An Overview on Vaccine Development

Vaccine development is a long, complex process, often lasting 10-15 years and involving a combination of public and private involvement. [1] Vaccines contain tiny fragments of the disease-causing organism or the blueprints for making the tiny fragments. They also contain other ingredients to keep the vaccine safe and effective. [2]

 These latter ingredients are included in most vaccines and have been used for decades in billions of doses of vaccine.

Ø Antigen

Ø Preservatives

Ø Stabilizers

Ø Surfactants

Ø Residuals

Ø Diluent

Ø Adjuvant [2]

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Stages of Vaccine Development and Testing

First Steps: Laboratory and Animal Studies

Exploratory Stage

This stage involves basic laboratory research and often lasts 2-4 years. Federally funded academic and governmental scientists identify natural or synthetic antigens that might help prevent or treat a disease. These antigens could include virus-like particles, weakened viruses or bacteria, weakened bacterial toxins, or other substances derived from pathogens. [2]

Pre-Clinical Stage

Pre-clinical studies use tissue-culture or cell-culture systems and animal testing to assess the safety of the candidate vaccine and its immunogenicity, or ability to provoke an immune response. Animal subjects may include mice and monkeys. These studies give researchers an idea of the cellular responses they might expect in humans.

Researchers may adapt the candidate vaccine during the pre-clinical state to try to make it more effective. They may also do challenge studies with the animals, meaning that they vaccinate the animals and then try to infect them with the target pathogen. The pre-clinical stages often lasts 1-2 years and usually involves researchers in private industry. [2]

IND Application

A sponsor, usually a private company, submits an application for an Investigational New Drug (IND) to the U.S. Food and Drug Administration. The sponsor describes the manufacturing and testing processes, summarizes the laboratory reports, and describes the proposed study. An institutional review board, representing an institution where the clinical trial will be conducted, must approve the clinical protocol. The FDA has 30 days to approve the application. Once the IND application has been approved, the vaccine is subject to three phases of testing. [2]

Next Steps: Clinical Studies with Human Subjects

Phase I Vaccine Trials

This first attempt to assess the candidate vaccine in humans involves a small group of adults, usually between 20-80 subjects. If the vaccine is intended for children, researchers will first test adults, and then gradually step down the age of the test subjects until they reach their target. Phase I trials may be non-blinded (also known as open-label in that the researchers and perhaps subjects know whether a vaccine or placebo is used).

The goals of Phase 1 testing are to assess the safety of the candidate vaccine and to determine the type and extent of immune response that the vaccine provokes. The participants in these studies are carefully monitored and conditions are carefully controlled. In some cases, an attenuated, or modified, version of the pathogen is used for the challenge. A promising Phase 1 trial will progress to the next stage.

Phase II Vaccine Trials

A larger group of several hundred individuals participates in Phase II testing. Some of the individuals may belong to groups at risk of acquiring the disease. These trials are randomized and well controlled, and include a placebo group.

The goals of Phase II testing are to study the candidate vaccine’s safety, immunogenicity, proposed doses, schedule of immunizations, and method of delivery.

Phase III Vaccine Trials

Successful Phase II candidate vaccines move on to larger trials, involving thousands to tens of thousands of people. These Phase III tests are randomized and double blind and involve the experimental vaccine being tested against a placebo (the placebo may be a saline solution, a vaccine for another disease, or some other substance).

One Phase III goal is to assess vaccine safety in a large group of people. Certain rare side effects might not surface in the smaller groups of subjects tested in earlier phases. Vaccine efficacy is tested as well. These factors might include

 1) Does the candidate vaccine prevent disease?

2) Does it prevent infection with the pathogen?

3) Does it lead to production of antibodies or other types of immune responses related to the pathogen? [2]

Next Steps: Approval and Licensure

After a successful Phase III trial, the vaccine developer will submit a Biologics License Application to the FDA. Then the FDA will inspect the factory where the vaccine will be made and approve the labeling of the vaccine.

After licensure, the FDA will continue to monitor the production of the vaccine, including inspecting facilities and reviewing the manufacturer’s tests of lots of vaccines for potency, safety and purity. The FDA has the right to conduct its own testing of manufacturers’ vaccines.

Phase IV Trials

Phase IV trial are optional studies that drug companies may conduct after a vaccine is released. The manufacturer may continue to test the vaccine for safety, efficacy, and other potential uses. [2]


Organizations/institutions Working on “CORONA VIRUS” vaccine

A COVID19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARSCoV2), the virus causing Coronavirus disease 2019 (COVID19). [3]

WHO, UNICEF, Gavi and partners are working together to help prepare countries to be ready to introduce a COVID-19 vaccine. [4] Internationally, the Access to COVID-19 Tools Accelerator is a G20 and World Health Organization initiative announced in April 2020. National governments have also been involved in vaccine development. As of February 2021, 66 vaccine candidates are in clinical research, including 17 in Phase I trials, 23 in Phase I–II trials, 6 in Phase II trials, and 20 in Phase III trials. Trials for four other candidates were terminated. In Phase III trials, several COVID19 vaccines demonstrate efficacy as high as 95% in preventing symptomatic COVID19 infections. [3]

A list of organizations working on “COVID-19” vaccine with their name of vaccine and country of origin is given below……. [3] 

Name of vaccine


Country of origin


Sinopharm: Beijing Institute of Biological Products, Wuhan Institute of Biological Products


Sputnik V COVID-19 vaccine

Gamaleya Research Institute of Epidemiology and Microbiology


Pfizer–BioNTech COVID-19 vaccine


United States, Germany

Moderna COVID-19 vaccine


United States

Oxford–AstraZeneca COVID-19 vaccine

University of OxfordAstraZenecaCEPI

United Kingdom





CanSino Biologics, Beijing Institute of Biotechnology of the Academy of Military Medical Sciences



Vector Institute



Bharat BiotechIndian Council of Medical Research



Janssen Pharmaceutica (Johnson & Johnson), BIDMC

Netherlands, United States



United States


Anhui Zhifei Longcom Biopharmaceutical Co. Ltd.


Zorecimeran (CVnCoV)




Cadila Healthcare





IIBR-100 (Brilife)[

The Israel Institute for Biological research


Name of vaccine


Country of origin


Instituto Finlay de Vacunas



InovioCEPIKorea National Institute of HealthInternational Vaccine Institute

South Korea, United States


Chinese Academy of Medical Sciences



AnGes Inc,  AMED



Arcturus Therapeutics






Shenzhen Genoimmune Medical Institute



Shenzhen Genoimmune Medical Institute



MRC clinical trials unit at Imperial College London

United Kingdom


ReiThera, Lazzaro Spallanzani National Institute for Infectious Diseases



Globe Biotech Ltd of Bangladesh


Nano Covax

Nanogen Pharmaceutical Biotechnology JSC



Providence Therapeutics



VIDO (University of Saskatchewan)


SARS-CoV-2 Sclamp/V451

UQSyneos HealthCEPISeqirus



As of 10 February 2021, 151.49 million doses of COVID19 vaccine have been administered worldwide based on official reports from national health agencies. Pfizer, Moderna, and AstraZeneca predicted a manufacturing capacity of 5.3 billion doses in 2021, which could be used to vaccinate about 3 billion people (as the vaccines require two doses for a protective effect against COVID19). By December, more than 10 billion vaccine doses had been preordered by countries,with about half of the doses purchased by high-income countries comprising 14% of the world's population. [3]


4. COVID-19 vaccine country readiness and delivery

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