Experts at St Mary's Hospital in London estimate that each year almost 6,000 children with egg allergies are safely given the measles, mumps and rubella (MMR) jab.
The Health Education Authority recommended in 1997 that parents of children who have had reactions to eggs should consult their doctor before the vaccination is given.
But Dr Gideon Lack at St Mary's paediatric allergy and immunology department said: "The vast majority of children can safely be given the vaccine regardless of whether they are allergic to eggs."
He added: "The MMR vaccine is as safe as any other vaccine, and children with an allergy to eggs must not have their vaccinations delayed."
Hospitals
The 1997 advice has led to children being given the immunisations in hospital unnecessarily, he said.
Children were more likely to have allergic reactions to gelatin and the antibiotic neomycin, both of which are found in the vaccine in greater quantities than egg cells.
The amount of egg needed to provoke a reaction is at least 100,000 times more than the level found in vaccine doses, the British Medical Journal reports.
Only children who have had a previous life-threatening reaction to eggs or who have an allergy and severe asthma could be at risk, Dr Lack said.
This small number of children should be vaccinated in hospital, he added.
UK immunisation guidelines recommend that children should receive two doses of the MMR vaccine, the first shortly after their first birthday and the second before starting school.
Uptake rates are 90% for the first dose and under 50% for the second dose.
The Royal College of Paediatrics and Child Health and the British Society of Allergy and Clinical Immunology have endorsed Dr Lack's recommendations.