Vaccinations

In today’s world, with the COVID - 19 pandemic being an evident part of our lives, vaccines are one of the first things that will come to your mind concerning this Global Pandemic. Vaccines have not only been used for COVID -19 but have also played a vital role in the growth and development of every human body. To know more about: what vaccines are about, the types of vaccines, and how they work in our bodies, continue reading this article.

What are Vaccines?

Vaccines are biological compositions produced in laboratories that provide acquired immunity to prevent the human body from being infected by dangerous diseases. Vaccines also reduce the risk of getting infected by coordinating with the human immune system to provide resistance against various infectious diseases. The process of getting the accurate number of doses of a particular type of vaccine is known as vaccination. Once a person acquires immunity to a specific vaccine, they are considered immunized or vaccinated. Vaccines have proven to be very advantageous due to their ability to prevent infectious and non-infectious diseases.

Different Types of Vaccines

There are significant factors that scientists consider before moving forward with creating vaccines. One of them is the response of the human body to a vaccine. Based on several other factors, scientists broadly categorized vaccines into:

Inactivated Vaccines: These vaccines are developed from the pathogen that causes the disease itself, usually the blighted version of the pathogen. They fail to provide extensive immunity compared to living vaccines, due to which the number of doses of inactivated vaccines is usually more, about 2-3 doses. Since inactivated vaccines are made from dead pathogens, they will not cause the infection.

Live (attenuated) Vaccines: Live vaccines are made from living (attenuated) microbes. Since they are significantly similar to the infection, they develop successful immune responses. Therefore, a finite number of doses of this vaccine can guarantee protection against a particular disease for a long time, sometimes even for a lifetime. However, live vaccines may not be effective for people whose immune systems can't work due to certain medical conditions or drug allergies. Another disadvantage of live vaccines is that they may cause the disease itself due to living forms of bacteria and viruses, which can multiply in the bodies where the immune system is weak.

Comparison between Inactivated and Live Vaccines

A study conducted between 2015-2016 compared the two types of vaccines for a respiratory condition known as influenza in children in the United States.

During this period, both the live (attenuated) influenza vaccine [LAIV] and the inactivated influenza vaccine [IIV] were available in the United States.

In this study, children between the ages of 2 to 17 were kept under ambulatory care. Their respiratory system was monitored for five days at eight different sites across the country for five months, between 30th November 2015 and 15th April 2016. Nasal swabs were taken for conducting a specific test called reverse - transcriptase-polymerase chain reaction or (RT - PCR) for influenza disease. The children were split into three groups: those who received the live vaccines [LAIV], those who received the inactivated vaccines [IIV], and the control group who didn’t receive vaccinations.

Among 1012 children who were kept back for the analysis, 59% were unvaccinated, 10% received LAIV and 31% received IIV. Influenza A was detected in 14% and influenza B was 10%. For all types of influenza, vaccination effectiveness was 46%, for LAIV it was 42%, and 65% for IIV.

In conclusion, both LAIV and IIV vaccines showed effective results for influenza. Overall, we can see that vaccination effectiveness was significantly higher in inactivated vaccines than live vaccines when compared to the unvaccinated children.

How do vaccines work?

Vaccines help develop immunity by copying the disease or infection. However, this type of infection never harms the body but helps the immune system in producing T-lymphocytes and antibodies. During the process of generating antibodies, there could be a possibility of developing some negligible symptoms such as fever and body ache.

Once the copied form of the infection is destroyed by the body, the antibodies register the characteristics of the infection in the memory cells. Which is remembered by the body when it is infected with the same infection again.

Nevertheless, after vaccination, it generally takes a couple of weeks for the body to develop T-lymphocytes and B-lymphocytes. During this period, from receiving the vaccine to developing antibodies, there are chances that the person can get infected because the immune system has not developed antibodies as yet and therefore cannot provide protection.

By Shreya Balasubramaniam