Types of Vaccine
Vaccines are pharmaceutical suspension or solutions of immunogenic substances intended to induce active immunity. Types of vaccine: based on their preparation, vaccines can be classified as below: 1 Inactivated-killed vaccines – these are prepared by killing or inactivating the pathogens (bacteria, virus, fungus) using heat or chemicals, examples of such vaccines are typhoid, plague, cholera, whooping cough, rabies, influenza, hepatitis and polio virus. 2 Live attenuated vaccines – These vaccines are non-virulent microorganisms used to retain antigenicity, examples of these types of vaccines are: BCG, MMR, Polio Sabin. 3 Toxoids – They are prepared by the treatment of pathogenic (bacterial, virus) toxins with formalin examples of such vaccines are TT (tetanus toxoid), diphtheria. Let us come to the current situation and try to understand about the types of Covid-19 vaccines are undergoing trials: We all come across and affected by Covid-19 pandemic virus, scientists, Govt organisations, NGOs, private labs from every corner of this planet are working day and night to make effective vaccine for covid-19 and some of them succeeded and reach to final stage, the types of vaccines they are working on basically 5 types, they are either comes under above mentioned categories or their sub categories. 1 It’s first type of vaccine is a genetic vaccine, under which, immunity is developed in the body using the genes of corona virus. About a dozen companies and institutes are working on genetic vaccines. 2 The second type of vaccine is called Viral Vector vaccines. Under this, the Genes of Corona Virus are transported to the cells of the body and it is seen whether the body's immunity is activated against it. The vaccine being created by the University of Oxford works on this principle. At present, work on 8 such vaccines is going on all over the world. 3 The third type of vaccine is called protein-based vaccines, wherein, proteins of COVID-19 virus are used to activate the immunity in the body against the virus. Around 9 companies around the world are experimenting with it. 4 The fourth vaccine is termed as Whole-Virus Vaccine, under which a weak or non-active corona virus is injected into the body which starts working against it after recognizing it. The experiment is underway on 4 such vaccines across the world. Bharat Biotech and Indian Council of Medical Research (ICMR) are making similar vaccines in India and the human trial has started in AIIMS, Delhi. 5 The experiments are also underway on Repurposed vaccines, under which the vaccine that was already used for any other disease can also be effective against COVID-19. Work on one such vaccine is going on in the world.