Varivax: Live attenuated chickenpox vaccine
Varivax vaccine is live attenuated vaccine for chickenpox disease. It is used to prevent chickenpox disease. It contains Varicella zoster virus live attenuated OKA strain > 1350 PFU. It is available as lyophilized freeze dried powder form. Additionally it contains mannitol, dextran, sucrose, trehalose and human albumin. Other vial contains sterile water for injection IP.
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How is Varivax vaccine available?
Varivax vaccine is available in a packet that contains 2 vials. A vial contains a lyophilized freeze dried powder that contains live attenuated Varicella zoster virus OKA strain > 2000 PFU. Other vial contains sterile water for injection for dilution. The vials should be stored in packet to protect it from light.
How is Varivax vaccine stored?
· Before reconstitution, store the lyophilized vaccine in a freezer at a temperature between -58°F and +5°F (-50°C and -15°C).
· Before reconstitution, protect from light.
· Any freezer (eg, chest, frost-free) that reliably maintains a temperature between -58°F and +5°F (-50°C and -15°C) and has a separate sealed freezer door is acceptable for storing VARIVAX.
· May be stored at refrigerator temperature (36°F to 46°F, 2°C to 8°C) for up to 72 continuous hours prior to reconstitution. Vaccine stored at 36°F to 46°F (2°C to 8°C) which is not used within 72 hours of removal from +5°F (-15°C) storage should be discarded.
· The diluent should be stored separately at room temperature (68°F to 77°F, 20°C to 25°C), or in the refrigerator.
· The expired vaccine should not be used and discarded as per biomedical waste management protocol.
How is Varivax vaccine given?
Varivax vaccine is given by injection subcutaneous route. All the safety injection protocol should be followed while giving injection. The sterile water for injection first sucked into the sterile syringe. It is mixed into the lyophilized powder and agitated gently to mix the contents uniform solution. This solution is again sucked back to the syringe. The needle is changed for subcutaneous injection. The injection is given subcutaneously in deltoid region. The spirit used to clean the skin should be totally evaporated before giving injection. The contact of sterilizers should be avoided while mixing the contents to the vial. The used disposables should be discarded as per biomedical waste management protocol guidelines.
At what age is Varivax vaccine is given?
In routine immunization this Varivax vaccine is given at age more than 12 months 2 doses of 0.5 ml subcutaneous at least 3 months apart. Generally it is given at age 12 months and 4-5 years. For adolescents and adults Nexipox vaccine can be given 2 doses 0.5 ml 4-8 weeks apart.
What are side effects after Varivax vaccine?
Varivax vaccine is given to protect from chickenpox disease. Side effects are very few and usually milder than the disease.
· Fever may occur in less than 5 percent of those get Varivax vaccine. It can be mild to moderate grade and can be managed at home with oral medications paracetamol and sponging. It may last 1-3 days.
· Papulovescicular eruptions like chickenpox may occur in less than 4 percent of those got vaccine. These are usually milder and less lin number and usually last for a short duration.
· Like all other vaccines this vaccine can cause allergic reactions and anaphylaxis, the facility where the injection is given should be equipped with drugs and skilled personnel to manage the anaphylactic reaction.
How does Varivax vaccine works?
Varivax vaccine is live attenuated vaccine. It is used to protect from chickenpox disease. This vaccine contains live Varicella zoster virus OKA strain. This is live virus but not capacity to cause disease. This virus resembles the actual chickenpox causing virus. When this vaccine is injected this virus infects the person who got injection. It multiplies inside the body of the hosts. Then host immunity recognizes the virus and produces immune mechanism to fight against it. In the process immune mechanism also produces the memory to fight the virus. When real infection occurs with disease causing virus the immune system ramps up the mechanism to fight the virus rapidly and the chickenpox disease is prevented.
This is active form of immunization in which hosts himself/herself develops immunity inside the body against this virus.
To whom Varivax vaccine should not be given?
Varivax vaccine should not be given to
· Those who are pregnant should not get Varivax vaccine vaccine.
· Those who have leukemia should not get Varivax vaccine vaccine.
· Those who are immunosuppressant therapy should not get this vaccination.
· Those who are HIV AIDS patients with stage 3-4 disease should not get this vaccination.
Warnings With Varivax vaccine:
· This virus can rarely spread from host to other person so the close contact with pregnant and immunosuppressed person should be avoided for 2-3 weeks.
· The facility which is giving vaccination should be readily equipped with skilled personnel and drugs to manage anaphylaxis reaction.
· The contact of spirits and sterilizers should be avoided to the vials.
· The spirit applied before injection to skin should be completely evaporated.
· Live attenuated vaccine is not recommended during epidemic seasons.
· Use the vaccine as soon as possible after reconstitution.
· Do not administer the vaccine in case of incomplete dissolution, cracked vial and if label is not clear.
· The patient should be observed for any allergic reaction for at least 30 minutes after injection.