Jesse McNamara
Expert: Consultant

As a consultant analyst Jesse has spent almost 2 years working with some of Australia's largest organisations. Prior to joining 460Degrees, he completed a Master of Biotechnology and worked overseas researching childhood liver cancer.

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August 21, 2020

How do Vaccines Work?

Hands up who’s been vaccinated before? Your kids, pets, someone you know perhaps.

There’s a reason we get these unpleasant little jabs – it’s because they work, according to scientific research. And they protect us. And our kids. And our pets, grandparents, neighbours, everyone. And that is a very good thing.

No doubt we are all wishing for a COVID vaccine to be approved sooner rather than later so life can go back to what we all knew as ‘normal’.

But has anyone ever wondered how vaccines work? Well, I am your man. Let’s step away from the business talk for a while and dive into some science.

How do Vaccines Work?

Vaccines are like a really good coach. Yep, a coach. But how does that make any sense? Well, they train our immune systems to recognise pathogens (viruses and bacteria – the bad guys) so that when we encounter the real thing we are able to kill it. That’s right – we do the killing, not the vaccine.

Our immune system is made up of two halves. We have a half that responds to general infections, things such as cuts on the skin (hence a bit of swelling), or pollen in our nasal cavity (sneezing!). It consists of barriers such as skin and mucous and also a few types of white blood cells. It’s generally referred to as our “innate immune system” and it’s a rapid response unit with no real specificity, it just wants to kill anything it determines to be not part of ourselves. It’s uncomplicated pure thuggery. And it’s a great first line of defence. But sometimes it lets things through the gaps.

The other half of our immune system is referred to as “adaptive immunity”. This half is comprised of cells which are able to learn the specific patterns found on the surface of pathogens.

These trainable cells are known as T cells and B cells, and they’re our best friends. Living in our bodies at any one time, we will have at least one T or B cell specific to ANY virus or bacteria. Literally millions of these singular, incredibly specific cells (single and ready to mingle!).

A vaccine is usually, but not always, a broken up fragment of the protein coat of a pathogen. That’s all it is. This is what our T and B cells recognise. When the vaccine hits our bodies, these fragments run through our network of blood and lymph vessels and come into contact with all of these specific cells until they find THE ONE.

When this immune cell recognises it has a match, it rapidly divides millions of times, creating millions of identical clones, until there are enough to defeat the enemy. Although a vaccine is just a false alarm, heaps of these cells hang around in our bodies so that next time that specific fragment enters our bodies (this time as a whole pathogen!), the time taken to mobilise a response is literally within hours rather than days. This quick response time is why they work.

So that’s it in a nutshell.

If you want answers to more questions, like what’s the difference between a T and B cell? Or, how does a virus replicate and live and actually what even is a virus? Or anything else of the sort, feel free to comment below and I’ll drop some more knowledge.

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