Articles, Blog

The Trouble with This Year’s Flu Season

November 5, 2019

[INTRO ♪] If you’re feeling under the weather—tired,
achy, with a cough or runny nose; possibly feverish—well, first of all,
I hope you feel better soon because that sucks. But if it’s more than a cold, you might
have influenza, or the flu. And even if you’re feeling fine, there’s
a good chance you know someone who isn’t. Flu season is picking up steam, and it’s
turning out to be a pretty bad year for North America—
especially in the US. And as of the first week of January,
flu was widespread in virtually every part of the US,
along with some parts of southern Canada. In the United States, some 23 out of every
100,000 people had been hospitalized for the disease. That’s nearly twice what it was the week
before, and three-quarters of the way to the number
of cases three years ago, which was one of the worst flu seasons in
recent memory. But why is this year any worse than normal? The simple answer is that more than 80% of
the flu viruses making the rounds, at least in the US, are
a subtype called H3N2. And in the flu world, H3N2 is a baddie. These viruses tend to not only make more people sick, but to make more of them very sick,
which means more hospitalizations and deaths. Researchers don’t have everything entirely
figured out, but they do know that there are at least a
couple of reasons for this. The first has to do with the fact that H3N2 viruses are tricky to vaccinate against. You might know that flu viruses come in a
few different main flavors, named A, B, C, or D.
‘A’ and ‘B’ are the ones we encounter with seasonal flu,
and influenza A viruses are further broken down by
the kind of proteins on their surface. The ‘H’ stands for hemagglutinin, and
the N is for neuraminidase. Each type of these proteins gets a number,
like H1 or N2. Since the proteins are on the outside of the
virus, they’re what your immune cells see and respond
to if you get infected. But for that very same reason, if flu viruses
mutate, changing what these proteins look like,
the virus can escape your immune response and get off scot-free. This is called antigenic drift, and it’s
why you need a new vaccine every year. Since flu viruses are changing all the time,
scientists have to make an educated guess as to which specific viruses
are likely to circulate in a given season, and then make a seasonal flu shot
that will protect against those three or four strains. In the case of H3N2, this is especially hard
to do because those viruses mutate even more quickly
than their cousins. That means there’s a higher chance that
in the six months or so between when the scientists choose the strains
in their vaccine and when flu season starts, the virus could
have changed. It mutates so quickly that the virus can even
shift during the flu season. A second complication is that in recent years,
the H3N2 viruses we’ve wanted to vaccinate against are ones that don’t grow very well in chicken eggs. That becomes a problem because almost all
flu shots are made by growing lots of virus in eggs. And to grow well, the virus can mutate to
adapt to chicken cells. That’s all fine and dandy if it’s not
a part of the virus that matters. But if the mutation changes one of those main
surface proteins, like hemagglutinin, it could make the vaccine
much less effective. This appears to have been what happened last
season, and it’s almost certainly the case this
year as well. Researchers were puzzled because last season’s
H3N2 strain was well-matched, but that part of the vaccine
was only about 30-35% effective. Virologists looking at the issue realized
that the hemagglutinin protein that ended up in the vaccine was missing an
important spot on it that had a sugar attached. That change made it easier for the virus to
infect chicken cells, but it no longer looked as much like the virus
that was infecting people. So the antibodies people made in response
to the vaccine weren’t as good at clearing out the real
virus. The other unfortunate aspect of H3N2 viruses
is that they take an especially heavy toll on the elderly. Flu is usually worse for older people. They’re often frail, or sick with other
things, and their immune systems simply aren’t as
robust. But H3N2 viruses take this to the extreme. And researchers have a pretty interesting
idea for why that is, although it hasn’t been proven. It’s called original antigenic sin, or imprinting,
and the idea is that how well you respond to the flu
depends on which flu viruses your immune system sees first. Whatever you were first exposed to as a kid,
your immune system knows super well and can handle with relative ease. Less so with later strains. They might look enough like the ones you were
exposed to earlier in life to trigger the same response, but because
the virus is different, it’s not as good a defense. The first H3N2 virus reared its ugly head
around 1968, so people over the age of about 50 didn’t
grow up seeing these viruses. That could mean their immune systems are really
better suited to fight off different types of flu, and explain
why they’re more susceptible to H3N2 viruses now. So, with H3N2, you have a flu subtype that’s
potentially more deadly, simply because of timing and age, and a vaccine
that’s less effective. But the takeaway here should not be to skip
your flu shot if you haven’t gotten it yet, especially
since flu season is nowhere near over. It usually peaks around February and doesn’t
end until May. The vaccine still protects against other types
of flu, which are also circulating. And even reduced effectiveness is better than
no effectiveness, especially if you’re at risk, because it
can mean if you do get sick, it won’t be as bad. By getting vaccinated, you will also protect
those around you through what’s known as herd immunity. If enough people have even partial protection,
that can cut down on the total amount of flu going around
and make it less likely that people who can’t get the shot will catch it,
like infants and those with weakened immune systems. So, even if you feel like you particularly
don’t need the flu shot for yourself, think about the fact that you will become
a vector who may infect someone who can’t get that
protection. So go get jabbed! And you know who else does good things for people around them? Our President of Space Matthew Brant! Matthew and the rest of our patrons on Patreon
make sure that SciShow is free for everyone … except themselves. So thank you, Matthew, for supporting SciShow! [OUTRO ♪]


