Usage
- Medical Conditions: Human Papillomavirus 9-valent (9vHPV) vaccine, recombinant is prescribed for the prevention of certain cancers and diseases caused by the nine human papillomavirus (HPV) types (6, 11, 16, 18, 31, 33, 45, 52, and 58) included in the vaccine. Specifically, it helps protect against cervical, vulvar, vaginal, and anal cancers in females; anal, penile, and oropharyngeal cancers in males and females; and genital warts in both sexes.
- Pharmacological Classification: Vaccine (viral)
- Mechanism of Action: 9vHPV vaccine stimulates an immune response by inducing the production of type-specific neutralizing antibodies against the nine HPV types contained in the vaccine. These antibodies prevent the initial establishment of HPV infection and subsequent viral persistence responsible for HPV-related diseases and cancers.
Alternate Names
- Human Papillomavirus 9-valent Vaccine, Recombinant, Adsorbed
- Brand Names: Gardasil 9
How It Works
- Pharmacodynamics: 9vHPV vaccine mimics a natural HPV infection, triggering the body’s immune system to produce antibodies against the nine HPV types in the vaccine. These antibodies neutralize HPV and prevent the virus from infecting cells. The vaccine does not contain live virus, DNA, or infectious material, so it cannot cause HPV infection.
- Pharmacokinetics: 9vHPV vaccine is administered intramuscularly. The vaccine components are released from the injection site and processed by the immune system, resulting in antibody production. The exact pharmacokinetic parameters (absorption, distribution, metabolism, and elimination) are not typically studied for vaccines in the same way as they are for therapeutic drugs.
- Mode of Action: The vaccine contains virus-like particles (VLPs) of the L1 major capsid protein of the nine HPV types. These VLPs resemble the outer shell of HPV but lack viral DNA, making them non-infectious. The immune system recognizes the VLPs as foreign antigens and mounts an immune response, producing neutralizing antibodies specific to each HPV type.
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Not applicable, as 9vHPV vaccine’s mechanism of action involves stimulating an immune response rather than directly interacting with cellular receptors, enzymes, or neurotransmitters.
- Elimination Pathways: The components of the vaccine are presumed to be broken down and eliminated through normal physiological processes.
Dosage
Standard Dosage
Adults (9 through 45 years):
- 0.5 mL intramuscularly.
- Two-dose schedule: First dose at any time, second dose 6-12 months later (minimum interval: 5 months).
- Three-dose schedule: First dose at any time, second dose 1-2 months later, third dose 6 months after the first dose (minimum intervals: 4 weeks between doses 1 and 2; 12 weeks between doses 2 and 3; 5 months between doses 1 and 3).
- Individuals 27 years and older may receive the vaccine following shared decision-making with a healthcare provider.
Children (9 through 14 years):
- 0.5 mL intramuscularly.
- Two-dose schedule: First dose at any time, second dose 6-12 months later (minimum interval: 5 months).
- Three-dose schedule may be used.
- Pediatric safety considerations are similar to those for adults. The vaccine has a well-established safety profile in this age group.
Special Cases:
- Elderly Patients (over 45 years): Not indicated.
- Patients with Renal Impairment: No dose adjustment necessary.
- Patients with Hepatic Dysfunction: No dose adjustment necessary.
- Patients with Comorbid Conditions: Generally well-tolerated. For patients with bleeding disorders, the injection should be administered with caution. For immunocompromised individuals (including those with HIV), a three-dose schedule is recommended.
Clinical Use Cases
Not applicable. 9vHPV vaccine is a preventative vaccine, not for use in acute clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
No specific dose modifications based on patient-specific factors (renal/hepatic dysfunction, metabolic disorders, or genetic polymorphisms) are required.
Side Effects
Common Side Effects:
- Injection site reactions (pain, swelling, redness, itching, bruising, bleeding)
- Headache
- Fever
- Fatigue
- Nausea
- Dizziness
Rare but Serious Side Effects:
- Severe allergic reactions (anaphylaxis)
- Syncope (fainting), sometimes accompanied by tonic-clonic movements
Long-Term Effects:
No long-term adverse effects have been identified.
Adverse Drug Reactions (ADR):
Any severe or unexpected adverse events should be reported to the relevant health authorities.
Contraindications
- History of severe allergic reaction to any component of the vaccine, including yeast.
- Severe allergic reaction after a previous dose of 9vHPV vaccine or quadrivalent HPV vaccine.
