Among the allergy community, there is a lot of doubt and uncertainty about the safety of the MMR vaccine in egg allergic children. This post sums up the latest research and recommendations.
What is the MMR?
The MMR Vaccine protects from measles, mumps and rubella. It is given around 12 month of age and again around 3 to 5 years of age. It is an active virus, consisting of weakened forms of the viruses.
Why is there a concern about giving the vaccine to egg allergic children?
The vaccine is cultured on embryo chick fibroblasts.
Though, it does not contain any hen’s egg protein. If traces of hen’s egg protein are detected, they are highly processed and their concentration is very low.
a danish study published in 2013, investigating 32 children with egg allergy who had been referred to get their mmr vaccination (Priorix MMR) at hospital. None of the children had severe reactions
Published in September last year, the authors claim their study being “one of the largest studies looking at childhood vaccinations performed in a hospital setting for children who are ‘at risk’ of allergy, anaphylaxis or hypersensitivity”. A total of 374 patients (with a medical history of anaphylaxis, allergic reaction or strong suspicion of a severe adverse reaction against egg) contributed to the findings. All of the children received their vaccinations in a hospital setting. “Only six patients (1.3%) experienced an immediate reaction to a vaccination. All reactions were minor”. The authors conclude that “A significant number of referrals were unwarranted and the majority could have been safely managed in the community”.
Latest expert opinion (BSACI, 2007):
The MMR has an excellent safety-record and may be administered to all egg-allergic children in a primary care setting. As with any other immunisation, adrenaline should be readily available in case of rare and unpredictable anaphylaxis. MMR should be postponed if child is unwell. A hospital based application is necessary after a previous severe reaction to a vaccination (MMR or other) after a specialist assessment. It might be possible that the reaction occured due to an allergy to other components of the shot (gelatine (beef and lamb allergy) or antibiotics (neomycin or other)).
Other vaccinations and egg allergy:
Flu vaccine: updated every year, the content level of ovalbumin, varies every year, some jabs do not contain egg. A split dose (1/10 of single dose, than 9/10 of dose) of the vaccine might be an option. Consult your GP or specialist for up to date advise.
Yellow fever vaccine: unsuitable for children with egg allergy
So what is the verdict?
Latest research suggests that the likelihood for an egg-allergic child to react to the MMR vaccine is about the same as to any other non-egg containing vaccine. Reactions are rare but non predictable due to other substances like gelatine and antibiotics.
Even though the MMR seems to be a safe shot, it is always recommended to seek advise from your specialist if in any doubt. Every child reacts differently and the risk profile of your allergic child can be best assessed by your trusted allergist.
Sources: the anaphylaxis campaign, nhs choices, pubmed, bupa, bsaci
Please note that this post does not imply any medical advise. Please always consult your specialist.