How Does COVID-19 Vaccine Work And How Long Is It Effective?

Before understanding how the COVID-19 vaccine works, let us briefly understand what COVID-19 is and how it has become a global pandemic. In order to fight the disease, we must recognise the symptoms of the virus first and then test and get a better understanding of what we are up against.

What is COVID-19?

Novel coronavirus is a new strain of coronaviruses (CoV) which is a large family of viruses that infects the body and causes a wide range of respiratory illnesses. The infection may be mild like a common cold, dry cough, fever or it could be more severe like Severe Acute Respiratory Syndrome (SARS-CoV) and Middle East Respiratory Syndrome (MERS-CoV). It is highly contagious and 20% of coronavirus cases are asymptomatic which means that it goes unidentified yet the carrier can pass the virus to another person if exposed. When a person is infected with COVID-19, the virus multiplies in the body and its spiky surface protein latches onto the receptors of healthy cells and hijacks them, therefore, taking command over them.

How does the vaccine work?

When you are injected with the COVID-19 vaccine (or any vaccine), there is a supply of B-lymphocytes and T-lymphocytes that are left in the body. Macrophages are the white blood cells that swallow and digest the virus that has infected the body. They leave behind pieces of the virus that the B-Lymphocytes (defensive white blood cells) attack. The T-lymphocytes (another type of defensive white blood cells) attack the cells that have already been attacked in the body. Therefore, the vaccine helps load the body with the two types of defensive white blood cells to aid in building immunity against the infection as well as to fight the same infection in the future. It typically takes a few weeks to initiate the production of these lymphocytes which is why it is possible to get infected with COVID-19 just before or after taking the vaccine. The vaccine in itself can cause some of the symptoms of the virus like fever and body ache as a part of the immunity building procedure. Some vaccines like the Pfizer-BioNTech and Moderna vaccine will require 2 doses of the vaccine while other vaccines like the Johnson and Johnson’s Janssen vaccine only require one shot. You are considered as fully vaccinated only once it has been 2 weeks since receiving the final shot. Hence, it is recommended that even a vaccinated person should follow COVID-19 appropriate etiquette for at least 2 weeks after the final dose of the vaccine. 

How long is the vaccine effective? Will I need to take it every year?

The entire development process of a vaccine is a long duration and ideally takes anywhere between 10-15 years of testing and production. From the initial exploratory stages to all the testing phases and the VAERS (Vaccine Adverse Event Reporting System), it takes a long period of time to completely develop a safe and effective vaccine that is authorised to be injected into the body. However, COVID-19 pandemic has become a global emergency which has put the strength of our modern medicine and technological advancement to the test. Due to the short duration of testing and experimenting, experts are saying that the vaccine should protect the body for at least 6 months after the second dose but they will require more time and testing to see if its effectiveness will wane away and if regular doses of the vaccine need to be administered. The novel coronavirus is a very new and unfamiliar virus that took the world by storm and it has been challenging for all the vaccine experts to formulate a vaccine in such a restricted period of time. On saying this, the medicine industry has managed to take the first step in the right direction to win this battle against COVID-19.