Getting A Flu Shot: No Guarantee It Will Work

Getting A Flu Shot: No Guarantee It Will Work
nerdy guy with tissues up his nose
When beliefs about vaccine effectiveness are not grounded in truth, they can put you, your family and people you know at risk.

Like a lot of people, in January when I suddenly developed a high fever (101 F), body aches, fatigue, nasal congestion and cough, I thought for sure it was influenza, which I had not experienced for decades. Turns out, according to a recently released CDC report, in the 2016-2017 flu season the odds are only about one in 10 that flu like illness symptoms are, in fact, caused by type A or B influenza.

On Feb. 17, 2017, the Centers for Disease Control published an update on influenza activity in the U.S. for four months between Oct. 2, 2016 and Feb. 4, 2017.1 The new news is the CDC found that over the past four months:

  • Influenza A (H3N2) viruses accounted for the vast majority of all public health lab confirmed influenza cases;
  • Out of nearly 393,000 respiratory illness lab specimens tested in the U.S., only about 38,000 cases—or 10 percent—were positive for type A or B influenza;
  • Persons over age 65 accounted for more than 60 percent of lab confirmed influenza-associated hospitalizations;
  • About 6,800 hospitalized cases of lab confirmed influenza have been reported so far and it is estimated that about 95 percent had at least one high risk medical condition, such as heart disease; metabolic disorder or obesity, with more than half of the children hospitalized also suffering with asthma, chronic lung disease or a neurological disorder;
  • About 5 to 8 percent of all U.S. deaths reported over the past four months have been attributed to pneumonia or influenza, with 20 reported pediatric deaths associated with type A or B influenza;
  • The influenza strains included in this year’s flu vaccine are closely matched to the most prevalent influenza strains reported to be circulating in the U.S. Out of 484 different influenza viruses the CDC tested, 96 to 100 percent of influenza A viruses and 91 to 100 percent of influenza B viruses were antigenically similar to components of the 2016/2017 influenza vaccine.

CDC: This Year’s Flu Shot Only 43 Percent Effective Against Most Prevalent Strain

The old news is that, even when this year’s seasonal flu shot contains the same influenza strains that are circulating—like in most years2 —it is less than 50 percent effective across all age groups in preventing a trip to the doctor’s office for lab confirmed influenza. The vaccine is only 43 percent effective in preventing influenza A (H3N2), the most prevalent strain this year.

How many people following doctors’ orders and rolling up their sleeves to get an annual flu shot this year understand it has a 57 percent failure rate for the most common influenza strain circulating? That is like telling someone to buy a car with seat belts that fail 57 percent of the time!

But, beyond that, how many people understand that only 10 percent of all flu-like illness out there this year is actually influenza?

There are no guarantees in life. That goes for vaccination, too.

Vaccines Often Fail to Prevent Infection and Transmission

While many people believe that getting vaccinated guarantees you won’t get sick or make anyone else sick, vaccines do not always work as well as we have been taught to believe they do.3 

Take influenza vaccines, for example. Influenza is a viral infection that causes type A or B influenza, which can have serious pneumonia complications for some people, like the elderly.4 

Doctors routinely give annual flu shots to children and adults, including pregnant women.5 6 7 And in many states, health care and day care workers are required to get an annual flu shot or they are fired from their jobs.8 9 10 

But public health officials admit that influenza vaccines fail to prevent influenza more than half the time.11 And in some years, flu shots do not prevent influenza at all because they don’t contain the influenza strains that are making people sick.12 

Plus, you can get a flu shot and still get infected with influenza but only have minor symptoms or no symptoms at all.13 Even if you have been vaccinated, you can be a silent carrier of influenza and infect other people without even knowing it.

This is something to keep in mind when you are in a doctor’s office or hospital, where all employees have been vaccinated and assume they are protected, but where influenza could still be circulating among the staff.

