Why is allergy to eggs a contraindication to getting some vaccines?
Some vaccines, including the majority of vaccines against influenza, are cultured in chicken eggs. During the process of creating the vaccine, the majority of the egg protein is removed, but there is some concern that these vaccines might generate an allergic reaction in individuals with an egg allergy.
A recent report found that the majority of children with egg allergies who were given a flu shot had no adverse reactions; about 5% of children in the studied group developed relatively minor reactions such as hives, the majority of which resolved without treatment. Additional research is underway to study this issue further.
In most cases, only people with a severe (life-threatening) allergy to eggs are recommended against receiving egg-based vaccines. Your doctor can provide specific information.
Do vaccines cause autism?
No. Vaccines do not cause autism. This possibility was publicized after a 1998 paper by a British physician who claimed to have found evidence that the MMR (measles, mumps and rubella) vaccine was linked to autism. The potential link has been thoroughly explored; study after study has found no such link, and the original 1998 study has been formally withdrawn by The Lancet, which had originally published it. Studies were also done regarding the possibility of a link between the preservative thimerosal, which is used in some vaccines, and autism; again, no such link was found.
It’s likely that this misconception persists because of the coincidence of timing between early childhood vaccinations and the first appearance of symptoms of autism.