Understanding Vaccines

Vaccines: Against every virus and infectious disease, the arrival of the vaccine always serves as a beacon of hope. Vaccines always serve as a form of protection against numerous viruses, ranging from the annual common flu to the Ebola vaccine. How do vaccines function? And what are the different types of vaccines?

Illustration of scientists manufacturing a vaccine (Time) by Peter Greenwood

How does a vaccine work?

A vaccine has a single purpose: to train our immune system to recognize pathogens. Once the immune system has been trained to recognize the pathogen, it can later attack that same pathogen if it reenters our body. To do so, vaccines contain a version or part of the pathogen. Vaccines are primarily composed of:

• Antigens: This is the infectious part of the pathogen- the carrier of the disease. This helps in training the immune system to recognize the harmful pathogen.
• Adjuvants: This promotes the immune systems response, making the body react even more to the pathogen.
• Stabilizers: They continue to stabilize the vaccines even after the latter are shifted and transported to various locations.
• Preservatives: These protect the vaccine from pathogens that threaten the safety of the vaccine (typically other pathogens, such as fungi).

Once the components of the vaccine have entered the body, the immune system will begin to attack the pathogen. Initially, the immune systems attack against the pathogen may be weak. However, if the person is exposed to the pathogen once more, the immune system recognizes the pathogen and will attack it.

What are the types of vaccines?

There are a few main types of vaccines that are used widely in our current society (though there are also countless others):

• Live attenuated vaccines: These are the vaccines containing the live, yet weakened version of the pathogen. These generally, due to the fact that the pathogen is live, provide the patient with long amounts of time with immunity. However, due to the same reason, people who are more susceptible to the infection must be cautious when utilizing the vaccine.
• Inactivated vaccines: These are the inactivated ('dead') versions of the pathogen. Whilst vulnerable people may not have to be wary around these types of vaccines, due to the pathogen being inactive, the immunity is generally short.
• Toxoid vaccines: As opposed to protecting the person against the pathogen as a whole, in the toxoid vaccine, the antigens are the disease-causing part of the virus. Therefore, when this antigen enters the cells, the immune system is triggered specifically by the harmful part of the pathogen.
• mRNA vaccines: These vaccines utilize the mRNA (messenger ribonucleic acid) of the pathogen. RNA vaccines trigger the synthesis of the pathogenic protein within the patient's cells. This is because the RNA of the pathogen contains the genetic information that helps in protein synthesis. By using solely the pathogenic mRNA, the risk of infection is minimal whilst the body can trigger its immune response.

Therefore, vaccines are a major foundation in human health, especially with the discovery of novel viruses and other pathogens. Even though we still have multiple mysteries to solve- such as finding a universal influenza vaccine and a HIV vaccine- we must acknowledge that we have progressed far in the field of immunization. One of the main things that all of us should do is educate others about the importance of vaccines and debunk any conspiracies about them.