Most Flu Like Illness Not Influenza

But perhaps the biggest misconception of all is that during the flu season, every time you get a fever, headache, sore throat, cough, and a tired, achy feeling all over, you probably have influenza that could have been prevented with a flu shot.

The truth is that, when doctors get suspected cases of influenza tested in labs, more than 70 percent of the time it is not type A or B influenza but another virus or bacteria causing a respiratory flu-like illness that is mistaken for influenza.14 15 

When beliefs about vaccine effectiveness are not grounded in truth, they can put you, your family and people you know at risk.

Whether you have been vaccinated or not, if you have even mild symptoms of being sick, stay away from close contact with infants, pregnant women and people who are immune compromised until you are well.


1 CDC. Update: Influenza Activity – United States, October 2, 2016 – February 4, 2017. MMWR Feb. 17, 2017; 66(6): 159-166.
2 CDC. Seasonal Influenza Vaccine Effectiveness 2005-2015. Dec. 18, 2015.
3 Fisher BL. Pertussis Microbe Outsmarts the Vaccines As Experts Argue About WhyNVIC Newsletter Mar. 27, 2016.
4 Agency for Healthcare Research and Quality. Influenza Most Deadly for the Very Elderly. AHRQ Press Release Nov. 7, 2006.
5 CDC. Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP) – United States, 2016-2017 Influenza SeasonMMWR Aug. 26, 2016; 65(5): 1-54.
6 CDC. Guidelines for Vaccinating Pregnant Women. August 2016.
7 Fisher BL. Vaccination During Pregnancy: Is It Safe? NVIC Newsletter Nov. 9, 2013.
8 Fisher BL. Women, Vaccines and Bodily IntegrityNVIC Newsletter Jan. 24, 2013.
9 DeSerres G, Skowronski DM, War BJ et al. Influenza Vaccination of Healthcare Workers: Critical Analysis of the Evidence for Patient Benefit Underpinning Policies of Enforcement. PLOS One Jan. 27, 2017.
10 Lin RG, Xia R. Vaccines required for daycare workers under new California law. Los Angeles Times Oct. 13, 2015.
11 Fisher BL. CDC Admits Flu Shots Are Effective Half the TimeNVIC Newsletter Apr. 26, 2017.
12 Fisher BL. Flu Vaccine: Missing the MarkThe Vaccine Reaction Spring 2004.
13 The Lancet. Three-quarters of people with seasonal and pandemic flu have no symptoms. Eurekaalert Mar. 16, 2014.
14 CDC. Update: Influenza Activity – United States, October 4, 2015 – February 6, 2016. MMWR Feb. 19, 2016; 65(6): 146-153.
15 CDC. Influenza Activity – United States, 2014-2015 Season and Composition of 2015-2016 Influenza Vaccine. MMWR June 5, 2015; 64(21): 583-590.

2 Responses to "Getting A Flu Shot: No Guarantee It Will Work"

  1. Joanne Sgrignoli   March 22, 2017 at 12:09 pm

    I have serious reservations about vaccinations, and great trust issues with government entities that have withheld truth.

    Having said that, I understand that the flu mutates and that there are many strains, but I am high risk (asthma, lung disease), so I’very been getting flu vaccines for longer than I remember.

    Before the flu vaccine, or perhaps before I got the flu vaccine, I contracted the flu every January. I was violently I’ll, with a fever, chills, vomiting, diarrhea, and sometimes sore throat and couching. Since getting the flu vaccine I haven’t gotten the flu, even from selfish people who came to work with it to maintain sick leave records, or whatever other absurd excuses there were. I avoided them like the plague.

    Unless there is a compelling reason not to not get the flu vaccine, or if its effectiveness decreases substantially, I will continue to get it. I prefer it without mercury.


  2. RICHARD L. BRANDON, MD   March 26, 2017 at 9:22 am

    CDC claims 43% effectiveness in preventing flu. They have no idea how many cases, if any are prevented. They simply measure antibody reaction and not prevention.


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