Vaccines: An Overview

To say that vaccines have changed civilisation is an understatement. Asked to name the most important contributions from the medical field, most public health professionals would struggle not to have immunisation at the top of the list. Vaccines have been a game-changer.

The gasping breath of a baby with whooping cough; the intimidating iron lung and braces built for those with polio; the crushing birth defects caused by rubella: these devastating infectious diseases were once the main culprits for an infant and child mortality rate of 20 percent in the US.

Fortunately, in industrialised nations where vaccines are widespread, safe and effective, these scourges are mostly associated with the past. As you’ve no doubt heard from health professionals in just about every field, preventative medicine is the best medicine, and that’s what vaccines are all about.

So, how exactly do vaccines work? Let’s take a look.

How do vaccines work?

Vaccines do their job by training the immune system to recognise and fight certain pathogens from either bacteria or viruses. They do this by introducing particular molecules from the pathogens into our bodies so that an immune response is triggered.

These molecules are called antigens, and all bacteria and viruses have them. These antigens are basically little signs that help the immune system recognise the pathogen and execute the proper response, so the next time it’s exposed to the pathogen it knows what to do.

If a vaccine contains parts of a virus or bacterium, then why don’t they make us sick?

This is the trick of vaccines. We have to expose a person to a particular pathogen so their immune system can develop an immunity to it without making them sick. Several methods have been developed that achieve this, leading to multiple types of vaccines. Let’s have a look at them.