Ultimate Guide To Flu Shots

Ultimate Guide To Flu Shots

Do you get the flu shot each year?

If not, maybe you’re worried about the potential side effects – or simply feel that it is ineffective. You’re not alone.

There’s a lot of controversy and aroused passions when it comes to the influenza vaccine.

In this ultimate guide to flu shots, we lay out the facts so that you can make an informed decision.

Flu Shot History

Actors In Theaters Getting The Flu Shot

You may have heard of the Spanish Flu Epidemic of 1918-19.

Back then there was no such thing as an influenza vaccine.

As a result, the epidemic caused a swathe of death across the planet that was responsible for twice as many deaths as the entire four-year killing spree that was World War One.

In 1918, scientists were not even aware of just what caused the flu. Still, desperate researchers scrambled to do something to end the death toll. 

In 1919, Edward Rosenow from the Mayo Clinic isolated several bacteria from the sputum and lungs of flu patients.

From this, he was able to produce a vaccine that provided protection from five strains of influenza. Rosenow administered the vaccine to a hundred thousand people. 

Around the same time, Dr. Timothy Leary (grandfather of the hippie leader of the 1960s) produced his own influenza vaccine.

Leary’s vaccine was produced from a combination of strains from the Chelsea Naval Hospital, a nurse’s nose at Carney hospital and the infected wards of a military hospital.

This vaccine was used to innoculate 18,000 people in San Francisco. 

These efforts to produce a flu vaccine reduced what was known as ‘flu phobia across the United States in the early 1920s.

However, it was not early to know if either of the vaccines actually worked. 

Research into the flu vaccine picked up pace in the early 1930s. In 1933 the flu virus was isolated, allowing researchers to have a specific target to combat.

In the mid-1930s the USSR began a massive inoculation program using a weakened version of the virus.

Illustration Of Vaccine Problem

However, there was no definite testing done to assess the effectiveness of the vaccine.

There remained the danger that the live vaccine could cross with other strains to morph into a more powerful version of the virus.

Researchers in the United States focused their efforts on producing an inactive version of the flu vaccine.

The virus was grown inside chicken embryos and then dunked in a bath of formalin to render it inactive.

This approach required a higher amount of the inactive vaccine, but, at least there was no longer any danger of the virus replicating!

The first US versions of the vaccine were designed to combat just one strain – Influenza A. At that stage, researchers were not aware that there were any other strains.

However, in 1940, they identified a new strain, which they labeled as Influenza B. From that point on, the challenge was to develop new strains of the flu vaccine to combat emerging strains. 

By the early 1950s, American researchers had developed a vaccine to protect against both strains of influenza vaccine.

Then, in the late 70s, a third vaccine strain was discovered. By 2016, the majority of flu vaccines were able to protect against four strains of the virus.

As a result, they were labeled as quadrivalent. The hunt is now underway to come out with a super vaccine that will cover every strain and provide protection for a number of years.

Finding the Ideal Vaccine

Placing A Slide Under A Microscope

An effective vaccine will match the specific level of protection to the particular strain of the influenza virus that is prevalent in any given year.

The big problem with achieving this result is getting the vaccine out in time once the current strain is identified.

The length of time to produce a vaccine and have it authorized for general administration is about six months.

As a result, the Wolrd Health Organization (WHO) undertakes a type of detective work each year to identify the current strain of flu as soon as possible. 

The WHO maintains 110 flu centers in eighty countries. At these locations, swabs taken from people with influenza-like symptoms are analyzed.

From time to time, these researchers will identify a new strain of the flu.

Twice a year, the WHO convenes a meeting to sift through all of the gathered information and recommend a vaccine to treat the current strain for the upcoming flu season.

In the United States, the CDC and the FDA will have the ultimate say as to what goes into the vaccine that is used throughout that country.

Viruses can mutate very fast. It is possible that, by the time the vaccine is administered, the virus will have mutated to the extent that the vaccine is actually a mismatch.

As a result, most years the vaccine is, at best, 50-60 percent effective. Sometimes it is much worse than that.

During the 2004-5 flu season, the influenza vaccine was only 10 percent effective. Then in 2014-15 when the H3 strain was identified, the success rate was just 19 percent. 

