies” associated with HPV 31/33/45/52/58.
In 2015, Gardasil 9 first became available for use in females and males between the ages of 9 and 36 as a means of protection against HPV-related cancers as well as genital warts. Researchers postulate that increased use of this vaccine can work towards “greatly reducing the incidence and mortality of HPV-associated diseases,” according to the press release.
The researchers posit that the findings from this phase 3 study “support comprehensive vaccination programs and inform public health decision related to implementation.”