  • Reply vf fa February 4, 2018 at 8:52 pm

    Recovering this week … It's so annoying. I haven't been sick for a few years now, but this one got me.

  • Reply Gina C February 5, 2018 at 3:13 am

    For people saying "I've never gotten the shot or the flu" that's because of herd immunity AKA everyone else around you getting the shot to decrease its spread. All you're doing is hurting yourself by not even attempting to build an immunity by not getting one. If you can get one, do. It's worth it. Even if you don't bother getting one every year, get one every now and then to help yourself and those around you.

  • Reply onelastchance February 5, 2018 at 12:07 pm

    Never will I get a flu shot.

  • Reply Zeldon567 February 5, 2018 at 10:18 pm

    The antivaxer purge has begun.

  • Reply Diane Bingham February 6, 2018 at 3:53 pm

    By the labs created the flu strains and then having them injected it is causing more outbreaks due to flu strains mutating and for survival. The big flu epidemic of 1918, was caused by filthy conditions and transport of chinese laborers in sealed train compartments, during the war. It was spread by disease and death in the trenches in France and other countries. If we stop tampering with nature and follow sound health practices, we will be much better off.

  • Reply Jess S. February 7, 2018 at 5:13 am

    I have to rely off herd immunity, I have too poor of an immune system that any flu shot I get makes me sick.

  • Reply silviu ciortan February 7, 2018 at 12:14 pm

    A…..a new vaccine every year? Oh…….

  • Reply Lava T February 7, 2018 at 11:16 pm

    My school is closed for the rest of the week

  • Reply Jassy Alzen February 7, 2018 at 11:48 pm

    I had gotten my flu shot in September and I got the flu anyways

  • Reply Tom Crenshaw February 8, 2018 at 12:46 am

    Wash your hands

  • Reply Tom Crenshaw February 8, 2018 at 12:49 am

    I was once at Dave and busters, saw two people go straight from the bathroom stall to the game floor. WASH YOUR HANDS

  • Reply Danae Christodoulou February 8, 2018 at 1:33 pm

    Why do people complain?

  • Reply Lillian Swaim February 8, 2018 at 2:41 pm

    'hospitalized' is the way that most people think of when they hear that word? or just like, going to an urgent care to get swabbed?

