Get ready—flu season is closer than you think

Last year’s flu season was bad. Hopefully this year’s will be better (for us, not for the virus). The CDC is changing the recommendations a bit to improve the population’s coverage, and I’m hoping I won’t be quite as busy this winter.

Last year, I provided you with weekly flu activity updates. I’ll probably do that again, but I think we need to kick off the season with an influenza primer. Get ready for some science! (BTW, for a more extensive look at influenza biology, see Effect Measure.)

The Disease

The flu is misunderstood. It is a respiratory illness, not a “stomach bug”. Is is passed through contact with respiratory secretions, such as sneezing and coughing. Infection leads to a sudden onset to fever, muscle pain, and fatigue. Often, there is a dry cough, runny nose, and watery eyes. People with the flu look and feel miserable.

Influenza is a dangerous bug, responsible for around 35,000 deaths yearly in the U.S. This number is arrived at by statistical analysis of excess deaths due to influenza and pneumonia during the winter months. Flu itself sometimes kills people, but influenza is often complicated by bacterial pneumonia. Flu shots prevent the flu, but can also make a flu less dangerous should you catch it anyway. Flu shots are a “very good thing” (but not a sure thing).

The Bug

Influenza is a virus that affects many different animals, including humans. In humans, it occurs as seasonal epidemics, and occasionally global pandemics. Unlike smallpox, polio, and other viruses for which a single vaccine formula is preventative, influenza prevention requires the development of a unique vaccine every season. This is where biology comes in handy.
One way our bodies recognize viral invaders is by the chemicals displayed on their surfaces. In the case of influenza, the two most important surface chemicals are neuraminidase (NA) and hemagglutinin (HA). Small changes occur in the RNA of flu viruses over time, leading to changes in the surface molecules. Even small changes in these surface molecules can change our immune system’s ability to respond to an infection. This process of small changes is called “antigenic drift”, and is responsible for yearly influenza epidemics. (Any molecule recognized by the immune system is called an “antigen”, and the flu surface molecules are important antigens.) The slightly changed virus is more successful than other flu viruses, and becomes dominant during that season (evolution in action!).

Sometimes, flu virus antigens undergo major changes that make them entirely unrecognizable to the human immune system. This is called “antigenic shift” and involves a big change in the flu’s surface molecules. One way this can happen is when a human and animal flu virus co-infect a host and share genetic information. These antigenic shifts are responsible for flu pandemics, as the antigens are new to human populations and spread very easily.

Preparing for antigenic shifts isn’t so easy, but since antigenic drift is happening continuously, it can be tracked and documented. Epidemiologists track the flu across the globe to see what strains are likely to cause trouble during flu season, and use that information to develop the yearly vaccine. The vaccine usually contains three antigens that are predicted to be prevalent in the upcoming season, and even if the coverage is partial, it can reduce the number and severity of cases.

So get ready ‘cuz here it comes.


  1. Given CDC and census information, only 30% of the US population is vaccinated and last year only 1 in 8 was effectively vaccinated. Given the effectiveness of last year’s batch, it might be an uphill battle for this year’s vaccine.

  2. I’m the State Flu Surveillance Epidemiologist in my state, and it is always difficult to get health care providers to give us data like the number (proportion) of patients visiting with influenza-like illness. So all the numbers provided by CDC and state health departments must be acknowledged to be under-estimates of the true activity of the disease. And I agree that it’s going to be an uphill battle to get people to take the shot. Sadly, most of these people are the same ones that would not think twice to sue someone if they ever got some bad side-effects from the flu. Right now, I’m prepping our system to start collecting, analyzing, and reporting the data on September 29… And I’m getting way more “no, thanks” from providers than “sure, I think it’s a worthwhile endeavor which will not only benefit my practice and my patients, but it will also benefit the community at large.”

  3. Chuck said (predictably):

    Given the effectiveness of last year’s batch, it might be an uphill battle for this year’s vaccine.

    What does one have to do with the other? It is a non sequitor.

  4. PAL,

    “What does one have to do with the other? ”

    If one has nothing to do with the other, than why isn’t more of the poulation getting vaccinated and the situation described by Ren happening at all with educated health care providers?

