Employee Wellness Blog | TotalWellness

The Science Behind Flu Vaccines: A Simple Guide

Written by Lisa Stovall | Tue, Sep 03, 2024

Every fall, as the leaves turn golden and the chill creeps into the air, a familiar foe emerges — the flu.

This unwelcome guest doesn’t just throw a wrench in our daily routines; it can seriously impact our health. But we’ve got a secret weapon in our arsenal: the flu shot. It’s time to dive into what makes this tiny jab such a mighty protector and why it’s your best bet against the flu’s yearly invasion.

Think getting a flu shot is just another item on your to-do list?

Think again.

That little shot is a superhero in disguise, working tirelessly to keep you and your loved ones safe and healthy. The flu virus is a master of disguise, changing its form every year, which is why a new vaccine is rolled out each season.

So, what’s the deal with flu shots? Let’s unravel the science behind them and discover why this annual ritual is more important than you might think.

What is the Flu Vaccine?

The flu vaccine was developed for the US military during the 1930s and 1940s. In 1945, the first flu vaccine was approved for use by civilians, not just military personnel.

Today, it is considered safe and effective for anyone six months or older. Flu shots protect against influenza, a contagious respiratory virus that can lead to severe illness and complications. But how do these microscopic guardians defend us? When you receive a flu shot, you’re introducing inactivated or weakened flu viruses into your body. This doesn’t cause the flu but does trigger your immune system to produce antibodies. These antibodies are like your body’s own personal security team, trained to recognize and fight off the actual virus if you’re exposed to it in the future.

The flu vaccine is like a shield for your body. It helps protect you from getting sick with the flu, a virus that can make you feel terrible and sometimes even lead to serious health problems. Scientists work hard every year to create the flu vaccine by studying which flu viruses are likely to spread. 

Different Types of Flu Vaccines

For over 70 years, the egg-based manufacturing procedure has been the go-to method for creating influenza vaccines. This technique produces two types of vaccines: inactivated (killed) vaccines, which are known as the “flu shot,” and live attenuated (weakened virus) vaccines, which are commonly known as the “nasal spray flu vaccine.”

The flu virus is a master of disguise, constantly changing its appearance to evade our immune defenses. This is where the science of flu vaccines truly shines, as researchers work tirelessly to anticipate these changes and update the vaccine composition each year. There are several types of flu vaccines available, each designed to offer protection:

There’s more than one kind of flu vaccine, and each one is made to fit different needs:

  • Standard Flu Shots: These are the most common and work for most people. They protect against several types of flu viruses.
  • High-Dose Shots: These are made especially for older adults because their bodies might need extra help to fight off the flu.
  • Nasal Spray Vaccines: If you don’t like needles, this might be for you. It’s a spray that goes in your nose and is available for people aged 2 to 49.
  • Egg-Free Vaccines: Some people are allergic to eggs, so there’s a special vaccine made without eggs just for them.

Influenza Vaccine Composition for 24-25 Season

The flu virus is a bit tricky because it’s constantly changing. The vaccine you got last year might not work as well this year because the virus has changed. That’s why getting a flu shot every year is essential to keep your body ready to fight off the newest flu viruses.

This year marks a change in flu vaccines in the United States. For the last ten years, flu vaccines have been quadrivalent, meaning they protect against four different strains of the flu virus. But in 2024, there's a shift happening — moving from quadrivalent to trivalent vaccines.

Why the change? The reason lies in the flu virus itself. Since March 2020, the influenza B/Yamagata virus, one of the components in quadrivalent vaccines, has not been detected in global surveillance. With no signs of this virus, health experts have removed the B/Yamagata component from the flu vaccine, simplifying it to a trivalent vaccine.

This transition is based on careful monitoring and science-driven decisions, ensuring that the flu vaccine remains as effective as possible against the viruses that are out there. The updated trivalent vaccine will continue to provide vital protection, targeting the most relevant and active flu strains.

The World Health Organization (WHO) convenes biannual meetings to suggest the viral composition of influenza vaccines for each influenza season in the northern and southern hemispheres. The WHO recommends that trivalent vaccines for use in the 2024-2025 northern hemisphere influenza season contain the following: 

Egg-based vaccines:

  • an A/Victoria/4897/2022 (H1N1)pdm09-like virus;
  • an A/Thailand/8/2022 (H3N2)-like virus; and
  • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.
Cell culture- or recombinant-based vaccines:
  • an A/Wisconsin/67/2022 (H1N1)pdm09-like virus;
  • an A/Massachusetts/18/2022 (H3N2)-like virus; and
  • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.

The Future of Flu Shots 

It looks like combined COVID-flu shots are on the way. Moderna's latest mRNA vaccine has passed a major test, showing that it offers better protection against both COVID-19 and the flu compared to traditional single-target vaccines. The drugmaker aims to launch this innovative shot just in time for the fall respiratory disease season in 2025. As we look to the future, these combined vaccines could become a game-changer in our fight against seasonal illnesses.

A Safe and Healthy Choice

Flu vaccines have been around for a long time and are very safe. They’re designed to keep you and everyone around you healthy. So, when you get your flu shot, you’re not just protecting yourself but also helping protect your family, friends, and coworkers.

Getting a flu shot each year is a simple and important way to stay healthy. It’s one small step that makes a big difference!

Protect Your Team with TotalWellness

As we gear up for another flu season, now is the perfect time to take action. Protecting your workplace from the flu is easier than ever with TotalWellness. We offer convenient on-site flu shot clinics that make it simple for your employees to stay healthy and productive all season long.

Don’t wait until the flu starts spreading — schedule your flu shot clinic with TotalWellness today! By bringing the flu shot directly to your team, you’re taking a proactive step in safeguarding their health and well-being. Let’s work together to create a healthier, happier workplace this flu season.

Ready to make it happen? Contact TotalWellness now to set up your clinic and give your team the protection they deserve.