Swine Flu and Allergy
Patients with allergies, intolerances and chemical sensitivity often need to take their sensitivities into account when considering medications or vaccinations. With this in mind, the following information may be helpful.
Swine flu is currently a mild illness in most people, no more severe than a bad cold or the usual winter flu virus. As with any cold or flu, patients with other health problems may be affected more severely, and a very small proportion may suffer severe or even fatal illness. However in general the main problem is not the severity of the virus, but the fact that many more people than usual will catch it.
Allergy patients and chemical sensitivity sufferers are not necessarily at more risk of catching Swine Flu. It is immunosuppressed patients (e.g. those with known immune deficiency illness or on chemotherapy etc) who may be more at risk.
If you are worried that you may have Swine Flu, you should contact the National Flu Pandemic Helpline or NHS Direct.
Anti-flu drugs and allergy
The main drug used in the treatment of swine-flu is Tamiflu (oseltamivir ). There have been very few reports of true allergy to Tamiflu. Because of the sort of drug it is, and the way that it is carried and handled in the body, allergy would not be likely (although of course it can never be ruled out).
Tamiflu capsules are made of gelatine and are coloured with natural iron and titanium oxides rather than artificial colourings. They are coated with natural shellac, although there is a small amount of printing ink on each capsule. Patients who have problems with the capsule can open them, tip the powder onto food and take the drug without the capsule, although this should not be done routinely. The powder contains corn starch and other generally inert ingredients such as talc and povidone.
Tamiflu powder is available for children, but as this contains saccharin, sodium benzoate and tutti-frutti flavouring, it is not suitable as an alternative for adults who have problems with capsules. Opening the capsule is a better alternative.
As far as chemical sensitivity is concerned, this drug does not use the common detoxification pathways and has little chemical interaction with the body so it probably won't cause too many problems (although, of course, chemical sensitivity sufferers are often affected in some way by many medications).
The other drug that may be used is Relenza (zanamivir). This is given in the form of powder for inhalation (in a device similar to some types of asthma inhalers).
There have been very rare reports of allergy-type reactions from Relenza, including wheezing and rashes. The powder also contains lactose (milk powder).
Only about 20% of the drug is absorbed in to the general circulation and it is excreted unchanged (i.e. it does not go through the usual detoxification pathways) so it should not cause too much of a problem for chemically-sensitive patients.
Flu vaccination
As with the usual flu vaccines, Swine Flu vaccines are mostly egg-based. The existing guidelines for the use of egg-based vaccines state that patients who can tolerate moderate amounts of egg in their diet can be given the vaccine, but patients who are severely egg allergic (anaphylactic) should not be given egg-based flu vaccines. The potential risks and benefits should be worked out and discussed in each individual case. In the rare event that it is decided to give a severely egg-allergic patient an egg-based flu vaccine, this should be done in hospital.
Some flu vaccines are produced which are not egg-based. For Swine Flu, the two vaccines in use are Pandemrix (GSK) which is egg-based, and Celvapan (Baxter) which is cell-cultured and egg-free. Celvapan is therefore suitable for use in egg-allergic patients. 49,000 doses of Celvapan are being made available which should be sufficient to meet demand, but by far the largest number of vaccines will be the egg-based Pandemrix.
If you suffer severe egg allergy and are offered Swine Flu vaccination, make sure that the vaccine you are being given is Celvapan (egg-free) and not Pandemrix which is egg-based.
Note that for 'ordinary' seasonal flu, there is no egg-free vaccine available this year. All seasonal flu vaccine will be egg-based and will not be suitable for egg-allergic patients.
If you are unable to get egg-free vaccine, remember that you will still be able to take anti-viral drugs if you should develop symptoms. Vaccination is as much about developing “herd immunity” as about protecting individuals and it is important that as many people as possible are vaccinated. However most studies show that normal flu vaccination does not make much difference to whether an individual asthmatic gets flu-related asthma. If most people are vaccinated then there is less chance of catching the virus, even if you yourself have not been vaccinated.
None of the information here is intended to replace a discussion with your GP or Specialist about your own health problems. See your Doctor if you are concerned about vaccination or about using anti-flu drugs.
Author: John Collard, Clinical Director, Allergy UK - July 2009