  • Reply Siouxie Q February 8, 2018 at 7:03 pm

    I read an article that says Native Americans are considered in the "High Risk" zone for susceptibility to the flu. The article did not explain why we are. Thoughts? (Braces for racist comments)

  • Reply Roy Orbison February 9, 2018 at 6:20 am

    I blame it on dumbass people who have the flu but really wanted to go to Walmart anyway

  • Reply troryANCAS February 9, 2018 at 11:41 am

    Are flu shots free tho

  • Reply Lærke Nielsen February 9, 2018 at 1:45 pm

    4:50 that’s why there were only 10 in school today when we normally are 23 students

  • Reply Kyra Smith February 9, 2018 at 2:12 pm

    I get sick every year, this year, nothing lol

  • Reply trancestimuli February 9, 2018 at 4:11 pm

    My daughter and I got H5N1 about 7 years ago. That was freaking terrible. Worst flu I've ever had

  • Reply Enif E February 9, 2018 at 9:04 pm


  • Reply Robert Evans February 9, 2018 at 9:07 pm

    Fe-BU-ary??? Is that anything like Feb-RU-ary??  February! Come on people, quit mispronouncing this month.

  • Reply Robert Tanksley February 10, 2018 at 6:00 am

    30 years old and never had flu… Probably kill me if I ever do.

  • Reply Elizabeth Shaw February 10, 2018 at 10:25 am

    I had the flu 3 years ago and it was horrid! I haven't had a flu shot this year and I am disabled medically and physically. The only family or friend I have is my mother who keeps screaming at me people are dying but I don't know how I'm supposed to get out of the house for a flu shot she won't take me. She's 85 and drives herself everywhere but won't take me 2 miles to get a flu shot.

  • Reply Elizabeth Shaw February 10, 2018 at 10:26 am

    What is the efficacy of a vegan food shot?

  • Reply CrpL February 10, 2018 at 2:45 pm

    I have it rn ????

  • Reply Shenro February 10, 2018 at 2:58 pm

    a flu shot once a year? lol i don't know if i've ever even had a flu shot.

  • Reply MikeTheMysterious February 10, 2018 at 3:20 pm

    Hm…. i had the flu but its gone now

  • Reply MikeTheMysterious February 10, 2018 at 3:20 pm

    My immune system is so powerful its ridiculous

  • Reply Bob Silver February 10, 2018 at 3:44 pm

    Flu vaccines don't work, because the virus has changed since they made the vaccine.

  • Reply girls pretty February 10, 2018 at 4:37 pm

    Vaccines are so important! I got sick with pertussis, despite being fully vaccinated. I've been battling it for months, and I'm pretty much better from it now. The thing is, it wasn't as bad as regular pertussis because partial immunity. If I had 0 immunity to pertussis, I probably wouldn't be alive to type this comment.

  • Reply Pitaya February 10, 2018 at 6:03 pm

    This was the first time I actually started constantly washingy hands and eating healthy because I really don't want the flu

  • Reply James Beech February 10, 2018 at 7:22 pm

    What happened to SR Foxley? Are they okay?

  • Reply Rebekah VanLaarhoven February 11, 2018 at 2:08 am

    I have never gotten the flu shot…. oh well

  • Reply CTokyo X February 11, 2018 at 2:42 am

    I have the flu rn fml I feel miserable and weak and I’ve been missing school now ?

  • Reply RareDiamondXD 2 February 11, 2018 at 5:27 am

    Well I have h3n2 flu and it ain’t comfy

  • Reply Liz Torres February 12, 2018 at 2:12 pm

    So these vaccines are super innefective.. but you still say to go get them? What?

  • Reply Orion.theMetalhead_ 16 February 12, 2018 at 9:56 pm

    Wait, you can die from the flu? Why haven't I heard this earlier?

  • Reply Brenda Randolph February 12, 2018 at 9:59 pm

    I am so sick ? 104.5 right now

  • Reply luigidaman1 February 13, 2018 at 12:16 am

    Uhoh Aids 2.0

  • Reply Anonymous February 13, 2018 at 3:03 am

    Staph Pneumonia Outbreak?

  • Reply Ruru Asile February 13, 2018 at 3:37 am

    Hmmmm is it time to order my dr.plague costume now ???????

  • Reply David Shipley February 13, 2018 at 2:00 pm

    I remember seeing a video where you where talking about research that could potentially create a vaccine against all types of flu: how is that coming along?

  • Reply MzClementine February 13, 2018 at 2:06 pm

    Logic! Stop vaccines for the flu! ?

