Dosing and uses of Influenza virus vaccine (H5N1)
Adult dosage forms and strengths
emulsion for IM injection
- 3.75mcg/0.5mL; contains hemagglutinin (HA) of the influenza virus strain within the vaccine
H5N1 Influenza (Avian Flu)
Indicated for active immunization for the prevention of disease caused by the influenza A virus H5N1 subtype (ie, A/Indonesia/05/2005)
2-dose immunization series
3.75 mcg (0.5 mL) IM once; administer second 0.5 mL dose 21 days later
Dosing Considerations
Contains AS03 adjuvant; in clinical studies, the adjuvanted formulation stimulated the required immune response while using a smaller amount of antigen as compared to a formulation without adjuvant
Specific strain: A/Indonesia/05/2005
Also contains thimerosal, chicken egg protein
Pediatric dosage forms and strengths
<18 years: Safety and efficacy not established
Influenza virus vaccine (H5N1) adverse (side) effects
>10%
Injection site pain (83%)
Myalgia (45%)
Headache (35%)
Fatigue (34%)
Arthralgia (25%)
Shivering (17%)
Sweating (11%)
1-10%
Swelling (10%)
Injection site erythema (9%)
Fever (5%)
Postmarketing Reports
Immune system disorders: Anaphylaxis, allergic reactions
Nervous system disorders: Febrile convulsions, Guillain-Barré syndrome, narcolepsy, somnolence
Skin and subcutaneous tissue disorders: Angioedema, generalized skin reactions, urticaria
General disorders and administration site conditions: Injection site reactions (including inflammation, mass, necrosis, and ulcer)
Warnings
Contraindications
Known severe allergic reactions (eg, anaphylaxis) to any component of the vaccine, including egg protein, or after a previous dose of an influenza vaccine
Cautions
Hypersensitivity may occur; appropriate medical treatment, including epinephrine, and supervision should be available to manage possible anaphylactic
History of Guillain-Barre syndrome following prior vaccine
Syncope can occur with administration of injectable vaccines
May not be effective in preventing disease caused by influenza A (H5N1) virus in immunosuppressed persons, including individuals receiving immunosuppressive therapy
Pregnancy and lactation
Pregnancy category: B
Lactation: Distributed in human breast milk; use with caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Influenza virus vaccine (H5N1)
Mechanism of action
Influenza vaccines induce antibodies against the viral hemagglutinin antigen in the vaccine, which then blocks viral attachment to human respiratory cells
The mechanism of action of type A (H5N1) influenza virus is not well understood; promotes active immunity to avian influenza
Pharmacokinetics
In clinical trials, a 4-fold increase in antibody titers was seen in up to ≥70% of patients aged 18-64 years, and ≥60% aged ≥65 years
Administration
IM Preparation
Emulsion for injection supplied as 2 separate vials, a vial of H5N1 antigen and a vial of AS03 adjuvant
The 2 vials must be combined before use
Once combined, the resulting volume provides 10 doses (0.5 mL each) in a multi-dose viaL
Administer vaccine within 24 hr after combining H5N1 antigen and AS03 adjuvant
Do not mix with any other vaccine
IM Administration
If after mixing, the vaccine is stored refrigerated, place the vaccine at room temperature for a minimum of 15 minutes prior to administration
Mix the vaccine thoroughly by inversion before each administration
Inspected visually for particulate matter and discoloration prior to administration
Use a sterile needle (23-gauge is recommended) and sterile syringe for each dose withdrawal from the multi-dose vial and for vaccine administration
Preferred site for IM injection is the deltoid muscle of the upper arm
Storage
Do not freeze; discard if frozen
Protect from light
Before mixing vials: Refrigerate between 2-8°C (36-46°F)
After mixing vials
- Use within 24 hr
- Store either refrigerated between 2-8°C (36-46°F) or at room temperature 30°C (86°F) for up to 24 hr
