Human Papillomavirus Bivalent Vaccine, Recombinant

Usage

• Medical Conditions: Human Papillomavirus Bivalent (Types 16 and 18) Vaccine, Recombinant is prescribed for the prevention of diseases caused by Human Papillomavirus (HPV) types 16 and 18. These diseases include cervical cancer, precancerous cervical lesions (CIN 2/3 and adenocarcinoma in situ), and genital warts. It is vital to note this vaccine does not protect against all HPV types, thus other preventative measures are still necessary.

• Pharmacological Classification: Vaccine

• Mechanism of Action: The vaccine stimulates an immune response against HPV types 16 and 18 by producing antibodies that prevent infection. It does not treat existing HPV infections.

Alternate Names

• Cervarix

How It Works

• Pharmacodynamics: This vaccine mimics a natural HPV infection to trigger the immune system to create antibodies against HPV types 16 and 18. These antibodies neutralize the virus, preventing it from infecting cells.

• Pharmacokinetics: Administered intramuscularly, the vaccine’s components are processed and presented to the immune system.

• Mode of Action: The vaccine contains virus-like particles (VLPs) assembled from recombinant L1 proteins, which are the major capsid proteins of HPV types 16 and 18. These VLPs resemble the outer shell of the HPV virus but lack viral DNA. When injected, they stimulate the body to produce neutralizing antibodies against HPV 16 and 18, providing long-term protection.

• Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: The vaccine’s effect is not mediated by receptor binding, enzyme inhibition, or neurotransmitter modulation. Instead, it works by eliciting a humoral immune response (antibody production).

• Elimination Pathways: The exact elimination pathways are not fully characterized, but components are likely processed and eliminated through typical metabolic processes.

Dosage

Standard Dosage

Adults (9-26 years):

• 0.5 mL intramuscularly, administered as a two-dose series at 0 and 6 months. Alternatively, if the first two doses are administered less than five months apart, a third dose is required at least 6 months after the first dose.

Children (9-14 years):

• Same as adults.

Special Cases:

• Elderly Patients (27-45 years): May receive the HPV vaccine. The recommended schedule is three doses (0, 1-2, and 6 months) as with individuals older than 15.

• Patients with Renal Impairment: No dose adjustment is typically necessary.

• Patients with Hepatic Dysfunction: No dose adjustment is typically necessary.

• Patients with Comorbid Conditions: Assess on a case-by-case basis.

Clinical Use Cases

This vaccine is preventative—it’s not indicated for clinical use in acute settings like intubation, surgery, mechanical ventilation, ICU care, or emergency situations. Its use is strictly for preventing HPV-related conditions.

Dosage Adjustments

No specific dosage adjustments are indicated based on renal/hepatic dysfunction, metabolic disorders, or genetic polymorphisms.

Side Effects

Common Side Effects:

• Pain, redness, or swelling at the injection site
• Headache
• Fever
• Fatigue
• Nausea
• Muscle or joint pain

Rare but Serious Side Effects:

• Allergic reactions (e.g., anaphylaxis): This is extremely rare but requires immediate medical intervention.

• Syncope (fainting): Can occur after injection. Observation for 15 minutes post-vaccination is recommended.

Long-Term Effects: No significant long-term side effects have been reported.

Adverse Drug Reactions (ADR): Anaphylaxis, although rare, is the most significant ADR and requires immediate treatment.

Contraindications

• History of severe allergic reaction to any vaccine component (e.g., yeast, aluminum adjuvant, polysorbate 80).

Drug Interactions

• Concurrent use of immunosuppressants may reduce the vaccine’s efficacy.
• No significant interactions with commonly prescribed medications, OTC drugs, or food are known.

Pregnancy and Breastfeeding

• Pregnancy Safety Category: B. While not routinely recommended during pregnancy, it’s not believed to harm the fetus. If pregnancy occurs after starting the series, delay remaining doses until after delivery.

• Breastfeeding: Limited data suggest no adverse effects on breastfed infants.

Drug Profile Summary

• Mechanism of Action: Stimulates antibody production against HPV 16 and 18.

• Side Effects: Injection site reactions, headache, fever, fatigue, nausea.

• Contraindications: Hypersensitivity to vaccine components.

• Drug Interactions: Immunosuppressants may decrease effectiveness.

• Pregnancy & Breastfeeding: Generally safe, not routinely recommended during pregnancy.

• Dosage: 0.5 mL IM in a 2-dose series (0, 6 months) for individuals between 9 and 26 years. Three-dose schedule (0, 1-2, and 6 months) for individuals 27-45 years.

• Monitoring Parameters: Observe for allergic reactions and syncope post-vaccination.

Popular Combinations

Can be co-administered with other vaccines (using separate syringes and injection sites) like hepatitis B and meningococcal vaccines.

Precautions

• Observe patients for 15 minutes post-injection for syncope.
• Not recommended during pregnancy, but not an indication for termination if it occurs.
• Pre-screening for allergies is essential.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Human Papillomavirus Bivalent Vaccine, Recombinant?

A: For ages 9 through 26, two 0.5 mL doses are administered intramuscularly, typically in the deltoid muscle, at 0 and 6 months. For ages 27-45, three 0.5 mL doses are given at 0, 1-2, and 6 months.

Q2: Can boys receive the bivalent HPV vaccine?

A: The bivalent HPV vaccine (Cervarix) is licensed only for use in females. Other HPV vaccines are available and recommended for boys and men.

Q3: What are the most common side effects?

A: Common side effects include injection site reactions (pain, redness, swelling), headache, fever, fatigue, and nausea.

Q4: Is the vaccine effective if already exposed to HPV?

A: The vaccine does not treat existing HPV infections or related diseases. It helps protect against future infections with HPV types 16 and 18.

Q5: Does the vaccine protect against all HPV types?

A: No, the bivalent HPV vaccine protects only against types 16 and 18. It does not protect against all types of HPV. It does not prevent all cervical cancers or other HPV-related diseases.

Q6: Can this vaccine be given during pregnancy?

A: It’s not routinely recommended, but unintentional administration isn’t a reason for pregnancy termination. It’s advisable to delay the remaining doses until after delivery.

Q7: What should be done if a patient faints after the injection?

A: Observe the patient for 15 minutes post-vaccination. If fainting occurs, ensure adequate cerebral perfusion by laying the patient down and raising their legs.

Q8: Is there a risk of developing HPV or cancer from the vaccine?

A: No. The vaccine contains virus-like particles and not live HPV, therefore, it cannot cause HPV infection or cancer.

Q9: How long does protection from the vaccine last?

A: Current data suggest protection lasts for at least 10 years. Research is ongoing to determine the need for booster doses.