  • Reply For me to live is Christ To die is gain February 13, 2018 at 4:23 pm

    Who is watching this while being sick?

  • Reply Titanic February 14, 2018 at 3:08 am

    My sister has been sick for about 2 to 3 weeks now, and is not getting that much better.

  • Reply SadlynotCastiel X February 16, 2018 at 11:45 am

    Of course I get the flu when I get the shot, I haven't gotten the shot for the past 2 years and never got it. Hopefully I'll be okay. I have Strain B. I also have to use my inhaler that I haven't used in about 4 years, but now I can't breathe very well.

  • Reply Jenny Lee February 16, 2018 at 2:47 pm

    I had the flu in '68; it was pretty horrible-what I remember of it. There were hallucinations and a really high fever, I don't remember being sore all over like the flu I had in '77. '77 was very bad because our baby was just about 2 months old and I could hardly get myself off the couch to go to the bathroom.
    The flu isn't like a bad cold, It can be deadly.

  • Reply Victoria Anne February 17, 2018 at 12:26 am

    Feverish in Southern Canada ?

  • Reply Victor Hensel-Coe February 17, 2018 at 5:23 pm

    I I have a question- why do I miss out words in sentences when I type?

  • Reply Nick M February 17, 2018 at 9:32 pm

    I’m sick as a dog

  • Reply T.F.G February 18, 2018 at 7:35 pm

    When does it end?

  • Reply Tiny Pastel Mia February 19, 2018 at 3:25 am

    This is why I and my family are dead……I am dead very dead

  • Reply TorroDash February 21, 2018 at 1:31 pm

    * f l u*

  • Reply C.I.A. February 23, 2018 at 4:02 am

    I had the flu last year in October. I took no medication, I just drank plenty of liquids, ate really healthy and drink power juices and antioxidants non stop, sure it was the worst 4 days of my life, but after that, I was fine. Never got the 2017-18 flu again.

  • Reply Ride The Lightning February 23, 2018 at 8:15 am

    A case of gastroenteritis I have never had before. Usually I just throw up alot and that is it, this time around I am constantly wiping my nose, coughing non stop, I get a fever that comes anf goes along with cold chills at the same time, feels like I am getting better but then I feel nauseated again. It is like the regular flu mixed with gastroenteritis at the same time

  • Reply R P February 23, 2018 at 8:19 pm

    Ill get a shot anyway but I will NEVER get the nasal spray. I never get sick with a shot but every single time I had the spray I got terribly sick. I could tell I was going to get sick after the spray because I would get a migraine an hour later and then the next day I’d have a cough, sore throat, runny nose and feel disgusting.

  • Reply Alexis Harper February 25, 2018 at 7:36 pm

    I like getting jabbed with needles. As long as I get to do it. I don’t like when someone else does it, but am really obsessive about giving them to myself.

  • Reply Overdose On Coffee February 26, 2018 at 2:48 am

    thank you for the info!

  • Reply ovmium February 26, 2018 at 11:25 pm

    The doctor said I had h3n2 last year does that mean I’m resistant to it

  • Reply Gaming4Justice February 27, 2018 at 11:02 am

    I love how I haven't had a single day when I was sick this winter.

  • Reply IW Nunn February 27, 2018 at 6:17 pm

    Up your vit d intake. Very few people get enough d from the sun during the winter

  • Reply ¡Ricola! February 28, 2018 at 4:17 am

    I’m allergic to the Flu vaccine

  • Reply steel king March 1, 2018 at 4:42 am

    past couple years i havent gotten sick always got sick when i got the shot so up yours dumbass

  • Reply Karen Southworth March 1, 2018 at 11:21 pm

    I think I have the flu?????????

  • Reply zaksor parkour March 3, 2018 at 10:01 am

    I bet it can't get to Greenland

  • Reply William Morrison March 4, 2018 at 10:54 pm

    What if the 2018 H3N2 virus was manufactured and deliberately spread as a North Korean bio-attack?

  • Reply Melanie Kiwi March 6, 2018 at 12:55 am

    Had two bloody nose, sore throat, And a headache…. today and yesterday… ??

