The concern about receiving a flu shot when you have an egg allergy is common, as many people have heard that the vaccine contains egg proteins. Annual influenza vaccination is an important health measure for nearly everyone six months of age and older. Medical science and public health recommendations have evolved significantly, and an egg allergy is rarely a barrier to getting vaccinated today. This shift is due to a better understanding of the minimal risk and the development of new, alternative vaccine production methods.
Understanding the Historical Connection Between Eggs and Flu Vaccines
For decades, the standard method for producing influenza vaccines relied on using fertilized chicken eggs as a growth medium for the vaccine viruses. This process begins by injecting a sample of the flu virus into the egg, where the virus replicates rapidly. After incubation, the fluid containing the virus is harvested.
This traditional method resulted in trace amounts of egg protein, specifically ovalbumin, remaining in the final vaccine product. Historically, this residual protein was the source of concern for people with known egg allergies. Purification techniques have always worked to reduce this ovalbumin content, but the presence of any egg component caused caution among healthcare providers.
The amount of ovalbumin in modern, egg-based vaccines is extremely low, generally less than 1 microgram per dose. This small quantity is a fraction of the amount needed to trigger an allergic reaction in most egg-allergic individuals. The risk of anaphylaxis from the flu shot is exceedingly rare, even for those with egg allergies.
Current Safety Recommendations for Egg Allergy Sufferers
Current medical guidelines state that people with an egg allergy, regardless of the severity of their previous reaction, can receive any licensed flu vaccine appropriate for their age and health status. This guidance applies to both egg-based and non-egg-based vaccines. The purification process for standard flu shots is so effective that the amount of ovalbumin is considered negligible.
Individuals who have experienced only hives after exposure to eggs can receive any flu vaccine without special precautions. The risk of a severe allergic reaction is extremely low, similar to the general population. The overall rate of anaphylaxis following any vaccination, including the flu shot, is approximately 1.31 to 1.35 cases per one million doses administered.
Even for those who have experienced a severe allergic reaction to eggs, such as anaphylaxis, no additional safety measures are recommended beyond those for any vaccine recipient. All vaccinations should occur in a setting where personnel and equipment are available to manage a rapid allergic reaction, which is standard practice. Previously, guidelines recommended observation periods or administration by an allergist, but these extra measures are no longer considered necessary solely due to an egg allergy. The only exception is a person who has had a severe allergic reaction to a previous dose of any flu vaccine or one of its components.
Alternative Egg-Free Flu Vaccine Options
For patients and providers who prefer an option with no egg protein, two types of flu vaccines are manufactured using egg-free technology. These alternatives eliminate the historical concern of residual ovalbumin entirely.
One alternative is the recombinant influenza vaccine, manufactured using recombinant technology without requiring the flu virus or chicken eggs. This vaccine, often known as Flublok, is created synthetically by isolating the genetic material for the surface protein, hemagglutinin, and growing it in cultured insect cells. This process avoids the use of eggs entirely, making it a safe option for those with severe allergies. Flublok is currently licensed for use in adults aged 18 years and older.
Another egg-free option is the cell-culture-based influenza vaccine, known as Flucelvax. Instead of using chicken eggs, this vaccine grows the flu viruses in cultured cells of mammalian origin. Since the process does not involve hen’s eggs, it is considered egg-free and is licensed for use in people six months of age and older. Consulting with a healthcare provider is the best way to determine the most appropriate vaccine choice based on individual health history.