1 00:00:01,920 --> 00:00:06,440 Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey 2 00:00:06,519 --> 00:00:10,680 Speaker 1: brain Stuff, Lauren Volga bam here. Every fall, the seasonal 3 00:00:10,720 --> 00:00:15,040 Speaker 1: flu rears its ugly head. In twenty nineteen, about thirty 4 00:00:15,080 --> 00:00:17,680 Speaker 1: eight million people in the United States alone got sick 5 00:00:17,720 --> 00:00:20,880 Speaker 1: with the flu, and twenty two thousand died. According to 6 00:00:20,920 --> 00:00:23,720 Speaker 1: these Centers for Disease Control and Prevention or c d C, 7 00:00:24,920 --> 00:00:27,240 Speaker 1: the best way to protect yourself from getting sick each 8 00:00:27,320 --> 00:00:30,120 Speaker 1: year is by getting one of that year's formulations of 9 00:00:30,160 --> 00:00:33,800 Speaker 1: the influenza vaccine, either the flu shot or the nasal 10 00:00:33,840 --> 00:00:38,159 Speaker 1: spray flu vaccine. But if you're allergic to eggs, you 11 00:00:38,240 --> 00:00:42,600 Speaker 1: might have been cautioned against it. But why eggs Well, 12 00:00:42,800 --> 00:00:45,640 Speaker 1: the most common way flu vaccines are made is via 13 00:00:45,720 --> 00:00:50,159 Speaker 1: an egg based manufacturing process. Basically, the way these vaccines 14 00:00:50,159 --> 00:00:53,720 Speaker 1: are made is that first scientists around the world work 15 00:00:53,800 --> 00:00:57,360 Speaker 1: together to identify which mutations or genetic strains of the 16 00:00:57,360 --> 00:01:00,160 Speaker 1: flu are likely to have the most impact in the 17 00:01:00,200 --> 00:01:04,400 Speaker 1: coming year. Then researchers use chicken eggs as a medium 18 00:01:04,520 --> 00:01:08,000 Speaker 1: in which to grow, or rather replicate, a whole bunch 19 00:01:08,160 --> 00:01:13,120 Speaker 1: of those viruses. This actually requires an extra step. We 20 00:01:13,200 --> 00:01:17,000 Speaker 1: see eggs are an inexpensive and effective medium for virus 21 00:01:17,040 --> 00:01:20,640 Speaker 1: replication in general, but most strains of the flu that 22 00:01:20,680 --> 00:01:24,080 Speaker 1: are potentially dangerous to humans aren't that good at growing 23 00:01:24,120 --> 00:01:28,200 Speaker 1: in eggs, and so researchers develop special strains of the 24 00:01:28,400 --> 00:01:34,400 Speaker 1: dangerous strains that are called candidate vaccine viruses, or cvvs. 25 00:01:34,400 --> 00:01:38,319 Speaker 1: Cvvs have a lot in common with the original danger strains, 26 00:01:38,360 --> 00:01:41,559 Speaker 1: but are also good at replicating inside of chicken eggs. 27 00:01:43,120 --> 00:01:46,880 Speaker 1: One way that scientists create cvvs is by injecting eggs 28 00:01:46,920 --> 00:01:49,440 Speaker 1: with both one of those strains of the flu identified 29 00:01:49,480 --> 00:01:52,840 Speaker 1: as potentially dangerous and also a strain that's good at 30 00:01:52,880 --> 00:01:55,920 Speaker 1: growing in eggs. The two strains will sort of mix 31 00:01:55,960 --> 00:01:59,800 Speaker 1: and match genetically, and the scientists can then select cvvs 32 00:02:00,120 --> 00:02:05,760 Speaker 1: have both properties. Once you have your CVV, scientists inject 33 00:02:05,840 --> 00:02:08,760 Speaker 1: them into new chicken eggs and leave them to incubate 34 00:02:08,800 --> 00:02:12,919 Speaker 1: for several days. This allows the virus to replicate. Then, 35 00:02:13,080 --> 00:02:15,920 Speaker 1: the fluid from the eggs containing the viruses is harvested 36 00:02:15,960 --> 00:02:20,720 Speaker 1: and processed and used to create vaccines. Because this fluid 37 00:02:20,720 --> 00:02:24,080 Speaker 1: from eggs is used in creating most flu vaccines, most 38 00:02:24,200 --> 00:02:27,120 Speaker 1: types of flu vaccines do contain a small amount of 39 00:02:27,160 --> 00:02:30,880 Speaker 1: egg protein, which may trigger an allergic response in people. 