The holy grail to fight pandemics such as COVID-19!

While it takes a few years of deliberate and careful work to develop a commercial vaccine, the COVID-19 pandemic has slightly changed the traditional vaccine development approach, writes Arti Dumbrepatil

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By Arti Dumbrepatil

Over three million people worldwide have been infected with COVID-19, the race for developing an empirical cure or vaccine for COVID-19 continues. This novel coronavirus, SARS-Cov-2, causes acute respiratory infection) not only changed the global perspective of healthcare but also challenged the thought process of every single individual. As a scientist, I have been asked multiple times by my friends and family (all coping with social isolation) about when will a vaccine against Covid-19 be ready? They have been constantly wondering why it is taking so long to develop a vaccine and, meanwhile how can they strengthen their immune system to fight infections like Covid-19? As a scientist and a science communicator, I decided to focus on effectively communicating the vaccine science to people and hope that it will help.

Immune system and Vaccines

The immune system, a vast network of cells, tissues, organs, and proteins is the body’s defense mechanism against infections. It is constantly on a lookout for invading foreign entities like bacteria, viruses, parasites, and more. It can distinguish our tissue from foreign tissue and also clears dead cells.

A vaccine is a biological preparation that imitates an infecting entity and triggers our immune system to make antibodies without causing illness in almost all cases. The immune system might take some time to develop an effective response after vaccination depending on the type of vaccine and how it is administered. In some cases, vaccines require more than one dose, to fight the potential infections. Scientists take several approaches to design and develop vaccines. There are mainly five types of vaccines: Live Attenuated Vaccines, Inactivated Vaccines, Toxoid Vaccines, Subunit Vaccines, and Conjugate vaccines. The approaches are based not only on the information available about the infection but practical concerns such as regions of the world where the vaccine would be administered. Geographical locations are important to be considered as the strain of a virus (or bacteria), environmental conditions, risk of exposure vary across the globe.

Vaccine development pipeline

Typically, it takes a few years of deliberate and careful work to develop a commercial vaccine. Sometimes it not possible to develop a vaccine even after extensive research as in the case of HIV. After the discovery phase, the most important phases are the pre-clinical and clinical phases. In the pre-clinical phase, vaccine testing is performed using animals to see if their immune system responds. This immune response is mapped in terms of human immune response. The main aim of this phase is to identify vaccine candidates that can go further for human trials. In clinical development, the vaccine is first tested in human volunteers following the rigorous ethical principles and their consent. Once clinical trials are approved, the vaccine must pass three trial stages of human testing: Phase I, Phase II, Phase III. Once a vaccine passes all three trial stages, it is licensed for public usage. After that, Post-licensure surveillance is carried out to detect rare adverse effects as well as to assess long term efficacy. Logistical considerations, such as the cost of the vaccine, distribution, establishment of satellite manufacturing plants, are also taken into account.

COVID-19 vaccine development

The COVID-19 pandemic has slightly changed the traditional vaccine development approach. Scientists are taking parallel paths for trials in which studies are optimized for multiple target populations throughout the world and different socio-economic conditions. For the COVID-19 vaccine to be available in the next year or so, an incredible set of circumstances need to occur including flawless scientific execution, breakneck trials, and a never-seen-before gigantic scale manufacturing along with global mobilization of vaccine doses. The data from World Health Organization (WHO) suggested that as of 20 April 2020, the global COVID-19 vaccine R&D included 76 vaccine candidates, of which 5 are in clinical stages and 71 are in the pre-clinical stage.

Company
Stage
Vaccine Characteristics
Moderna
Phase I
LNP-encapsulated mRNA vaccine encoding SARS-CoV-2 spike protein
CanSino Biologicals
Phase I/II
Adenovirus type 5 vector that expresses SARS-CoV-2 spike protein
Inovio Pharmaceuticals
Phase I
DNA plasmid encoding S protein delivered by electroporation
Beijing Institute of
Biological Products/ Wuhan Institute of
Biological Products
Phase I
Inactivated virus
Sinovac
Phase I
Inactivated virus + alum
Source: ClinicalTrials.gov website; WHO.

The Indian landscape for COVID-19 vaccine development

India is among the largest manufacturer of generic drugs and vaccines in the world. Half a dozen Indian firms are in the race to develop vaccines against COVID-19. One of them is the Serum Institute of India and has already announced the mass-production of the vaccine candidate called ChAdOx1-nCoV-19 developed by the University of Oxford. Serum Institute is also collaborating with Codagenix, an American biotech company, to develop a “live attenuated” vaccine. Hyderabad-based Bharat Biotech announced a partnership with the University of Wisconsin Madison and US-based firm FluGen and has begun the development and testing of a unique vaccine against COVID-19 called CoroFlu. Other companies include Zydus Cadilla which is working on a plasmid DNA vaccine and a live attenuated recombinant measles virus vectored vaccine, while Biological E, Indian Immunologicals, and Mynvax are developing a vaccine each.

World history has shown that the majority of the pandemics caused by viruses like COVID-19 were contained only after the discovery of an effective vaccine. Antiviral vaccines are the most successful biomedical intervention for preventing and eradicating the viral disease.


About Author: Arti Dumbrepatil is a scientist and a science writer. She worked at the University of Michigan, Ann Arbor, MI, USA, as a postdoctoral researcher. During her tenure at the University of Michigan, she also worked as a Science Communication Fellow and as a Science Communication Writer. She is the lead author in several peer-reviewed scientific journals such as the Journal of Biological Chemistry, Proteins, and Applied and Environmental Microbiology. As a Science Writer, her writings have covered various topics from Nanorobots to Virology. Arti continues to write as a contributing author to Microbiome Digest, American Society for Biochemistry and Molecular Biology.