  • Reply Peony March 6, 2018 at 7:22 am

    I’ve never had a flu shot- really only the vulnerable in my country get it. But I’ve also had all the super scary ones that killed people in other countries. I’d like to think that because the temperature is much colder and we’re exposed a lot more we can handle it idk

  • Reply May March 6, 2018 at 8:47 pm

    I have the flu right now and I'm also on my period…

  • Reply Beagle Dog March 6, 2018 at 9:36 pm

    Im nine years old and in January I had the flu and survived!!!! In the worst flu season

  • Reply Beagle Dog March 6, 2018 at 9:37 pm

    When I had flu I somehow felt no pain at all

  • Reply Anista Clark March 8, 2018 at 3:42 am

    At certain offices, they save all the flu shots for the pregnant women bc they absolutely can’t get sick. Also anyone under the the age of 18 is not allowed in the maternity ward of some hospitals bc of this flu.

  • Reply david smith March 8, 2018 at 7:10 pm

    Every morning now i have a small glass of honey and lemon, a garlic and horse radish tablet,and a nasal decongestant/ spray. Without these i would be sick.

  • Reply Watermelon March 10, 2018 at 3:21 am

    My mother does not believe in flu shots. I dont think she is right, but I not dead so thats good. Other shots are okay thought, just not the flu, for some reason.

  • Reply Rex II ForSure March 10, 2018 at 5:38 am

    I had the flu so bad that everything I came in contact cane in contact with had little or no odor even my trash and feces, which usually have very strong odors

  • Reply EllaBean March 10, 2018 at 6:23 pm

    I don’t get Flu vaccines (cause they make me get the flu) and I didn’t get the flu this year. So, Idk. Vaccines are important, but the flu vaccine doesn’t work.

  • Reply Phi Le March 10, 2018 at 6:38 pm

    I have a flu

  • Reply Cat Loving Trio March 11, 2018 at 7:11 pm

    Scientists don't except to guess right, but they try to get as close as possible for maximum benefits. In a recent year, they guessed completed correct!!! Must have been one of the best flu seasons in the world.

  • Reply iCrypx March 13, 2018 at 12:32 pm

    Please Please dont hit philippines i live in philippines and im a kid

  • Reply Lieutenant BoltZ March 14, 2018 at 1:33 am

    I did not get my flu shot because i forgot or my mom forgot and didn't want to take me to get a flu shot. Next time im going to put a giant sign saying "I NEED MY FLU SHOT!!!" So that i dont get that sick. Also is coughing a little and having a stuffy nose the flu? Because i have been coughing a little and had a stuffy nose. I had a major sore throat but that has healed a little.

  • Reply Digant Vora March 15, 2018 at 9:24 am

    Hello Scishow, I would like to know why Ayurveda is not so famous or is it not effective enough ??

  • Reply Melesha Johnson Brown March 16, 2018 at 1:49 am

    im in jamaica and im so sick right now

  • Reply Lil Jimmy March 26, 2018 at 7:37 am

    I was able enough to recover from this quickly just in 3 weeks. It's more of a very rare cough now.

  • Reply dolebiscuit March 26, 2018 at 10:52 am

    Why not vaccinate against nearly every possible variant of flu?

  • Reply Boo Rhyne March 29, 2018 at 12:40 pm

    Me: "Thank god the flu epidemic has died down!"
    Learns that there's a new strain worse then the usual flu

  • Reply Vitamin April 9, 2018 at 10:52 am

    Great, i have a sore throat, watery eyes, i have a fever of 350°F – 100°F, a mild headache, and a little tired…
    Why me?! ?

  • Reply Joshua K. Parker May 14, 2018 at 6:33 am

    QUESTION PLEASE: Why are teeth so delicate. They can kill when decaying and infected. Yet are pretty important to help survive. But in comparison to the rest of the body, more attention seeking when cleaning. Cheers scishow my 4 year old nephew and I catch up every Monday. Thank you.

  • Reply GoonerKIRK May 22, 2018 at 6:54 am

    i got the flu and it's spring!!

