Will the Influenza Vaccine Make You Sick?

Whether you choose to get it or not, being informed is a good thing

Virology Blog

Vaccine basics

When an infectious agent enters the body, its goal is to start replicating and making more of itself. Your immune system wants to shut that down. There are several layers to the immune response, and a key element is the production of antibodies. These are Y-shaped proteins your body makes that are specific to that infectious agent. They latch onto it and sort of wrestle it to the ground so that other components of the immune system can go to town.

The influenza vaccine

The diagram above shows an influenza virus. The squiggly bits in the middle are the viral DNA, which is what gets you sick. That’s contained within a capsule, which has various proteins sticking out of it (the purple and gold coloured bits).

There’s no viral DNA contained in the vaccine, and the DNA is what makes you sick, so the injectable flu vaccine can’t possibly give you the flu. There’s simply no biological mechanism for this to happen.

The nasal spray formulation of the flu vaccine is different. It contains live weakened virus. It’s not going to make people with a healthy immune system sick, but people who are immunocompromised or on immunosuppressant medications can get sick, so it’s generally recommended that they avoid live vaccines.

What’s good and what’s not about the influenza vaccine

Let’s start with the bad.

Those immunocompromised people who shouldn’t take the live virus nasal spray vaccine? If they catch the flu, it could actually kill them.

Same with the elderly. People with chronic respiratory conditions can also have significant complications from the flu. These are the people that need protecting, and that’s why getting vaccinated is important.

What if you get sick after the vaccine?

One option is that when your body is generating the immune response that it’s supposed to, you may feel a little under the weather. This isn’t an infection, it’s your body doing its thing.

Mental health blogger | Former MH nurse | Living with depression | Author of 4books, latest is A Brief History of Stigma| mentalhealthathome.org