How Do Vaccines Work?

With the COVID-19 vaccine moving quickly from research to millions vaccinated across the globe, many people have become interested in the way vaccines are developed. Of course, many of us have received vaccines for other diseases during our lifetime, with them playing an important part in protecting the human population from long-term sickness. As pharmaceutical distributors, we have played our part in ensuring the safe transportation of medical products with our expert services, and know the logistical challenges faced with mass-vaccination programs. So, how do vaccines work?

Research and Development of Vaccines

Put simply, vaccines are developed to help train the human body’s immune system to make it stronger in fighting disease or infection. Their purpose is to prevent disease before it happens, protecting the body from developing serious symptoms and harming the immune system. Once a vaccine is administered, usually via injection, the body will take time to adjust to the medicine and start to produce the right antibodies to fight certain diseases. Vaccines are developed for different types of disease as there is no one-size-fits-all vaccine that will protect you from everything you could potentially catch. An example of this is COVID-19, which a vaccine did not exist for before it became apparent it was widely spreading and becoming a global pandemic. It is also why you may have had separate vaccines for seasonal flu, measles, chicken pox etc. as they all require different antibodies to fight them.

Some diseases may have similarities, with COVID-19 part of a family of coronaviruses that include SARS, MERS, and the common cold, that present a starting point for developing a vaccine and begin rapid testing. As COVID-19 is a ‘novel’ or new coronavirus, for example, vaccine development needed to start from the research of its origins and other key areas including how it is transmitted. Finding out how pathogens, disease-causing organisms, infect the human body and how the immune system reacts to them is key at this stage. With the body’s natural response to fight these pathogens delayed if it has not encountered it before, this is when you can become ill as the body needs to produce a specific antigen which can take time. A vaccine is there to speed this process up so that the immune system can react immediately.

How do Vaccines Work - Preparing the Immune System

The vaccine needs to contain a fragment of the foreign antigen for them to work, and this a weakened or inactive part that helps to trigger the right immune response. Whilst having a small part of the disease it is trying to fight, this doesn’t cause the person receiving the vaccine to catch the disease. The only way the body can prepare itself is to sample some of this weakened antigen and then it can produce the relevant antibody if it ever has to fight the real organism.

Depending on the vaccine, some may require multiple doses to properly prepare your body’s immune system. This can be weeks or months apart and helps train the body to naturally produce the necessary reaction if it does encounter the virus or disease in future. The more people that receive a vaccine, the more protected the community becomes and can create herd immunity where the harmful organisms have nowhere to circulate easily and protect those who cannot receive a vaccine due to health issues.

Vaccines have helped humans overcome many harmful diseases throughout history and have prevented certain diseases that were once life-threatening, such as meningitis or polio, from becoming widespread. The quicker we learn about new types of harmful pathogens, the quicker the research is into developing the vaccine, providing a shorter window towards mass vaccination.

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References:

https://www.who.int/news-room/feature-stories/detail/how-do-vaccines-work#:~:text=Vaccines%20contain%20weakened%20or%20inactive,rather%20than%20the%20antigen%20itself.

https://www.immunology.org/celebrate-vaccines/public-engagement/guide-childhood-vaccinations/how-vaccines-work

https://vk.ovg.ox.ac.uk/vk/how-do-vaccines-work