The Efficacy of Current Preventative Treatments Against the HPV Virus and Barriers to Adoption
Introduction: Two subtypes of the Human Papilloma Virus, HPV-16 and HPV-18, account for 50% and 10% of all cervical cancer cases respectively1. Preventative measures have been proven to be almost 100% effective against HPV-infiection2. However, two challenges still exist regarding the current HPV vaccine: a lack of therapeutic value for individuals infected by the HPV virus and vaccine rejection2-4. Studies have been conducted showing that combination therapies may provide therapeutic value for individuals infected with the HPV virus3. Studies have also been conducted showing that increasing knowledge related to vaccines does not significantly reduce long-term vaccine hesitancy4. Rather, the strength of key attitudes such as conspiratorial belief, disgust reactivity, and belief in an individualistic worldview impacts the extent of individual vaccine rejection5. These studies may provide insight on how to increase therapeutic value in current vaccination methods and reduce overall vaccine hesitancy3-5.
Methods: A monotherapy and combination therapy against TC-1 carcinoma expressed HPV-16 E6 and E7 without PDL1 in a mouse model was employed. The combination therapy included PDS0101, bintrafusp alfa, and NHS-IL-12. Treatment began one week after implanting the TC-1 carcinoma with a control PBS vaccine, weekly injections of the liposomal R-DOTAP adjuvant, and weekly injections of the PDS0101 vaccine. Antitumor effects and immune cell types were analyzed in the spleen IFN-gamma ELIspot and flow cytometry. Results: In monotherapy, PDS0101 decreased tumor volume and tumor weights compared to the PBS control (p < 0.01). In combination therapy, there is greater control against tumor activity compared to PDS0101 alone. With the combination therapy, 13/16 mice had tumors smaller than 300 mm3.
Methods: 585 participants 60 years of age and older were provided 3 educational leaflets related to influenza and sepsis.4 After participants read the leaflets, demographic information was obtained and participants returned for a follow-up study 3 months later4. During the follow-up study, participants were asked if they received vaccinations for influenza and/or pneumococci4. The design assessed knowledge about primary and secondary health diseases, perceptions of risk, and vaccination intentions4. In another study, 323 participants in 24 different countries were surveyed about attitudes towards vaccinations5. Questions included beliefs in conspiracy theories, tolerance towards impingement of freedoms, attitudes toward blood and needles, and attitudes related to societal control over the individuall5. Results: Educational leaflets increased knowledge on the selected primary and secondary health diseases4. Immediate risk perceptions and intentions for vaccinations were also increased4. However, increased knowledge only has some impact on increased intentions for vaccination long-term4. Individuals who have a high belief in conspiracy theories had much stronger antivaccination attitudes, followed by individuals who had a low tolerance towards impingement on freedoms, individuals who had an aversion towards blood and needles, and individuals who believe society should have very little control over the individual5.
Conclusions: Therapeutic vaccines are necessary to target viral antigens expressed by infected cells. A combination of different immunotherapeutic approaches, such as preventive prophylactic treatments as well as therapeutic treatments, can effectively eliminate HPV-associated tumors. Future research should focus on how increased knowledge impacts implementation intention to gain an understanding of the connection between long-term behaviors and new knowledge. Furthermore, by understanding the psychological factors behind vaccine hesitancy, there is a greater understanding of how the repetition of evidence-based information may not be productive in decreasing antivaccination sentiments. Rather, communication-based solutions should be of greater focus.
- Johnson CA, James D, Marzan A, Armaos M. Cervical cancer: An overview of pathophysiology and management. Seminars in Oncology Nursing. 2019;35(2):166-174. doi:10.1016/j.soncn.2019.02.003
- Zhou C, Tuong ZK, Frazer IH. Papillomavirus immune evasion strategies target the infected cell and the local immune system. Frontiers in Oncology. 2019;9. doi:10.3389/fonc.2019.00682
- Smalley Rumfield C, Pellom ST, Morillon II YM, Schlom J, Jochems C. Immunomodulation to enhance the efficacy of an HPV therapeutic vaccine. Journal for ImmunoTherapy of Cancer. 2020;8(1). doi:10.1136/jitc-2020-000612 https://jitc.bmj.com/content/8/1/e000612.long
- Eitze, S., Heinemeier, D., Schmid-Küpke, N. K., & Betsch, C. (2021). Decreasing vaccine hesitancy with extended health knowledge: Evidence from a longitudinal randomized controlled trial. Health Psychology, 40(2), 77–88. https://doi.org/10.1037/hea0001045
- Hornsey, M. J., Harris, E. A., & Fielding, K. S. (2018). The psychological roots of anti-vaccination attitudes: A 24-nation investigation. Health Psychology, 37(4), 307–315. https://doi.org/10.1037/hea0000586