Drug Interactions
- Immunosuppressants may reduce the immune response to the vaccine.
- Concomitant administration with other vaccines is generally well-tolerated. 9vHPV can be given with a combined booster vaccine containing diphtheria and tetanus toxoids with either pertussis and/or inactivated poliovirus vaccine (dTap, dT-IPV, or dTap-IPV) at a separate injection site.
- Hormonal contraceptives do not affect the vaccine’s effectiveness.
Pregnancy and Breastfeeding
- Pregnancy: Limited data suggest that exposure to 9vHPV vaccine during pregnancy does not pose a risk to the fetus, but further studies are ongoing. If pregnancy occurs after initiating the vaccination series, remaining doses should be delayed until after delivery. Routine pregnancy testing is not required before vaccination.
- Breastfeeding: The effect of 9vHPV vaccine on breastfed infants is unknown. However, there have been no reported adverse events thought to be vaccine-related in breastfed infants whose mothers received HPV vaccines.
Drug Profile Summary
- Mechanism of Action: Stimulates an immune response and the production of neutralizing antibodies against nine HPV types.
- Side Effects: Commonly injection site reactions, headache, fever, fatigue. Rarely severe allergic reaction or syncope.
- Contraindications: Severe allergy to vaccine components, including yeast, or a previous dose of an HPV vaccine.
- Drug Interactions: Immunosuppressants may reduce response. Concomitant administration with other vaccines is generally safe.
- Pregnancy & Breastfeeding: Limited safety data suggest no fetal risk. Vaccination should be delayed until after pregnancy, and effects on breastfed infants are not fully known.
- Dosage: 0.5 mL IM. Two-dose schedule for 9-14 years and potentially for those older than 26, otherwise three doses.
- Monitoring Parameters: Observe for immediate allergic reactions and syncope after administration.
Popular Combinations
- Co-administration with other adolescent vaccines, like meningococcal and Tdap, at separate injection sites.
Precautions
- General Precautions: Observe patients for 15 minutes after administration for syncope. Screen for contraindications.
- Specific Populations:
- Pregnant Women: Postpone vaccination until after pregnancy.
- Breastfeeding Mothers: Safety unknown but no adverse events reported.
- Children & Elderly: Approved for ages 9-45. Not indicated for those older than 45.
- Menstruating Individuals: No specific precautions.
- Lifestyle Considerations: No specific lifestyle restrictions associated with the vaccine.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Human Papillomavirus 9-Valent Vaccine, Recombinant?
A: 0.5 mL intramuscularly. The number of doses and schedule depend on the age at the time of the first dose: two doses (0, 6-12 months) for ages 9-14 or three doses (0, 1-2, 6 months) for ages 15-45.
Q2: Can Gardasil 9 be given to someone who has already had a different HPV vaccine?
A: Yes, individuals previously vaccinated with the quadrivalent HPV vaccine can receive Gardasil 9. However, completing the full Gardasil 9 series is important for optimal protection.
Q3: Does Gardasil 9 protect against all types of HPV?
A: No, Gardasil 9 protects against the nine HPV types included in the vaccine but not all types. It provides strong protection against most HPV-related cancers and genital warts, but other preventative measures against STIs are still recommended.
Q4: How long does protection from Gardasil 9 last?
A: Current data indicate protection lasting at least 10 years after vaccination. Long-term studies are ongoing to determine the need for a booster dose.
Q5: Can Gardasil 9 be given during pregnancy?
A: Current data suggest no risk to the fetus, but due to limited information, vaccination should be postponed until after pregnancy. Routine pregnancy testing is not necessary before vaccination.
Q6: What are the common side effects of Gardasil 9?
A: The most common side effects are mild and include injection site reactions (pain, swelling, redness), headache, fever, fatigue, nausea, and dizziness.
Q7: Is Gardasil 9 a live vaccine?
A: No, Gardasil 9 is a non-infectious recombinant vaccine containing VLPs, not live virus.
Q8: Can males receive Gardasil 9?
A: Yes, Gardasil 9 is indicated for males aged 9 through 45 for the prevention of anal cancer, genital warts, and other HPV-related cancers.
Q9: Is Gardasil 9 effective if given to someone who is already infected with HPV?
A: Gardasil 9 will not treat existing HPV infections or related diseases. It prevents new infections with the nine covered HPV types.
