Usage
- Medical Conditions: Human Papillomavirus Bivalent (Types 16 and 18) Vaccine, Recombinant (Cervarix) is a vaccine indicated for the prevention of diseases caused by HPV types 16 and 18, including cervical cancer, cervical intraepithelial neoplasia (CIN) grade 1, CIN 2 or worse, and adenocarcinoma in situ. Although this vaccine is still used in some countries, it is no longer available in the United States, where the 9-valent HPV vaccine is preferred.
- Pharmacological Classification: Vaccine
- Mechanism of Action: Stimulates an immune response against HPV types 16 and 18 by producing noninfectious virus-like particles (VLPs) resembling HPV. These VLPs trigger the body to create antibodies, which protect against future HPV infections by the covered types.
Alternate Names
- Cervarix
- Human Papillomavirus Bivalent Vaccine
How It Works
- Pharmacodynamics: The vaccine induces the production of neutralizing antibodies against HPV types 16 and 18. These antibodies prevent infection by blocking the virus from entering host cells.
- Pharmacokinetics: Administered intramuscularly (IM), the vaccine components are slowly absorbed from the injection site. The recombinant L1 proteins are processed and presented to the immune system, triggering antibody production. Specific metabolic and elimination pathways have not been characterized. The vaccine itself contains no live biological material; after administration, the body breaks down the remaining non-active substances of the injection, and these harmless waste products are eliminated naturally.
- Mode of Action: The vaccine contains L1 proteins, the major capsid proteins of HPV types 16 and 18. These L1 proteins self-assemble into virus-like particles (VLPs). Upon administration, these VLPs mimic a natural HPV infection, stimulating both humoral and cellular immune responses.
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Not applicable, as the vaccine’s mode of action relies on immune stimulation, not direct interaction with receptors, enzymes, or neurotransmitters.
- Elimination Pathways: Not specifically characterized.
Dosage
Standard Dosage
Adults (Ages 9–26 years):
0.5 mL IM administered in a 3-dose series at 0, 1, and 6 months. Current guidelines suggest that a 2-dose schedule may be sufficient in patients younger than 21 years of age.
Children (Ages 9-14 years):
0.5 mL IM administered in a 2-dose series at 0 and 6-12 months. If the second dose is given before 5 months, an additional dose is recommended.
Special Cases:
- Elderly Patients (≥27 years): This vaccine has been approved for use up to age 45. A 3-dose schedule (0, 2, 6 months) may be appropriate, but shared decision-making is recommended.
- Patients with Renal Impairment: No dose adjustments are necessary.
- Patients with Hepatic Dysfunction: No dose adjustments are necessary.
- Patients with Comorbid Conditions: No specific dosage adjustments are routinely recommended, but clinical judgment should be exercised for immunocompromised patients (including HIV-positive individuals), who may require a 3-dose schedule (0, 1-2, 6 months).
Clinical Use Cases
This medication is exclusively for prophylactic (preventive) use, not for the treatment of established HPV infection or associated diseases. It is not relevant to the listed clinical settings (intubation, surgical procedures, mechanical ventilation, ICU use, emergency situations).
Dosage Adjustments
No specific adjustments are routinely necessary based on patient-specific factors. However, clinicians should consider a 3-dose schedule for immunocompromised patients.
Side Effects
Common Side Effects:
- Injection site reactions (pain, swelling, redness)
- Headache
- Fatigue
- Myalgia
- Nausea
Rare but Serious Side Effects:
- Severe allergic reactions (e.g., anaphylaxis)
- Syncope (fainting)
Long-Term Effects:
No significant long-term side effects have been reported.
Adverse Drug Reactions (ADR):
Contraindications
- History of severe allergic reaction (e.g., anaphylaxis) to any vaccine component (including yeast or polysorbate 80).
Drug Interactions
- Immunosuppressants (e.g., chemotherapy, radiation therapy) may reduce the vaccine’s effectiveness.
- No clinically significant interactions with commonly prescribed medications, OTC drugs, or food/lifestyle factors have been reported.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: B (FDA classification prior to the drug’s discontinuation in the US)
- This vaccine is generally avoided during pregnancy, although inadvertent administration is not an indication for pregnancy termination.
- Breastfeeding: Vaccination is not contraindicated during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Induces antibody production against HPV types 16 and 18 via VLPs.
- Side Effects: Common: injection site reactions, headache, fatigue, myalgia, nausea. Rare but serious: anaphylaxis, syncope.
- Contraindications: Severe allergy to any vaccine component.
- Drug Interactions: Immunosuppressants may reduce efficacy.
- Pregnancy & Breastfeeding: Generally avoided during pregnancy; compatible with breastfeeding.
- Dosage: 3-dose series (0, 1, 6 months) or 2-dose series (0, 6-12 months) IM; special considerations for immunocompromised individuals.
- Monitoring Parameters: Observation for syncope for 15 minutes post-vaccination.
Popular Combinations
Not applicable. The vaccine is generally administered alone.
Precautions
- Observe patients for 15 minutes post-vaccination for syncope.
- Pre-screening for contraindications (e.g., allergy history) is essential.
- Postpone vaccination in patients with acute febrile illness.
- Avoid during pregnancy, unless accidental exposure has already occurred.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Human Papillomavirus Bivalent Vaccine, Recombinant?
A: The standard dosage is 0.5 mL IM, administered in a 2 or 3 dose series depending on the patient’s age. See detailed dosage guidelines above.
Q2: How effective is Cervarix?
A: Highly effective in preventing HPV 16 and 18-related cervical precancers and cancers.
Q3: Can boys or men receive Cervarix?
A: Cervarix is only approved for use in females.
Q4: What should I do if a patient faints after receiving Cervarix?
A: Ensure the patient is in a supine position to restore cerebral perfusion and monitor vital signs.
Q5: Does Cervarix protect against all types of HPV?
A: No, it only protects against types 16 and 18. It does not protect against all HPV types, nor against conditions not caused by HPV.
Q6: Can Cervarix be given during pregnancy?
A: It’s generally avoided during pregnancy, though inadvertent exposure isn’t a reason to terminate the pregnancy.
Q7: What are the common side effects of Cervarix?
A: Injection site reactions (pain, swelling, redness), headache, fatigue, myalgia, and nausea are common.
Q8: Is Cervarix a live vaccine?
A: No. Cervarix consists of non-infectious virus-like particles.
Q9: Can Cervarix treat existing HPV infections?
A: No. Cervarix is exclusively for the prevention of HPV infections, and it does not cure an existing infection.
Q10: How long does protection from Cervarix last?
A: Long-term studies suggest protection lasts for many years, but the exact duration is still under investigation. Boosters are currently not recommended.