  • Reply Jelly Jelly_the100 May 26, 2018 at 3:24 am

    I heard that in 2013 the flu was so strong that it killed the cells even the flu drop and 1,000,000,000 people was dying in that and all of the flu people went to the hospital and 1,025 people died

  • Reply Becky Segundo June 16, 2018 at 6:03 pm

    Flu shots protected me better when I was younger. Only caught the flu once every 5 years. As I get older its every year or 2. This year it morphed into bacterial pneumonia.

  • Reply hombre guapo June 16, 2018 at 10:47 pm ,

  • Reply Gypsy Lady September 29, 2018 at 11:10 am


  • Reply Supahfly uk October 5, 2018 at 3:34 am

    We are due a good strong pandemic, it will thin out the herd.

  • Reply Ari Edge December 1, 2018 at 4:29 pm

    what??? flu

  • Reply Pamela Poore December 11, 2018 at 8:26 am

    Had flu ,know have pneumonia, got the flu shot for the last 6yr. Have had right after flu shot last 3 years and got bad rash after last 2years, I really think we are targeted just for experimental mules!!

  • Reply Carla Head January 5, 2019 at 9:22 pm

    I’m taking a Biologic to help keep my Crohn’s disease in remission which is Humira(adalimumab) (I take the pen) once a week,and Crohns causes me to have a week immune system ; Crohns is a chronic incurable digestive disease in which the immune sys5em mistakingly attacks the digestive disease ,causing inflammation. I do take a flu shot every season and I took the pneumonia vaccine this year too. What are my chances of catching the flu? What would be my chances of getting the flu without taking the flu vaccine,and the last time I had the flu was in 2005 I believe and I had the bird flu -which strain is the dominant bird flu strain,and why isn’t the flu vaccine effective some years? I’m just tempted not to even take the flu vaccine if I’m going to get the full blown flu-why bother,you know? I may not even bother taking The flu vaccine any more. Does anyone know what strain is the most prevalent this flu season?

  • Reply Sheryl Daisley January 11, 2019 at 8:02 pm


  • Reply OhhhPlease January 15, 2019 at 4:01 am

    new air and surface tech released

  • Reply Paul Blake January 25, 2019 at 5:19 am

    Every New Flu Virus Starts In Asia, and Then Spreads To The Rest Of The World, "WHY?"
    —The Answer: Because farmers in China, since recorded history, have always raised their Pigs, Geese, Ducks, and Chickens together!

    2. THE PROBLEM… Pigs can pick up both Avian(bird) and Human Viruses and create a new virus! And re-infect back to the humans, and birds! Like infecting the farmer and his family! Which moves the new yearly flu virus to big Chinese cities, and via Airliners to USA and the World.

    3. And this is exactly what happened in the 14th century Plagues of Europe. Those plagues moved from Chinese farms, via ships, armies, and caravans to Europe, killing 1/3 of the population!

    4. Brian Bossak, an environmental health scientist at Georgia Southern University. Hemorrhagic virus — which causes bleeding and fever, like ebola — swept through 14th-century Europe.
    Plagues like the Bubonic, Black Death and etc plagues?pb

    5. If the Center for Disease Control (CDC) and the World Health Organization (WHO). Told China, to forbid their farmers from allowing their Pigs, and Birds from mingling! That would stop many communicable diseases on Earth, in probably less than a year!


    7. And healthy people are only worth happiness and prosperity to their families, their society, and the World!

    Happy Healthy Trails…
    Doc Blake

    References: (note, because of censorship, you may have to use article title as a Search)
    —Asia is the Traditional Cradle of Influenza – Health – Infectious diseases …@t
    Feb 2, 2004 – For much of the past century, Asia has been the cradle of influenza, including … of the new human flu strains the last few decades appeared in China first. … of peasant farmers keeping ducks, chickens and pigs together with the family has long created opportunities for influenza to jump the species barrier.

    —Sars & Other New Diseases: Whale, @t Many rural Chinese farmers raise flocks of geese side-by-side with herds of swine @t

  • Reply sunny day March 28, 2019 at 6:35 pm

    i once had a bird called enza. i opend the door and influenza

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