GARDASIL 9 is a vaccine indicated for the prevention of various diseases caused by specific types of Human Papillomavirus (HPV). The primary target group includes both girls and boys aged 9 through 45 years. It is designed to prevent:
- Cervical, vulvar, vaginal, anal, oropharyngeal, and other head and neck cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58.
- Genital warts (condyloma acuminata) caused by HPV types 6 and 11.
- Precancerous lesions:
- Cervical intraepithelial neoplasia (CIN) grades 1, 2, and 3.
- Vulvar intraepithelial neoplasia (VIN) grades 2 and 3.
- Vaginal intraepithelial neoplasia (VaIN) grades 2 and 3.
- Anal intraepithelial neoplasia (AIN) grades 1, 2, and 3.
Important Notes:
- The vaccine is not a treatment for existing HPV infections or lesions.
- Continued screening for cancers is required even after vaccination.
GARDASIL 9 Dosage Information
The standard dosage for GARDASIL 9 is 0.5 mL per dose, administered via intramuscular injection. The vaccine schedule depends on the patient’s age:
- 9 through 14 years:
- 2-dose schedule at 0 months and 6-12 months.
- 3-dose schedule at 0, 2, and 6 months (if required).
- 15 through 45 years:
- 3-dose schedule at 0, 2, and 6 months.
GARDASIL 9 Key Points:
- If the second dose in the 2-dose regimen is administered earlier than 5 months after the first dose, a third dose is required.
- The vaccine should be administered in the deltoid or anterolateral thigh region.
- Patients should be observed for 15 minutes after administration due to the potential for syncope.
GARDASIL 9 Side Effects and Precautions
The most commonly reported side effects are localized to the injection site and include:
- Injection-site pain:
- 89.9% in women aged 16-26 years.
- 71.5% in boys aged 9-15 years.
- Injection-site swelling:
- 40.0% in women aged 16-26 years.
- 47.8% in boys aged 9-15 years.
- Headache:
- 14.6% in women aged 16-26 years.
- 11.4% in boys aged 9-15 years.
GARDASIL 9 Serious Adverse Reactions:
- Syncope: Occasional fainting episodes, sometimes associated with seizure-like activity. Observation is recommended for 15 minutes post-injection.
- Allergic Reactions: Patients with hypersensitivity to yeast or previous doses of GARDASIL® or GARDASIL 9 should not receive the vaccine.
GARDASIL 9 Postmarketing Experience:
- Rare reports of autoimmune hemolytic anemia, Guillain-Barré syndrome, and acute disseminated encephalomyelitis were noted.
GARDASIL 9 Clinical Studies and Real-World Outcomes
In clinical trials, GARDASIL 9 has shown high efficacy in preventing HPV-related diseases. Here are some of the key findings from the clinical studies:
- Girls and Women (16-26 years):
- 98.2% efficacy in preventing HPV 16- and 18-related CIN 2/3 and adenocarcinoma in situ (AIS).
- 100% efficacy in preventing HPV 16- or 18-related VIN 2/3 and VaIN 2/3.
- Boys and Men (16-26 years):
- 90.6% efficacy in preventing HPV 6, 11, 16, and 18-related external genital lesions.
- Extended Efficacy: Follow-up studies indicated 100% efficacy against cervical and genital disease for up to 60 months post-vaccination.
GARDASIL 9 Drug Interactions
While no extensive studies on GARDASIL 9 interactions with other medications have been conducted, caution is advised when co-administering with immunosuppressive therapies, as these can reduce the vaccine’s efficacy.
GARDASIL 9 Use in Specific Populations
- Pregnancy: Data from clinical studies do not suggest an increased risk of birth defects when GARDASIL 9 is administered during pregnancy, but pregnant women should typically defer vaccination.
- Lactation: There is insufficient data to assess the impact of the vaccine on breastfeeding infants, though the benefits of breastfeeding should be weighed against the mother’s need for the vaccine.
- Pediatric Use: Safety and effectiveness are established in individuals 9 years and older. Efficacy in children younger than 9 years is not established.