What is the Seasonal Flu Vaccine?

What is the Seasonal Flu Vaccine?

Personally, I like the fall. I like the cooler weather and watching college football.  I like to see the autumn light hang on orange and gold leaves, the ground dappled with half-shadows. But the fall is not just the “[s]eason of mists and mellow fruitfulness.” It’s also the flu season, and that means it’s time to talk about the flu vaccine.

What is the seasonal flu vaccine?

It’s important to understand that influenza is not one virus; but, part of a family of very similar RNA viruses called orthomyxoviridae. When you receive the seasonal flu vaccine, you are receiving particular strains of influenza, which doctors and other experts from places like the Centers for Disease Control (“CDC”) and World Health Organization (“WHO”) believe are most likely to be prevalent for a given season and may cause an epidemic. This is why the seasonal flu vaccine changes every year. Influenza viruses can mutate regularly.

Every year, the CDC and WHO recommend specific strains of Influenza A and B they believe will be prevalent for inclusion in the seasonal flu vaccine. Using that information, drug companies making vaccines  begin culturing these specific strains. Traditionally, the companies did the culturing in eggs. These days, they can also culture strains in live cells or use a recombinant process.

Seasonal flu vaccinations are either trivalent or quadrivalent. The trivalent vaccine contains two strains of Influenza A virus and one of Influenza B. The quadrivalent includes an additional strain of Influenza B. (Experts believe that Influenza A and B are the only genera of orthomyxoviridaelikely to cause serious epidemics among humans.)

The seasonal flu vaccine doesn’t have to be an injection, either. Those of us who don’t like needles might be able to receive a nasal spray form that differs slightly from a normal shot.  The nasal spray uses live attenuated virus strains.  Because of the formulation of the nasal spray, it is not always as effective as the shot and when available is only recommended for certain types of individuals and age groups.

With the number of vaccine types available it might seem hard to choose which one to get. Ultimately, this is a question you and your doctor should discuss thoroughly. But no matter which seasonal flu vaccine you decide upon, it should be covered under the National Vaccine Injury Compensation Program if you are injured as a result.

Is there another kind of flu vaccine?

Sometimes, very rarely, a flu strain that was not chosen to be included in the seasonal flu vaccine for a given year becomes prevalent and runs the risk of becoming a pandemic.  In that setting the CDC may recommend a monovalent vaccine (that is, a vaccine with only one particular strain of influenza) in addition to the seasonal flu vaccine. For example, in 2009, a surprise outbreak of the Swine Flu led experts to recommend a vaccine for that specific pandemic (H1N1 vaccine).

The National Vaccine Injury Compensation Program does not cover monovalent influenza vaccines developed in response to a pandemic. Instead, the Countermeasures Injury Compensation Program does.

What side effects can I expect from the Seasonal Flu Vaccine?

Most side effects are extremely mild. The spot where you received the injection may feel sore, or get a little red. Depending on the vaccine, you may itch at the injection site. Some people experience flu-like symptoms such as headaches or muscle aches after receiving the vaccine, and a few run low grade fevers. None of these symptoms are particularly dangerous or likely to last very long. Nonetheless, in very rare circumstances, serious injuries can result from the seasonal flu vaccine.

What if my side effects are more severe?

If you experience severe side effects, the CDC recommends you call your doctor and or seek medical attention right away. And because the National Vaccine Injury Compensation Program (“VICP”) covers seasonal flu vaccines, a qualified vaccine attorney may be able to help you receive compensation for your injuries.

The VICP compensation table lists several injuries as “table injuries” for the seasonal flu vaccine. That means that if you bring a case in vaccine court, the government will have the burden of proving the vaccination did not cause the illness. The following are table injuries for seasonal flu vaccine:

  1. Anaphlyaxis (severe allergic reactions; also called anaphylactic shock)
  2. Vasovagal syncope (also called fainting, syncope, a syncopal episode, vasovagal response, etc.)
  3. SIRVA (an acronym for “Shoulder Injury Related to Vaccine Administration”)
  4. Gullain-Barré Syndrome (also called Acute Inflammatory Demyelinating Polyneuropathy)


Some people experience severe allergic reactions up to four hours after they first receive the seasonal flu vaccine. Your throat may begin to swell, blocking air from your lungs. You may vomit or feel dizzy. Your heartbeat may become irregular. The technical term for such reactions is anaphylactic shock.

A variety of vaccine components can cause anaphylaxis. In particular, people with egg allergies may wish to be cautious, because many seasonal flu vaccines are cultured in egg cells. While many people with egg allergies receive the vaccine with no ill effects, others may risk injury, depending on how severe their allergies are. The CDC has a convenient webpage with more information about egg allergies and the seasonal flu vaccine.

The CDC also identifies gelatin and antibiotic allergies as potentially dangerous, depending on severity.

Vasovagal Syncope

Some people faint when receiving vaccines, the flu shot included. On their own, these “syncopal episodes” may not cause long-term injuries. However, in some instances, people fainting fall and injure themselves. If you have a vasovagal response up to an hour after you get the vaccine, you may have a table injury.


Where you receive a shot can matter as much as what kind of shot you get. As this Wired article observes,

“When a vaccine is injected too high on the arm, the needle intended to go into the arm muscle instead goes into the bursa, a fluid-filled sac that protects the tendons of the shoulder. Vaccines are supposed to provoke the immune system, and here, they provoke the immune system to attack the bursa, leading to pain and sometimes a frozen shoulder. With steroids and physical therapy, some patients are able to recover—but not all.”

In rare cases SIRVA can decrease your ability to move your shoulder comfortably.

The vaccine compensation table lists SIRVA, like fainting and anaphylaxis, as a table injury for most vaccines. This shoulder injury needs to surface within two days to count as a table injury. News reports suggest that petitioners increasingly file claims for SIRVA with the vaccine court.

Gullain-Barré Syndrome

Gullain-Barré Syndrome (“GBS”), also called Acute Inflammatory Demyelinating Polyneuropathy (“AIDP”) (although it can also refer to other related variant illnesses), is an autoimmune disease that targets the myelin in your peripheral nervous system.   It generally results in rapidly ascending decrease in or loss of sensation and reflexes which can ultimately affect breathing.  Although most people who suffer GBS make a full recovery, in rare cases it may lead to paralysis or even death. If you ever have had GBS the CDC recommends that you speak to your doctor before getting the seasonal flu vaccine.

Cases of GBS that develop between three and forty-two days after vaccination for seasonal influenza also count as a table injury.

Can I be compensated if I suffer an injury?

The National Vaccine Injury Compensation Program covers seasonal flu vaccines. If you can prove your injuries resulted from your vaccination, you may be eligible for compensation. Your injuries do not have to be “table injuries,” like those listed above. The vaccine court considers non-table injuries, too. The program may compensate you for past and future medical expenses, pain and suffering, lost wages, or “impaired earning capacity.” An experienced team of legal professionals can help you make your claim.

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