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© Aaron Tilley and Kerry Hughes


© Aaron Tilley and Kerry Hughes

Why the humble egg is a key ingredient of some vaccines.

You can’t make a flu vaccine without a few eggs – up to 360,000 a day, in fact. Come inside pharmaceutical company GSK’s vaccine factory to discover why tens of millions of eggs are needed each year to stop the flu virus in its tracks.

Special thanks to GSK.


A vaccine is a very simple means to train your body and to prevent it from being infected by a bacterium or a virus.

We are manufacturing here on this site influenza vaccines – seasonal and pandemic influenza vaccines.

We get these eggs from about 14 different farms, spread all over Germany and right into the Netherlands as well.

The manufacturing process of our influenza vaccines starts with the inoculation of the influenza virus into the eggs, followed by an incubation at well-controlled temperatures under well-controlled conditions.

During that incubation phase, the influenza virus is multiplying.

In the second stage now, we harvest the allantoic fluid from the eggs. This allantoic fluid now contains millions and millions of copies of influenza virus.

In the next stage, we purify the virus from the allantoic fluid and we also split the virus into small particles and inactivate it chemically in order to prevent it from being able to further replicate.

In the fourth stage, we sterile filter to yield a sterile suspension of purified influenza split virus with each of the four influenza strains we receive from the WHO reference laboratories, in order to formulate a quadrivalent vaccine containing two B strains and two different A strains as a base composition for this vaccine.

The manufacture of our bulk antigen takes us about 30 days, followed by another 30 days necessary for the formulation, filling, packaging of the vaccine.

Our whole manufacturing process and the success of what we are doing depends on the people we have.

This year we will produce approximately 50 million doses of influenza vaccine, delivering a very safe product which is able to protect people from serious infections.

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