Usage
-
This vaccine is prescribed for active immunization against infection caused by the Hepatitis A virus (HAV). It is recommended for pre-exposure prophylaxis of individuals at increased risk of infection and post-exposure prophylaxis. This includes individuals traveling to endemic areas, residents of communities with high endemic rates or recurrent outbreaks, those living or working in institutional settings with ongoing HAV transmission (correctional facilities, etc.), individuals with chronic liver disease, individuals with lifestyles that increase infection risk (e.g., intravenous drug use), and certain occupational groups (e.g., zookeepers, veterinarians handling non-human primates).
-
Pharmacological classification: Vaccine (Viral Vaccine, Live Attenuated).
-
Mechanism of Action: This vaccine stimulates the immune system to produce antibodies against HAV, providing long-term active immunity against the virus. It mimics a natural infection, triggering an immune response without causing the disease.
Alternate Names
- BIOVAC-A and Mevac-A are known brand names. There aren’t broadly used international variations for the generic name “Freeze-dried Live Attenuated Hepatitis A Vaccine,” though specific brand names may differ.
How It Works
- Pharmacodynamics: The vaccine induces an immune response, specifically the production of antibodies against the Hepatitis A virus. These antibodies neutralize the virus upon subsequent exposure, preventing infection.
- Pharmacokinetics: The live attenuated virus in the vaccine replicates locally at the injection site. This replication is limited and does not cause the disease but does trigger the immune response. The vaccine does not circulate systematically to a significant degree. Elimination of the attenuated virus is primarily through immune-mediated mechanisms.
- Mode of Action: The attenuated HAV in the vaccine activates both humoral and cellular immune responses. It stimulates the production of HAV-specific antibodies, particularly IgG antibodies.
- Receptor Binding/Enzyme Inhibition: Specific information on receptor binding is limited, but the attenuated virus interacts with cells of the immune system to initiate the immune response. There is no direct enzyme inhibition or neurotransmitter modulation.
- Elimination Pathways: The vaccine components are eliminated by usual bodily processes once the immune response is triggered.
Dosage
Standard Dosage
Adults: A single dose of 0.5 ml is administered subcutaneously, preferably over the deltoid muscle of the upper arm.
Children (over 1 year of age): A single dose of 0.5 ml is administered subcutaneously, preferably over the deltoid muscle of the upper arm.
Special Cases:
- Elderly Patients: Standard adult dosage.
- Patients with Renal Impairment: Standard adult dosage.
- Patients with Hepatic Dysfunction: Standard adult dosage as the vaccine does not rely heavily on hepatic metabolism.
- Patients with Comorbid Conditions: In general, the standard adult dose applies. Consider individual circumstances and consult specialist advice for complex or unusual situations.
Clinical Use Cases
The vaccine’s use is preventive, focusing on pre-exposure prophylaxis. Dosing remains consistent across use cases. It is not typically used in the context of intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
No specific dosage adjustments are typically necessary.
Side Effects
Common Side Effects
- Pain, redness, swelling, and induration at the injection site.
- Mild fever, headache, fatigue.
Rare but Serious Side Effects
- Allergic reactions (e.g., anaphylaxis).
Long-Term Effects
No long-term adverse effects are known to be associated with this vaccine.
Adverse Drug Reactions (ADR)
Contraindications
- Hypersensitivity to any component of the vaccine.
- Severe illness with or without fever.
Drug Interactions
- Immunosuppressants may reduce the effectiveness of the vaccine.
- Concurrent administration with other vaccines is generally safe but may be separated by a few weeks to monitor side effects separately if necessary.
Pregnancy and Breastfeeding
- Information is limited regarding the safety of this specific vaccine during pregnancy and breastfeeding. Consult specialist advice.
Drug Profile Summary
- Mechanism of Action: Stimulates active immunity by inducing antibody production against HAV.
- Side Effects: Injection site reactions, mild systemic symptoms. Rarely, allergic reactions.
- Contraindications: Hypersensitivity, severe illness.
- Drug Interactions: Immunosuppressants.
- Pregnancy & Breastfeeding: Consult specialist advice.
- Dosage: Single dose of 0.5 ml subcutaneously.
- Monitoring Parameters: Observe for any immediate reactions post-vaccination.
Popular Combinations
- Combined Hepatitis A and Hepatitis B vaccines are available.
Precautions
- Standard precautions for vaccine administration. Screen for contraindications before administration.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Freeze-dried Live Attenuated Hepatitis A Vaccine?
A: A single 0.5ml dose is given subcutaneously.
Q2: Who should receive this vaccine?
A: Individuals at increased risk of HAV infection, including travelers to endemic areas and those with chronic liver disease.
Q3: Are booster doses required?
A: A single dose usually provides long-term protection; boosters are not routinely recommended.
Q4: Can this vaccine be given to children?
A: Yes, it is approved for children over one year of age.
Q5: What are the common side effects?
A: Pain, redness, and swelling at the injection site, as well as mild fever or headache.
Q6: What if a patient has a mild illness?
A: Vaccination should be postponed until the illness resolves.
Q7: Is this vaccine safe for immunocompromised individuals?
A: Consult specialist advice as immunosuppression may reduce vaccine effectiveness.
Q8: Can this vaccine be given with other vaccines?
A: Generally safe, but consider spacing administrations to monitor side effects of each vaccine individually.
Q9: What is the duration of protection provided by this vaccine?
A: While long-term immunity is expected, the precise duration is not definitively established and may vary among individuals.
