Initial phases of germs entering the body

We have good and bad germs all around us, in our bodies and in our environments. Unfortunately, when a person is vulnerable and they meet a ‘bad germ’, or harmful organism, it can lead to disease and sometimes death. These harmful organisms are called pathogens.

Our bodies are equipped with many way of defending itself against pathogens, our skin, mucus and cilia (these are tiny microscopic hairs that remove debris away from the lungs), all work as physical barriers to prevent pathogens from entering the body in the first place. When a pathogen manages to get into our bodies, our bodily defences (the immune system) is triggered and the pathogen is attacked and destroyed, or overcome.

Antibodies – a natural response

A bad germ – pathogen is a virus, bacterium, parasite or fungus that can cause disease within our bodies.

A pathogen is made up of several subparts, which tend to be unique to specific pathogen and the disease that it causes. Within the subparts is a thing called an antigen, this causes the creation of antibodies.

During the Covid-19 outbreak, you might have heard the word antibodies flying around a lot?

Antibodies in our bodies are produced in response to the pathogen’s antigen, and these are an important part of our immune system.

Figure 1 – Antibodies defending. (Getty images)

Think of antibodies as soldiers for your bodies defense line, each antibody, or soldier, is trained to recognise one specific antigen.

We have thousands of different antibodies in our body. When we are exposed to an antigen for the first time, the immune system takes time to respond and produce antibodies (soldiers) for that specific antigen.

Unfortunately, in the meantime, the person is vulnerable to becoming ill.

Once the new antibodies are made for that specific antigen, they work with the rest of the immune system to destroy the pathogen (bad germ) and stop the disease.

Did you know, that once our body has created antibodies in the first response to the pathogen, it also makes antibody-producing memory cells. These cells stay alive even when the pathogen has been defeated by the antibodies.

This means that if the body is exposed to the same pathogen more than once, the antibodies will respond much faster and more effectively than the first time around.

This is because the memory cells are ready and waiting to pump out antibodies against the antigen.

This means that if the person is exposed to the dangerous pathogen in the future, their immune system will be able to respond immediately, protecting against disease.

The role of a vaccine

Vaccines have a weakened or inactive part of the antigen that would trigger the immune response in the body. Newer vaccines have the blueprint for producing antigens, rather than the antigen itself.

Regardless of which vaccine you have, the weakened version of the antigen won’t cause disease in the person receiving the vaccine. But, it will encourage the immune system to respond, just like it would if being ‘invaded’ like the first reaction to the actual pathogen.

Sometimes you need multiple doses of a vaccine, this could be weeks or months apart. This helps our bodies to fight the specific disease causing pathogen by building up the long-lived antibodies (soldiers) and to develop memory cells.

This way, the body will be able to rapidly fight the invader when exposed in the future.

Herd immunity

Herd immunity is another phrase you might have heard during the Covid-19 pandemic, let’s explain it!

When we have a vaccine, we’re likely to be protected from that specific disease. Unfortunately, not everyone can have be vaccinated. People who have underlying health conditions that weaken their immune system (such as HIV or cancer) or those who have severe allergies to some of the ingredients in the vaccine, might not be able to have certain vaccines.

Luckily, these people can still be protected if they live in and around others who are vaccinated.

But how??

When lots of people within a community are vaccinated, the pathogen (bad germ) finds it hard to go around, this is because most of the people it meets are immune. So, the more people that are vaccinated, the less likely people who are not able to have vaccine to protect them are at risk of even being exposed to the harmful pathogen.

This is called herd immunity.

Herd immunity is particularly important for those people who not only can’t be vaccinated, but they might also be more vulnerable to the diseases that we have vaccines for.

No vaccine provides 100% protection, and a herd immunity also doesn’t provide full protection to those who can’t be vaccinated – but with herd immunity, these more vulnerable people will have substantial protection, thanks to those around them being vaccinated!

So in short, vaccinating not only protects yourself, but also protects those in the community who are unable to be vaccinated.

I hope this blog post has helped you to understand vaccines a little bit more & how they work in our bodies. Join us again tomorrow where we’ll be discussing the myths and truths of the Covid-19 vaccine info.

If you have any specific questions about vaccines, or specifically the Covid-19 vaccine, why not join our free Q&A session on Friday 5th February with a medical professional.

If you’d like to join and send in your questions beforehand, please email by 12:30 Thursday 4th February.

Meeting ID: 859 7517 4054 Passcode: 12345


World Health Organisation. (2020). How do vaccines work?. 


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