40 00:02:30,960 --> 00:02:36,240 Speaker 1: With egg allergies, So should people with egg allergies avoid 41 00:02:36,320 --> 00:02:41,400 Speaker 1: getting annual flu shots. Not necessarily. Here's how egg allergies 42 00:02:41,440 --> 00:02:44,680 Speaker 1: work in brief. When someone with an egg allergy gets 43 00:02:44,720 --> 00:02:47,920 Speaker 1: egg in their system, their immune system goes into attack 44 00:02:48,000 --> 00:02:50,720 Speaker 1: mode against the proteins in the white spand or the 45 00:02:50,800 --> 00:02:54,000 Speaker 1: yolks of the egg. Their immune system sends out a 46 00:02:54,000 --> 00:02:58,840 Speaker 1: barrage of compounds to defend itself. This battle between allergens 47 00:02:58,880 --> 00:03:04,200 Speaker 1: and your bodies. Defend compounds, most notably, histamine, triggers allergy symptoms, 48 00:03:04,480 --> 00:03:08,600 Speaker 1: which can range from a mild rash to life threatening anaphylaxis. 49 00:03:10,080 --> 00:03:12,880 Speaker 1: This doesn't mean that people with egg allergies shouldn't get 50 00:03:12,880 --> 00:03:16,040 Speaker 1: flu shots. The CDC now recommends that people with the 51 00:03:16,160 --> 00:03:19,880 Speaker 1: history of egg allergies, regardless of the severity, are okay 52 00:03:19,960 --> 00:03:25,080 Speaker 1: to receive any licensed, recommended, and age appropriate influenza vaccine. 53 00:03:26,000 --> 00:03:28,519 Speaker 1: This decision is based on studies of both the nasal 54 00:03:28,560 --> 00:03:31,520 Speaker 1: spray vaccine and the flu shot in people with and 55 00:03:31,600 --> 00:03:36,240 Speaker 1: without egg allergies. The rate of anaphylaxis after all vaccines 56 00:03:36,680 --> 00:03:39,760 Speaker 1: is one point three one per one million doses. Given 57 00:03:40,320 --> 00:03:44,400 Speaker 1: that's super low, the CDC does recommend the people with 58 00:03:44,440 --> 00:03:47,560 Speaker 1: a history of severe allergic reactions to eggs. That is, 59 00:03:47,600 --> 00:03:50,680 Speaker 1: anyone who has gotten anything more serious than hives from eggs. 60 00:03:50,880 --> 00:03:54,240 Speaker 1: Be vaccinated in a medical setting such as a hospital, clinic, 61 00:03:54,360 --> 00:03:58,360 Speaker 1: health department, or doctor's office by a healthcare provider trained 62 00:03:58,400 --> 00:04:02,200 Speaker 1: to recognize and manage an allergic response. Just as a precaution, 63 00:04:02,840 --> 00:04:04,480 Speaker 1: they'll keep an eye on you for about half an 64 00:04:04,520 --> 00:04:06,960 Speaker 1: hour just to make sure you don't have a negative reaction. 65 00:04:08,120 --> 00:04:10,280 Speaker 1: But the risk of a bad reaction to a flu 66 00:04:10,400 --> 00:04:13,600 Speaker 1: vaccine due to an egg allergy is so low, and 67 00:04:13,640 --> 00:04:16,839 Speaker 1: the benefits of having the vaccine and thus probably avoiding 68 00:04:16,880 --> 00:04:19,560 Speaker 1: getting sick or passing the disease onto people around you 69 00:04:19,680 --> 00:04:25,120 Speaker 1: are so high that experts recommend it anyway. Flu vaccines 70 00:04:25,200 --> 00:04:28,640 Speaker 1: made via an entirely different, non egg related process are 71 00:04:28,800 --> 00:04:31,840 Speaker 1: much more rare, but they do exist. If you're interested 72 00:04:31,880 --> 00:04:34,280 Speaker 1: in getting one of these, check with a healthcare provider 73 00:04:34,360 --> 00:04:42,520 Speaker 1: for potential availability. Today's episode is based on the article 74 00:04:42,680 --> 00:04:44,120 Speaker 1: can you get a flu shot if you have an 75 00:04:44,120 --> 00:04:46,479 Speaker 1: egg allergy? On how stuff works dot com, written by 76 00:04:46,520 --> 00:04:49,240 Speaker 1: Jennifer Walker. Journey brain Stuff is production of by Heart 77 00:04:49,320 --> 00:04:51,320 Speaker 1: Radio in partnership with how stuff works dot Com and 78 00:04:51,440 --> 00:04:54,839 Speaker 1: is produced by Tyler Clanang or more podcasts My Heart Radio, 79 00:04:55,000 --> 00:04:57,719 Speaker 1: visit the heart Radio app, Apple Podcasts, or wherever you 80 00:04:57,720 --> 00:05:08,080 Speaker 1: listen to your favorite shows.