VIT (also known as desensitisation) can help to decrease how severe an insect allergy is over time. VIT has been shown to be an effective treatment for severe allergies to bee, wasp and some ant stings. Knowing the type of insect that caused the reaction is important as it can help decide if VIT is right for you.
The treatment involves having injections under the skin (subcutaneous) of very small amounts of specially processed insect venom to help a person’s immune system become less reactive to that type of insect. The treatment takes at least 3-5 years and requires monthly visits (on average) to a health professional to have the injections. Although VIT can provide some protection early in treatment, continuing for the recommended time is more effective and helps the protection last longer after the injections are stopped.
What VIT is available in Australia?
Speak with your doctor if you are interested in VIT. They will be able to provide you with more information about VIT.
Government subsidies are available for VIT to bees and wasps on the Pharmaceutical Benefits Scheme (PBS) making it more affordable. VIT for Jack Jumper Ant allergy is available in some areas of Australia.
The process
VIT is prescribed and started under the care of an allergy specialist but can be continued at your local medical centre. Before you start, your allergy specialist should explain the treatment to you and get your consent. If you agree, there is protocol to be followed and your specialist may give you an ASCIA Treatment Plan to give to your local doctor so you can continue your treatment with them.
VIT involves a small injection under the skin which may be given by the doctor or a nurse.
Treatment consists of 2 phases:
- Initiation (starting) phase: injections of increasing doses of venom given (often in hospital) under the guidance of an allergy specialist until the right dose of venom has been reached.
- Maintenance (ongoing) phase: regular injections (usually given monthly) of a constant dose, either given in hospital or in general practice by your GP.
It is important that people see their allergy specialist regularly during VIT treatment. Stopping too early can mean the effectiveness of the treatment does not last as long.
At least one adrenaline (epinephrine) device should be carried when on VIT and thereafter unless your doctor advises it is safe for you to stop having an adrenaline device easily accessible at all times.
Who should consider VIT?
People who have a history of anaphylaxis to Jack Jumper ant, bee or wasp stings should speak to an allergy specialist about VIT.
People who have had a rash all over their body but no signs of anaphylaxis after an insect sting should see an allergy specialist. VIT is sometimes considered for adults, but not usually children, who have had this type of allergic reaction.
VIT is not used for people who have only had large localised reactions to insect sting (swelling/rash around the sting) without any other signs or symptoms.
How effective and safe is VIT?
There are risks associated with VIT just as there are risks with not having VIT if you are at risk of anaphylaxis to an insect sting. Discuss the risks with your allergy specialist.
During VIT, there is a small risk that people will have anaphylaxis after they have had their injection. This is why VIT is done in a medical setting. People should stay for about 45-60 minutes after their VIT injection in case they have a severe allergic reaction.
Most people on VIT are likely to be protected from dangerous reactions to stings while they continue maintenance therapy. There is still some risk (5 to 20%) of a severe allergic reaction to a sting during maintenance VIT but reactions are usually not as severe as they were before treatment. Once a course of VIT is completed there is less than a 10% chance of a severe allergic reaction occurring.
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