While some countries are talking about herd immunity, a vaccine for COVID-19 looks like the only possible way to contain the spread. Here is a look at the status & progress of vaccine development across the world. Globally, the highest ever daily increase in the number of COVID-19 positive cases was recorded on 04 June 2020, when close to 1.3 Lakh new cases were reported. The total number of positive cases globally has crossed 65 lakhs, according to WHO’s dashboard. The number of deaths has crossed 3.9 lakh. Vast majority of the global population is still vulnerable to COVID-19. In India, the number of daily cases has increased substantially ever since the relaxation of lockdown measures. The entire world is waiting for the vaccine to become available. Here is a look at the progress in the development of a vaccine for COVID-19. Vaccination helps boost immunity against a disease Scientists and other experts around the world have been working rigorously to develop a vaccine for COVID-19. Vaccination helps a body’s immune system to identify and combat certain pathogens such as virus and bacteria, thereby keeping the person safe from the diseases they cause, some of them which can even be deadly. Through vaccines, the disease-causing germs, which are either killed or weakened such that the person does not get sick, is injected into the body. This stimulates the immune system to produce antibodies which will prevent the disease without actually getting infected. It can take decades to develop a vaccine Development of vaccine is a long process and can take years or even decades. Many factors about the infection need to be understood such as its cause – virus or bacteria, how the germs/pathogen infects cells, and how the human immune system will respond to it. The process is long drawn and a complex one which requires the involvement of both public and private organizations. For instance, the first vaccine for the deadly Ebola virus which was discovered around forty-three years ago, was approved by the US Food and Drug Administration, only in December 2019. Now that the COVID-19 pandemic is a global emergency, resources and funding might also be diverted for vaccine development, which will facilitate quicker completion of the vaccine development process. Vaccine development happens in various stages There are broadly three stages that vaccine development must undergo, according to WHO. These are developmental, licensure, and post-licensure. The developmental stage can be further sub- classified into preclinical, clinical research and development. Preclinical research and development are carried out in the laboratory assays and on animals, if necessary. At this stage, information such as details of development and production of vaccine along with reports of control testing are collected, to justify further clinical study in humans. Clinical trials in humans take place in three phases Clinical trials in humans are classified into three phases- phase I, phase II, phase III. For this, prior approval is required in some countries like UK and USA. In phase I, the vaccine is tested among a small number (~20) of healthy adults mainly concerning safety. The vaccine’s properties, and tolerability are tested, and if found appropriate, its clinical laboratory and pharmacological parameters are also recorded. Gradually, in phase II, the study is expanded. A target population is selected based on characteristics such as age and physical health similar to those for whom the vaccine is intended, to obtain preliminary information on the vaccine’s ability to produce desired effect among them and general safety. Phase III involves mass testing of thousands. The vaccine is given to a larger number of people to assess protective efficacy and safety yet again. But this time, adequate data needs to be collected so as to clearly show that it is safe and effective for the intended purpose. By the time this stage is reached, vaccine characterization should be complete, that is, virus’ properties should be analysed and how it is related to other viruses should be assessed. Also, final manufacturing process, specifications, and batch release testing procedures must also be ready. Once clinical trials are done, market authorization can be applied for the vaccine The data from phase III is used to apply for market authorization at the national regulatory authority in the country. If there are genetically modified organisms, an Environmental Risk Assessment and approval are required. Licensure is when approval is granted to conduct vaccine trial on the general public. Once this process is complete, the vaccine is introduced and used in general population.