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The history of the flu vaccine

Approved by our Clinical team | Aug 25, 2021

The flu vaccine is an annual jab that’s free on the NHS for certain groups of people, including the over-50s and pregnant women. It’s also available privately from pharmacies, including our stores, for anyone over the age of 18.

People who are more likely to get seriously ill from the flu need to get the vaccine every year. This is because every year there are different strains of the flu virus circulating around the UK. It’s also a good idea to get a flu jab annually even if you don’t have a health condition as it can help protect you and those around you from the flu.

When was the flu vaccine invented?

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In the 1930s, two different types of the flu virus were isolated – type A and type B. The same decade, researchers discovered that they could grow the flu virus in hens’ eggs, allowing them to study it more closely and develop an inactivated vaccine.

In 1942, a vaccine offering protection against influenza A and B viruses was developed using fertilised hens’ eggs. Three years later, in 1945, the first inactivated influenza vaccine (IIV) was licensed for use by ordinary people – having been previously tested on the army.

In 2003, a second type of vaccine known as live, attenuated influenza vaccine (LAIV) was released. This type is also made using hens’ eggs, but is designed to be sprayed directly into the nostrils rather than injected. This type was developed for children, and contains a weakened – rather than inactivated – form of the flu virus.

In 2012, a cell-cultured version of the IIV was developed. This type uses animal cells as a host for growing the flu virus, rather than fertilised hens’ eggs. A year later, in 2013, a recombinant influenza vaccine (RIV) was released. This type uses recombinant technology that doesn’t require the use of hens’ eggs.

How is the flu vaccine made?

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There are many different types of modern flu vaccine, but they all work in a similar way: by preparing your body to fight off the strains of the flu virus that you’re most at-risk from.

Injected forms of the virus (those given to adults) don’t contain any live virus, and you can’t catch the flu by having a flu jab. Most types are still made using fertilised hens’ eggs, however some are made in a different way, which means they’ll be suitable for people with an egg allergy.

The nasal spray vaccine (the type given to children) is made using weakened versions of the virus. This type is developed in hens’ eggs and made using pork gelatine, so it won’t be suitable for everybody.

How does the flu vaccine work?

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Each year the World Health Organization makes recommendations about which flu strains will be prevalent in different parts of the world that coming flu season. Using this guidance, manufacturers of the flu vaccine develop a new vaccine for that year, designed to offer the highest level of protection.

When you get the flu jab at the beginning of the flu season, it “arms” your body against specific strains of the virus that are expected to be widespread over the next few months. This means your body will be more successful at fighting off those strains if you’re exposed to them.

You can still get the flu after having the jab, but if you do your symptoms should be milder and last for a shorter time than they would normally.

Because the vaccine changes every year, you’ll need to get your flu jab at the start of every flu season to ensure you remain protected.

When should I get the flu vaccine?

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In the UK, the flu is most prevalent during the late autumn, winter, and early spring.

To make sure you’re protected, you should get the flu vaccine in the early autumn before the virus starts to circulate. You can get it later on, but waiting will increase your risk of catching the flu.

As a note, the flu vaccine takes about 10 to 14 days to work. Before this time, you might still be vulnerable to infection and illness.