Future HPV Vaccine Strain Coverage
Yes, future HPV vaccines will cover more strains, and this has already occurred—the 9-valent vaccine (Gardasil-9) now covers 9 HPV strains compared to the original 4 strains, and further expansion is theoretically possible and under development. 1
Current Vaccine Evolution
The HPV vaccine landscape has already expanded significantly:
The 9-valent vaccine (Gardasil-9) is now the recommended HPV vaccine in the United States, covering HPV types 6,11,16,18,31,33,45,52, and 58—more than double the original quadrivalent vaccine's coverage. 1
This expanded coverage protects against approximately 84% of HPV-related cancers in women, compared to 70% with the original bivalent/quadrivalent vaccines. 1
The additional five high-risk types (31,33,45,52,58) account for an additional 14% of HPV-related cancers in women and 4% in males beyond what types 16 and 18 cover. 1
Evidence for Continued Development
The scientific literature strongly supports ongoing vaccine development:
VLP vaccines for all important carcinogenic HPV types may theoretically be produced, as acknowledged by the American Cancer Society. 2
Current research is actively exploring vaccines with broader HPV type coverage, with emphasis on incorporating L1 proteins from additional HPV subtypes. 3
Development efforts are focusing on optimizing prophylactic vaccines by including more HPV subtypes and exploring novel adjuvants that could reinforce cellular immune responses. 3
Clinical Implications of Expanded Coverage
The 9-valent vaccine has demonstrated robust efficacy:
The vaccine showed 97% efficacy in preventing cervical, vulvar, and vaginal cancer precursor lesions related to the five additional types (31,33,45,52,58). 1
The antibody response against the original 4 types (6,11,16,18) in the 9-valent vaccine was non-inferior to the quadrivalent vaccine, meaning no protection was lost while gaining additional coverage. 1
Important Limitations and Caveats
Despite expanded coverage, critical gaps remain:
Even the 9-valent vaccine does not cover all cancer-causing HPV types, and cervical cancer screening remains essential even in vaccinated individuals. 1
The reduction of cervical cancer risk depends on multiple factors: degree of vaccination coverage, number of carcinogenic HPV types targeted, durability of protection, and continued adherence to screening guidelines. 2
Screening will continue to be necessary for the foreseeable future to protect against non-vaccine HPV types and to protect those who were already infected before vaccination. 2
Future Directions
Research is pursuing several avenues for next-generation vaccines:
Alternative expression systems and delivery platforms are being developed to create cheaper, more accessible vaccines with broader cross-protection. 4
Therapeutic HPV vaccines (as opposed to prophylactic) are under development for treating existing infections and HPV-related diseases. 3
Novel formulation strategies, optimized dosing schedules, and age expansion are being explored to address vaccine hesitancy and availability barriers. 3