Merck has released a comprehensive publication on the long-term follow-up (LTFU) data for Gardasil 9 (Human Papillomavirus 9-valent Vaccine, Recombinant) in the journal Pediatrics. This study, conducted over a decade from 2009 to 2021 across 13 countries and five continents, sheds light on the sustained immunogenicity and safety of the vaccine for both girls and boys who received a three-dose regimen between the ages of 9 and 15.
Gardasil 9 has demonstrated its effectiveness in guarding against a spectrum of HPV-related illnesses. In the United States, this vaccine is authorized for use in females between the ages of 9 and 45, offering protection against cervical, vulvar, vaginal, anal, oropharyngeal, and various head and neck cancers caused by certain HPV types. Additionally, it is approved for males aged 9 through 45 to prevent anal, oropharyngeal, and other head and neck cancers, as well as anal precancerous or dysplastic lesions and genital warts caused by certain HPV strains.
The long-term study yielded encouraging results, with no cases of HPV-related high-grade disease, specific cancers, or genital warts reported in boys and girls who received the vaccine between the ages of 9 and 15 over the ten-year observation period.
HPV (Human Papillomavirus) is responsible for a significant percentage of cervical cancers, genital warts, and certain vulvar, vaginal, and anal cancers. While most individuals naturally clear the virus, it can sometimes persist, potentially leading to serious health issues, including cancer.
Regarding the primary objective of immunogenicity, the study found sustained HPV-antibody responses a decade after the third vaccine dose. Most participants remained seropositive for the targeted HPV types, with 94.9% to 100% showing seropositivity at Month 126, depending on the HPV type.
The study's secondary objective assessed the incidence of persistent infection and disease related to vaccine-targeted HPV types. Female participants were monitored for up to 11.0 years post the third dose, with no cases of high-grade disease or certain cancers observed. In boys, there were no cases of vaccine-targeted HPV-type disease or specific cancers noted.
Notably, the study did not report any serious adverse events or deaths related to GARDASIL 9 throughout the LTFU period. The primary reasons for discontinuation from the study were participant withdrawal or loss of follow-up.
HPV is a highly prevalent virus, infecting most sexually active individuals at some point. While most HPV infections clear naturally, some may lead to cancers and other health problems. In the United States, tens of thousands of people are diagnosed with HPV-related cancers yearly, and worldwide, cervical cancer is the fourth most prevalent cancer in women. Detecting HPV-related cancers, except for cervical cancer, typically lacks routine screening protocols, making vaccination a crucial preventive measure.