Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey
Speaker 1: brain Stuff, Lauren Volga bam here. Every fall, the seasonal
Speaker 1: flu rears its ugly head. In twenty nineteen, about thirty
Speaker 1: eight million people in the United States alone got sick
Speaker 1: with the flu, and twenty two thousand died. According to
Speaker 1: these Centers for Disease Control and Prevention or c d C,
Speaker 1: the best way to protect yourself from getting sick each
Speaker 1: year is by getting one of that year's formulations of
Speaker 1: the influenza vaccine, either the flu shot or the nasal
Speaker 1: spray flu vaccine. But if you're allergic to eggs, you
Speaker 1: might have been cautioned against it. But why eggs Well,
Speaker 1: the most common way flu vaccines are made is via
Speaker 1: an egg based manufacturing process. Basically, the way these vaccines
Speaker 1: are made is that first scientists around the world work
Speaker 1: together to identify which mutations or genetic strains of the
Speaker 1: flu are likely to have the most impact in the
Speaker 1: coming year. Then researchers use chicken eggs as a medium
Speaker 1: in which to grow, or rather replicate, a whole bunch
Speaker 1: of those viruses. This actually requires an extra step. We
Speaker 1: see eggs are an inexpensive and effective medium for virus
Speaker 1: replication in general, but most strains of the flu that
Speaker 1: are potentially dangerous to humans aren't that good at growing
Speaker 1: in eggs, and so researchers develop special strains of the
Speaker 1: dangerous strains that are called candidate vaccine viruses, or cvvs.
Speaker 1: Cvvs have a lot in common with the original danger strains,
Speaker 1: but are also good at replicating inside of chicken eggs.
Speaker 1: One way that scientists create cvvs is by injecting eggs
Speaker 1: with both one of those strains of the flu identified
Speaker 1: as potentially dangerous and also a strain that's good at
Speaker 1: growing in eggs. The two strains will sort of mix
Speaker 1: and match genetically, and the scientists can then select cvvs
Speaker 1: have both properties. Once you have your CVV, scientists inject
Speaker 1: them into new chicken eggs and leave them to incubate
Speaker 1: for several days. This allows the virus to replicate. Then,
Speaker 1: the fluid from the eggs containing the viruses is harvested
Speaker 1: and processed and used to create vaccines. Because this fluid
Speaker 1: from eggs is used in creating most flu vaccines, most
Speaker 1: types of flu vaccines do contain a small amount of
Speaker 1: egg protein, which may trigger an allergic response in people.
Speaker 1: With egg allergies, So should people with egg allergies avoid
Speaker 1: getting annual flu shots. Not necessarily. Here's how egg allergies
Speaker 1: work in brief. When someone with an egg allergy gets
Speaker 1: egg in their system, their immune system goes into attack
Speaker 1: mode against the proteins in the white spand or the
Speaker 1: yolks of the egg. Their immune system sends out a
Speaker 1: barrage of compounds to defend itself. This battle between allergens
Speaker 1: and your bodies. Defend compounds, most notably, histamine, triggers allergy symptoms,
Speaker 1: which can range from a mild rash to life threatening anaphylaxis.
Speaker 1: This doesn't mean that people with egg allergies shouldn't get
Speaker 1: flu shots. The CDC now recommends that people with the
Speaker 1: history of egg allergies, regardless of the severity, are okay
Speaker 1: to receive any licensed, recommended, and age appropriate influenza vaccine.
Speaker 1: This decision is based on studies of both the nasal
Speaker 1: spray vaccine and the flu shot in people with and
Speaker 1: without egg allergies. The rate of anaphylaxis after all vaccines
Speaker 1: is one point three one per one million doses. Given
Speaker 1: that's super low, the CDC does recommend the people with
Speaker 1: a history of severe allergic reactions to eggs. That is,
Speaker 1: anyone who has gotten anything more serious than hives from eggs.
Speaker 1: Be vaccinated in a medical setting such as a hospital, clinic,
Speaker 1: health department, or doctor's office by a healthcare provider trained
Speaker 1: to recognize and manage an allergic response. Just as a precaution,
Speaker 1: they'll keep an eye on you for about half an
Speaker 1: hour just to make sure you don't have a negative reaction.
Speaker 1: But the risk of a bad reaction to a flu
Speaker 1: vaccine due to an egg allergy is so low, and
Speaker 1: the benefits of having the vaccine and thus probably avoiding
Speaker 1: getting sick or passing the disease onto people around you
Speaker 1: are so high that experts recommend it anyway. Flu vaccines
Speaker 1: made via an entirely different, non egg related process are
Speaker 1: much more rare, but they do exist. If you're interested
Speaker 1: in getting one of these, check with a healthcare provider
Speaker 1: for potential availability. Today's episode is based on the article
Speaker 1: can you get a flu shot if you have an
Speaker 1: egg allergy? On how stuff works dot com, written by
Speaker 1: Jennifer Walker. Journey brain Stuff is production of by Heart
Speaker 1: Radio in partnership with how stuff works dot Com and
Speaker 1: is produced by Tyler Clanang or more podcasts My Heart Radio,
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