  5. Natalie

    If one has nothing to do with the other, than why isn’t more of the poulation getting vaccinated

    You’re creating a false dilemma here. Surely there are other reasons to not get a flu vaccine? I haven’t gotten in previous years because I’m young and relatively healthy, and when they were concerned about shortages it seemed unfair to take a vaccine that someone else might need more. Some people may not get them because they don’t think being vaccinated is worth the money.

  6. Most of the people that dies during the 1918 pandemic were young and relatively healthy… It didn’t turn out too well for them. And, when you compare apples to apples, getting the shot actually saves money not only to you but to the rest of us. Herd immunity is a wonderful, wonderful thing.

  7. Chuck, the efficacy of last years batch has no bearing on the design and production of this year’s batch. The vaccine is designed anew each year. They are independent events.

  8. Natalie,

    Why wouldn’t the arguments you presented be applicable to all vaccines then?

  9. PAL,
    “Chuck, the efficacy of last years batch has no bearing on the design and production of this year’s batch. The vaccine is designed anew each year. They are independent events.”

    I know that. You know that. Does the general public know that? Who is to say that this year will be more effective than last year?


    30% is not herd immunity and 30% is with 100% effectiveness.

  10. The only excuse that I have heard for ppl not getting vaccine is that it might cause the flu. No arguing would change their mind. Too many stories of ppl getting the shot then getting sick.


  11. tomS,

    How about the vaccine isn’t always effective and there are more reliable ways to reduce your risks of getting the flu.

  12. Whoo, cool picture! I know I am adding nothing here.

  13. I hope they do a better job this time. Last year my flu shot barely did anything, and I caught it pretty bad. That probably wasn’t helped by the fact that my heater conked out in the middle of the night during winter and it took two weeks for my apartment complex to remedy the situation.

  14. Chrissl

    My guess is that a big part of people not getting flu shots is a combination of not paying attention and the sheer inconvenience. First, the attention thing: it has only just begun to penetrate the public consciousness as a routine recommendation. It’s not that many years since it was *only* recommended for the elderly and frail. Second, it’s not a one-step process: most of us have to remember to phone the doctor’s office, re-arrange the work/transport/child schedule and keep the appointment. And where and when you are supposed to go changes every year. Minor obstacles, I know, but they add up. More drop-in arrangements would be helpful — that at least reduces the process to one step, “Stop at flu shot clinic.”

  15. speedwell

    I’m going to Germany for a business trip the last two weeks of September, and off to Dubai the last two weeks of October. Do you recommend I get a flu shot before I go? Is there a certain kind I should get? I know about the other immunizations but I’m specifically asking about the flu because the Health Department’s information was not very clear. Thank you.

  16. Huh, flu shot’s always been convenient for me. At my last Real World job in a not very big startup, they brought someone in to give shots. Campus health center gives shots to walk-ins, okay I’m lucky there, but the supermarkets also have a few days in which there’s someone giving shots.

  17. Do some people actually seriously think that flu is a *stomach* bug? That’s right up there with thinking the common cold is a disease of the eye…

  18. “stomach flu” is common usage in the U.S.

  19. For years, as a US military employee, I got free flu shots at work. Several local grocery stores offer flu shots; you can make an appointment on line/in person or just show up during designated hours. It was $28 last year.

  20. Julie Stahlhut

    A lot of employers, especially hospitals and universities, offer free flu shots. Mine (the University of Rochester) does. Others partially subsidize one.

    I started getting yearly flu shots when I used to do computer support in a hospital, and had to set up some software for physicians in the ambulatory-care center. Since most of them had their computers in their offices, I had to sit in the waiting room with everyone else until the doctors were finished seeing their patients. After being coughed at on many occasions, I started rolling up my sleeve every year.

  21. You would think with all these touching anecdotal stories that the vaccination rate would be higher, but it is not.

  22. You would think that with all the times Chuckles has been spanked, mocked, and generally laughed at, that he would learn, but he doesn’t.

  23. Obviously LanceR knows more than the CDC when it comes to vaccination rates. Please LanceR, enlighten the CDC and the rest of us with your vast knowledge of actual data and the source.

  24. Chuck, i haven’t the faintest idea what point you’re trying to make. Efficacy/utility of vaccines isn’t an issue of democracy. If vaccination rates aren’t where we would like them, it’s up to us to provide better public health information, and to get idiots like you to shut the fuck up.

