No, you cannot get flu from a vaccine: here’s why

Gary Finnegan

Gary Finnegan

December 6th, 2016

Gary Finnegan

‘Flu vaccines are made using flu viruses. But there’s a simple reason that they keep us healthy without giving us the flu. The virus in the vaccine has been killed. ’

When scientists are making the annual flu injection, they use heat or other processes to ‘inactivate’ the virus. This means it cannot infect us. Thanks science!

As this video explains, there is an enduring myth circulating online that suggests the (inactivated) vaccine could cause the flu. This is simply not the case – watch the animation to see why.


One reason this myth can feel true (in spite of the facts) is that it can take several days after vaccination before we become immune to flu viruses.

So, if someone has the vaccine on a Monday and then feels ill on Tuesday, it’s natural to jump to the conclusion that the jab didn’t work or that it caused the flu. This is an example of how our instincts let us down.

The vaccine cannot give you the flu. If you develop the flu a day or two after vaccination it’s because your body hasn’t had time to develop immunity in response to the jab.

Like all vaccines, the flu jab can have side effects. The most common unwanted effects are soreness and swelling in the area where the vaccine was injected. This is not pleasant, but it is nothing compared to the misery of catching the flu virus.

The most common effect of the flu vaccine is protection from flu viruses.

Take a look at this video if you want to know a little more about how thousands of scientists around the world, coordinated by the WHO, help to decide which viruses go into the annual flu vaccine.

Doctors and researchers in 110 nations – most likely including your country – collect samples from patients (like you!) and send them to national laboratories. Experts in these centres analyse the samples to see which flu viruses are circulating in our communities.

This information is shared with the WHO. Then, twice a year, experts come together at the WHO headquarters in Geneva, to decide which viruses should be included in the annual vaccines.

The reason they meet twice as year is because the content of the vaccine is reviewed after the flu season in the northern hemisphere and then again after the flu season in the southern hemisphere. (Almost nobody gets flu at Christmas in Australia – because it’s summer time.)

This system has been in place for 65 years, helping to reduce the impact of annual flu outbreaks and ensuring health authorities are ready to respond to crises such as the 2009/2010 H1N1 flu pandemic.

More questions? Ask below.

Note: The video above refers to the injected vaccine which is inactivated. The Live Attenuated Influenza Vaccine (LAIV) used in some countries as a nasal spray is made from a weakened flu virus – and does not cause flu.


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