The Importance of Influenza Vaccination

Introduction

Vaccination to prevent influenza began in the 1930s. Influenza vaccines or flu jabs (flu shots) are the vaccines that protect against four influenza viruses most common during the changing seasons. Most vaccinations are given intramuscularly, intradermally, or through spray into the nose. They are generally safe and are recommended twice a year.

What Is Influenza?

Influenza is an acute viral infection affecting the upper and lower respiratory tract (nose, throat, and lungs). This is a contagious disease that can be transmitted through contact with respiratory secretions (cough and sneeze), saliva (kissing and sharing drinks), handshake or hug, and by touching contaminated surfaces. In young children, older adults, pregnant women, and people with certain medical conditions, chronic illnesses, or immune-compromised, it can cause severe complications. Annual vaccination is the best alternative to avert the flu. Although the vaccine is not a hundred percent effective, the best direction for prevention is vaccination itself.

What Are the Four Types of Influenza Viruses?

Influenza viruses are classified as:

• Type A - This virus causes excellent influenza epidemics and outbreaks.

• Type B - This is less severe and causes more minor attacks.

• Type C - This variant of influenza causes mild respiratory illness.

• Type D - This variant of influenza infects pigs and cattle.

These variants generally produce similar symptoms but are not related antigenically.

What Are the Symptoms of Influenza?

Influenza can lead to mild to severe illness, and sometimes that may prove fatal.

Symptoms may vary from person to person. However, some of them are as follows:

• Cough.

• Sore throat or itchy throat.

• Fever or chills.

• Rhinitis.

• Body ache.

• Headache and muscle ache.

• Tiredness.

• Vomiting and diarrhea.

How Does the Flu Spread?

The mode of transmission is by:

• Respiratory droplets (cough or sneeze).

• Touching contaminated surfaces.

• Saliva (sharing drinks and kisses).

• Handshaking or hugging infected individuals.

How Many People Get Ill Every Year With Flu?

• It is estimated that around one billion people yearly are infected with the flu.

• Most are children, immuno-compromised individuals, and people older than sixty-five years.

• One might infect others before they are infected and in the infectious phase.

• The contagiousness is maximum during the first three to four days of infection.

• The period of contagiousness lasts from one day before the onset of symptoms up to five to seven days after becoming sick.

How to Prevent the Flu?

Yearly vaccinations are the best way to prevent flu infection. New vaccine versions are developed twice a year because the influenza virus rapidly changes. Since the virus mutates every year, to keep the vaccines effective and provide the highest protection, they are developed every year.

The World Health Organization (WHO) suggests that all individuals above six months of age should get yearly vaccinations. The vaccines are safe; only a few people get muscle pain and feel tired post vaccinations. These symptoms are temporary and disappear in a day or two.

How Many Types of Flu Vaccines Are Available?

There are many different types of flu vaccines available. However, it is recommended to take only licensed and age-appropriate vaccines.

Following influenza vaccines are available:

1. Inactivated influenza vaccine, egg-based (IIV).

2. Inactivated influenza vaccine, not egg-based (ccIIV).

3. Recombinant influenza vaccine, not egg-based (RIV).

4. Live attenuated influenza vaccine, not egg-based (LAIV).

Let us discuss the following:

• Standard Dose Quadrivalent Shots - These are developed using viruses grown in eggs. These include Fluarix Quadrivalent, Afluria Quadrivalent, Fluzone Quadrivalent, etc. Different influenza shots are advised for other age groups. These shots are given in the arm with the needle. Following vaccines are recommended for people older than six months of age.

• Cell-Based Quadrivalent Influenza Shot - These shots are recommended for people older than six months. It contains a virus grown in cell culture and is egg-free.

• Recombinant Influenza Shot - This is also an egg-free vaccine and is approved for people older than 18 years of age.

• Flu Shot Using an Adjuvant - It is recommended for people 65 years of age or above.

• High-Dose Influenza Vaccine - It is licensed for people 65. It contains higher doses of antigens that provoke a more robust immune response.

• Live Attenuated Vaccine - This vaccine is licensed for people between two to forty-nine years of age. It is given intranasally. It is not suggested for pregnant women, immunocompromised individuals, or those dealing with some chronic illnesses.

Most influenza vaccines are prepared using egg proteins. However, those with egg allergies can also opt for them, as no severe allergies have been seen. Vaccines produced using other technologies, such as cell culture, are also available. Depending on the type of vaccine, they can be injected intramuscularly or intradermally and through sprays into the nose.

Flu Vaccines Are Contraindicated In:

• People who have severe allergic reactions.

• Outside the age range.

• Pregnancy.

• Asthma.

• Allergic to any constituent of the vaccine.

• Recent antiviral drug use, etc.

Why Should One Take a Flu Shot?

The protection given by flu vaccine varies from season to season, depending on age, health status, country, etc. The following are the reasons to get an influenza vaccine year after year.

• Flu vaccinations prevent millions of illnesses.

• It is proven to be life-saving in children.

• It safeguards women during and after pregnancy.

• Although it is not completely effective, it can reduce the severity of illness.

What Are the After effects of the Flu Shot?

Some of the common side effects include:

• Redness, soreness, and lump at the site of injection.

• Headache.

• Fever.

• Nausea.

• Muscle ache.

• Life-threatening reactions are infrequent.

• Signs of severe allergic reactions include wheezing, hives, shortness of breath, fast heartbeat, dizziness, etc.

• There is a slight chance of the flu vaccine and its association with Guillain barre syndrome (1 case per million people).

Can a Person Still Get Sick After Taking a Flu Vaccine?

Yes, some people still get sick even after taking flu vaccines. The reasons are:

• Some people confuse other respiratory viruses with the flu virus and may get other symptoms similar to the flu.

• Another reason is when someone catches flu viruses just before or two weeks after vaccination. This exposure may make an individual sick.

• Some people might get a different virus than the one vaccinated.

Conclusion

Influenza vaccines are safe for anyone above the age of six months. While various antiviral therapies are available, influenza vaccination is the mainstay for preventing the disease and reducing the health burden. Vaccination administration can vary depending on age, health, and severity. Flu shots can be administered as injections (upper arm or thigh) or nasal sprays. Although it is not a hundred percent effective, it reduces the risk of developing severe complications.