Inactivated Influenza Vaccine
Indications
Inactivated Influenza Vaccine is used to help protect against flu (influenza), a viral infection of the nose, throat and lungs that can be serious in older people, young children, pregnant women and people with long-term illnesses. It is given every year because flu viruses change and protection fades. Most current vaccines are "quadrivalent", covering four flu strains chosen each season.
How It Works
The vaccine contains killed (inactivated) flu virus or parts of the virus, so it cannot cause flu. It trains the immune system to recognise the virus and make antibodies. If you are later exposed to flu, your body can fight it off faster. Protection develops about 2 weeks after vaccination.
Dosage and Administration
The vaccine is given by a doctor or nurse as an injection into the upper arm muscle (or thigh in young children), usually once a year before or during the flu season. Adults and children aged 9 years and over need one dose. Children from 6 months to under 9 years who have never had a flu vaccine usually need two doses at least 4 weeks apart. The schedule is set by the health professional.
Interactions
Medicines that weaken the immune system, such as Corticosteroids in high doses, chemotherapy or Ciclosporin, may reduce the response to the vaccine. It can usually be given at the same time as other vaccines, in a different arm. Tell the vaccinator if you take blood thinners such as Warfarin, as bruising may occur at the injection site.
Contraindications
Do not give to anyone who had a severe allergic reaction to a previous flu vaccine or to any vaccine ingredient (some vaccines contain traces of egg protein, formaldehyde or antibiotics such as Neomycin). Vaccination is postponed during an illness with high fever. It is not for babies under 6 months.
Side Effects
Common side effects include soreness, redness or swelling where the injection was given, mild fever, tiredness, headache and muscle aches, usually lasting 1 to 2 days. Rarely, it may cause allergic reactions or, very rarely, nerve conditions such as Guillain-Barré syndrome.
Get urgent medical help if you develop swelling of the face or throat, difficulty breathing, a fast heartbeat or dizziness shortly after the injection, or weakness or tingling in the legs that spreads upwards in the weeks afterwards.
Pregnancy and Lactation
The inactivated flu vaccine is recommended during pregnancy at any stage, as it protects the mother and also the baby in its first months. It is safe during breastfeeding.
Precautions and Warnings
Tell the health professional if you have a bleeding disorder, a weak immune system, had Guillain-Barré syndrome after a previous flu vaccine, or have fainted after injections. The vaccine does not protect against colds or other viruses, and no vaccine gives complete protection.
Overdose
Overdose is unlikely because the vaccine is given by health professionals in single doses. An extra dose is not expected to cause serious harm.
Therapeutic Class
Vaccine (inactivated viral vaccine).
Storage
Store in a refrigerator at 2 to 8°C in the original pack to protect from light. Do not freeze; discard if it has been frozen.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.
All brands of Inactivated Influenza Vaccine