VACCINES – How do they work?

Vaccines are a proven way of preventing disease. Through vaccination programmes, humans have managed to eradicate poliovirus and smallpox successfully. But how does vaccination work? To understand that, it is essential to know how the body’s immune system protects us against disease.

Vaccine awareness

Immune System – Our Body’s Natural Response to Fight Infection

The immune system is a network of cells, organs and tissues that work together to help fight off infection from virus, bacteria and fungus. When a pathogen (disease-causing organism) invades your body, your immune system recognises it as a foreign body and triggers a response to destroy it.

Each pathogen is made up of several subparts, known as an antigen that causes the formation of antibodies. We have thousands of different antibodies in our system that are trained to recognise one specific antigen. When a human body is exposed to an antigen for the first time, it takes time for the immune system to respond and produce antibodies specific to that antigen.

In the meantime, if a person is susceptible to a harmful organism, it can lead to illness or death (in extreme cases).

Once the body produces antibodies, it also creates antibody-producing memory cells, which remain alive even after the pathogen is defeated. Hence, if the body encounters the same pathogen years later, the antibody response is much faster and more effective than the preceding time because the memory cells are ready to pump out antibodies against that specific antigen.

Antibody working against virus

How vaccines help

Vaccines contain an inactive or weakened form of a particular virus that triggers an immune response within the body. This weakened version of the virus will not cause the disease in the person receiving the vaccine, but it will prepare their immune system to respond as quickly as it would have been on its first reaction to the actual pathogen. However, some vaccines require multiple doses, given weeks or months apart. The time gap is sometimes needed to allow for the development of memory cells and the production of long-lived antibodies.

How vaccines work

Community Immunity

Vaccines don’t just work on an individual level, but also protects the entire population. Once a large amount of the population is immunized, opportunities for an outbreak decrease. Therefore people, who cannot be vaccinated due to their compromised immune system, are still protected. A bacteria or virus won’t have enough hosts to circulate and eventually get eradicated as most of them are immune. This process is known as community immunity or herd immunity. And it has allowed life-threatening diseases to be eliminated entirely without needing to vaccinate every individual.

Vaccine protects an individual
Herd immunity

Learning so much about vaccines is great, but you know what is better? Getting vaccinated! Hope you’re observing all COVID-19 related safety measures, and of course, getting your vaccine shot.