Now we are going through the COVID-19 pandemic situation with the only hope of vaccine. Whenever we think about the vaccination, several issues arise in our minds. How does the vaccine work? What is the defensive system of the human body? How these two works together to protect us from any viral infection? How do the vaccines develop? What is the basis of this development? Let’s, try to explore the issues with COVID-19 vaccines.
The immune system of the human body is nothing but a complex network of cells and proteins that take protection against any viral attack. In general, the immune system keeps track of earlier infections, microbes (germs) so that it can recognize and defeat the germs from future attacks/infections. However, different autoimmune disorders, immunodeficiencies, and allergic diseases can be occurred due to abnormalities of the immune system.
To understand the working strategy of COVID-19 vaccines, first, try to understand the protection system of our body or how it fights illness. When the disease-causing virus enters into the host, invades into the body, attack and replicate. This invasion causes illness in host, referred to as viral infection. The immune system utilizes different organs to fight against infection. Blood is one of the key elements in this work. Specially the White blood cells (WBC) fight against viral infection. Initially, the histiocytes of WBC try to digest the microbes and the dead cells. The substances left by a virus that causes an immune response in the host cell are known as an antigen. These antigens are dangerous for the host. The B-lymphocytes produce antibodies to attack these antigens. The other defensive component of WBC is T-lymphocytes which are responsible to attack the already infected cells.
The immune system is like a learning model, which took several days at the first attack to fight against the virus and get over the infection. After the infection, the immune system remembers the fighting strategy and gain knowledge from this learning in the form of T-lymphocytes (memory cells of the immune system). In the future, if the host encounters a similar type of antigen due to viral infection, it identifies these through T-lymphocytes and B-lymphocytes produce the antibody to attack those familiar antigens.
Several experiments are going on to find how long this memorization can help the host body to protect against the novel Coronavirus (SARS-COV-2). mRNA-based vaccines have been considered a recognized solution for decades. These vaccines are advantageous over other traditional approaches because they took a short development phase and they can be devised in the laboratory with easily acquirable materials.
Although mRNA-based vaccines have been studied and utilized for cytomegalovirus, rabies, and Zika virus. Scientists have built unique spike protein into the mRNA vaccine for COVID-19 treatment. The mRNA vaccine helps in triggering the immune response inside the human body by entering the piece of viral protein or instructing the cell to make the viral protein. Unlike mRNA-based vaccines, several
vaccines put inactivated or weakened microbes in the host body to trigger the immune response. Instead, the mRNA vaccine teaches the host cells how to produce a part of a harmless protein or a complete protein that can activate the immune system. While identifying these proteins, the immune system produces the antibody to protect against the infection in the host body.
The mRNA-based vaccine does not use the live disease-causing virus. It does not have any adverse effect on DNA, even no possibility of interaction with DNA as mRNA never enters into the cell nucleus. Once mRNA completes its task within the body, the cells break down and get relief from it.
Several advanced research is going on mRNA-based multipurpose vaccine development which can allow one vaccine to protect multiple viral infections. Moreover, cancer research has introduced mRNA based approach to triggering the immune system against targeted cancer cells of patients.