Even the most effective vaccine will have different success rates in different population demographics.

Arm Flu Shot

In general, children will respond better to a vaccine than adults. Perhaps surprisingly, so do the elderly.

That is because, even though they have weakened immune systems, they also have a life-time buildup of natural immunity.

Still, it is highly recommended that the elderly get the flu vaccine. Studies have shown that the flu vaccine can reduce the winter mortality rate among seniors by a whopping 50 percent.

There is also strong evidence that vaccinating one segment of the population, such as school children, benefits other segments, such as the elderly. 

In the United States, the Center for Disease Control (CDC) recommends that every person over the age of six months gets the flu vaccine every year.

They undertake a huge publicity campaign every season to encourage people to do just that.

Recommendations regarding the use of vaccines in the United States are made by the Advisory Committee on Immunization Practices (ACIP).

This group meets three times each year to review new evidence and provide advice to the CDC. 

Other countries are less stringent than the US regarding their flu shot recommendations.

In many countries, healthy adults are not targeted for the flu, with the focus going on young children and the elderly.

With the mortality rate from influenza being so low, it is very difficult to say whether a full vaccination campaign, such as that carried out in the United States, is a better preventative than a campaign that targets the young and the elderly. 

How Effective is Influenza Vaccine for Healthy People?

Flu Shot

In the United States, the Cochrane Collaborative has been seeking to find the answer to this question.

In 2014 the Cochrane Collaborative reviewed every study that evaluated the effects of the influenza vaccine in healthy American adults.

This involved ninety studies with a total population of 8 million people. The results produced by the Cochrane Collaborative was not very encouraging.

Around 2.4 percent of the unvaccinated population came down with the flu, compared to 1.1 percent of those who were vaccinated.

In other words, it would require vaccinating 71 people to prevent a single case of influenza. 

The Cochrane Collaborative also found that the flu vaccine did not reduce the number of workdays lost. Neither did it reduce the number of hospitalizations. 

Is the Flu a Killer or an Irritant?

Illustration Of Flu Virus

The CDC in America promotes the Flu virus as a potential killer, as we can see from this excerpt from their website . . .

It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people,  

such as older people, young children, and people with certain health conditions, are at high risk of serious flu complications.  

The best way to prevent the flu is by getting vaccinated each  


However, the British, who do not encourage universal vaccination, do not mention its potential to be death-dealing. Here is an excerpt from the British National Health Service website . . .

It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people,  such as older people, young children, and people with certain health conditions, are at high risk of serious flu complications.  The best way to prevent the flu is by getting vaccinated each year.

So, what is the truth?

Influenza is not a deadly disease like cancer or heart disease. But, in the United States, it is treated as if it is. As a result, the message from the CDC is to vaccinate every person over the age of six months. 

The CDC reports that between 2010 and 2016 the annual death rate from influenza was between 3,000 and 56,000.

The highest season was 2012-13, with the lowest being 2011-2012. If we take an average of 25,000 deaths per year, that works out at a mortality percentage of .000007.

On that basis, we can not conclude that influenza is a fatal virus. 

How far away is a universal flu vaccine?

Holding Vaccine

There is currently a rush to find a universal flu vaccine.

The ultimate would be to come out with a vaccine that covers every possible strain and that only needs to be given once.

There are many companies that assure us that they are on the brink of coming out with just such a vaccine, but to date, nothing concrete has emerged. 

Flu Shot FAQ

What Exactly Are The Flu Shots?

The flu shot is an annual vaccine that is administered every year to protect people from the influenza virus.

In the United States, the flu shot is recommended to be given to every person in the country who is aged six months or over. 

Because the flu vaccine mutates every year to generate new strains, a renewed version of the flu vaccine is produced every year.

In the United States, flu season is between October and May each year. To afford protection over the entire flu season, the CDC advises getting the flu shot as early in the season as you can. 

Type Of Flu Shots

The types of flu shots are as follows:

Trivalent Flu Vaccine

Trivalent Flu Shot

This vaccine affords protection against three strains of the influenza vaccine:

  • Influenza A (H1N1)
  • Influenza A (H3N2)
  • Influenza B virus

There are three versions of the Trivalent Vaccine:

Regular Trivalent Vaccine

The regular egg grown flu vaccine is administered in the upper arm and given to people between the ages of six months and 64 years.