  25. I’m just relaying the pertinent public health information pertaining to the topic at hand from the government agency dedicated to this topic. If you don’t like the information they are required to report then you can tell them to, as you so eloquently put it, “shut the fuck up”.

  26. You’re making no sense at all…really…

  27. In democratic terms, a super majority of the population (70%) do not see the need to get the influenza vaccine. They must either see it as unnecessary or ineffective. The 70% isn’t a onetime number, it has been trending like that for years. If public health information hasn’t been able to change this trend, what will?

  28. In simple terms, Chuck, it has only been a few years that doctors have been recommending that EVERYONE get the flu vaccine. In past years, they have only recommended that the elderly and at risk people get the vaccine.

    As has been explained to you a thousand times, the efficacy of the vaccine has nothing to do with the vaccination rates. But you are too blinded by your ideological desire to paint all vaccines as bad to actually see or admit reality.

    You are a narrow-minded moron. I am done with you.

    So, have you stopped beating your wife yet?

  29. In simple terms LanceR,
    The influenza has been available to everyone for years as the anecdotal stories above clearly represent and yet a vast majority of the population does not see it as worthwhile to get it.

    Have you stopped sexually abusing children yet?

  30. One more time, to really dig past all the ideological bunk in Chuck’s head.

    Your argument is irrelevant. Like most of your arguments. The gabbling of chickens is more relevant than your arguments.

    Stop beating your wife yet? I stopped with children when I stopped being one… how ’bout you? Last week?

  31. In case you missed it, my point is simple: whether you’ve stopped beating your wife yet is irrelevant to the discussion. It is exactly as relevant as how many people have taken the vaccine is to how effective the vaccine is.

    Also, it’s very difficult to prove a negative. Isn’t that what you twits are always demanding? “Prove it doesn’t work” and all that garbage?

    This isn’t just baseless accusations.

  32. Chuck apparently thinks science is done by voting…the analogous argument is if not enough people with heart disease aren’t on aspirin, then aspirin must not be good (it is!)

  33. Of course! The ever popular Argumentum Ad Populum! How could I have been so blind! Of course he’s right! Oh… wait… no.

  34. theFluLie

    Yes, don’t forgot your flu shot! What did the CDC report in 2005? 1,806 deaths from the flu with the majority in people over 75. Yet, they tell us 20,000 people die each year?

  35. LanceR,
    “In case you missed it, my point is simple: whether you’ve stopped beating your wife yet is irrelevant to the discussion.”

    If it is irrelevant, then why did you bring it up? Can’t you stay on topic or are you ADHD?

    “Chuck apparently thinks science is done by voting.”
    Peer reviewed studies are a vote.

    You quote influenza vaccine effectiveness, but the influenza vaccine is designed by a vote of which strains to use.
    A 30% population coverage is a vote of “no confidence” in the current process. Fix it!

  36. More deliberate obtuseness from Chuckles! Is he pining for a Trollympics rematch? Is he just lonely? Or is he just a liar with an agenda?

    Stay tuned for more obnoxious droning on the BFL channel!

  37. All of us want to become healthy, especially now that we are experiencing a sudden economic crisis, of course, we cannot afford that one of our family members to get sick. That’s why we are taking vitamins and eat balanced diet. But now that the autumn leaves are falling and the air outside is cold. These are some of the signs that flu season is upon us once again. You should already know that washing your hands is the easiest, most inexpensive way to prevent any illnesses from spreading, including the flu virus. It is important that you�re aware of the severity of this virus. About 226,000 people are hospitalized every year, and almost 36,000 people die each year on behalf of the flu. Unfortunately, this virus not only takes a toll on your body, but on your budget as well. Health experts suggest getting an annual flu shot, which typically cost $25-$30. Okay, that sounds like a reasonable price. However, when you have a family of five, those $30 shots add up quickly! In addition to that, other treatments along with hospital visits can be expensive too. If you need help this pay period, a payday cash loan can help cover those medical bills, not to mention save you future financial hardships.
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  38. All of us need to be ready for the flu season. Remembering to wash your hands regularly can go a long way to preventing the flu.

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