High-dose Trivalent Vaccine

The high-trivalent vaccine, called Fluzone, is designed for administration to people aged 65 or over.

It is specially formulated to deal with the increase in flu-related complications that come with old age. In fact, 85 percent of flu-related fatalities occur in people aged 65+.

This high dose version contains four times as much flu virus antigen as the regular trivalent vaccine.

The antigen is the portion of the vaccine that stimulates an immune system response to the virus.

Trivalent Vaccine with Adjuvant

The Trivalent vaccine with an added adjuvant is called Fluad. This version is also designed for people in the 65+ age group.

The adjuvant provides a stronger response by increasing the body’s innate immunity to the virus. 

Quadrivalent Flu Vaccines

Vaccine Quadrivalent

As the name suggests, quadrivalent flu vaccines afford protection against four different strains of the flu virus – two Influenza A and two Influenza B. The types of quadrivalent vaccines are:

Regular Standard Dose Quadrivalent Vaccine

This is the standard version of the flu shot that is to be given to all people over the age of six months. 

Intradermal Quadrivalent Vaccine

The intradermal quadrivalent vaccine is injected into the skin rather than directly int the muscle tissue. It is authorized for use in people aged between 18 and 64. 

Recombinant Quadrivalent Vaccine

This vaccine is not grown from eggs. It is specifically designed to be given to people who have an egg allergy. It is approved to be given to all people aged 18 and over. 

Live Attenuated Intranasal Spray

Made with eggs, this vaccine is designed as a nasal spray. Included in the spray is a course of attenuated flu vaccine. 

Who Can Benefit From The Flu Shots?

Girl Taking Flu Shot

All people can benefit from the flu shot. Here is how:

  • The flu shot will make it less likely that you will succumb to the aches and pains that are part and parcel of the flu season.
  • The flu shot will reduce the risk of flu-associated death in children with high-risk underlying medical conditions by 51%. 
  • The flu shot will reduce the risk of flu-associated death in healthy children by 65%.
  • The flu shot will reduce the risk of babies being hospitalized if the mother gets the flu shot.
  • If you have asthma, the flu shot will reduce asthma attacks leading to hospital visits. 

What Are The Side Effects Of The Flu Shot?

There are a number of flu vaccine side effects. They are more often experienced by children, especially those who are getting the flu shot for the first time.

Most side effects are mild and are gone after a couple of days. The most common flu shot side effects are:

  • Pain and swelling at the site of the injection
  • Low-grade fever
  • Muscle aches
  • Fatigue
  • Headache
  • Nausea

On rare occasions, a person may experience an allergic reaction to the flu vaccine.

One of these may be anaphylaxis, which is typified by facial swelling, breathing difficulty, vomiting, hives, dizziness, rapid pulse, or fainting.

This is a life-threatening condition. If it occurs, call 911 immediately. 

It can be difficult for a parent to tell if a child’s feeling of being unwell is a result of the flu vaccine or unrelated.

Some parents have blamed the child’s sickness on the vaccine and decided not to have their child vaccinated again when there was actually no relation.

Here are some questions parents should consider to determine if the child’s unwellness is related to the vaccine:

  • Has the child had the vaccine before without these side effects?
  • Did the symptoms appear within 12 hours of the flu shot? If not, there is probably no relation.
  • What other symptoms are there?
  • Has the child been sick for more than two days? If so, it is probably not related to the flu shot. 
  • Are any other children who had the vaccine similarly affected?

Are There Any Side Effects To The Nasal Version Of The Flu Vaccine?

Nasal Vaccine

Yes, there are some effects associated with the nasal version of the flu vaccine.

These include a runny nose, nasal congestion, sore throat, a cough, low-grade fever, headache, muscle pain, and a general feeling of being out of sorts.


The Flu Shot is the most widely administered vaccine in the United States. 

Each year it helps many millions to ward off the uncomfortable and potentially debilitating effects of the influenza virus.

In this article, we’ve revealed the facts surrounding the sometimes controversial issue of whether or not the flu shot is a smart choice for you and your family.

Now that you’re armed with that knowledge, what will your decision be?

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