BY DAKSHITA NAITHANI
The immune system is a system that operates 24 hours a day, seven days a week to keep assaults at bay and diseases at bay. The whole system is made up of organs, tissues, and a variety of cell types that work together to defend the body. Immune cells must be able to tell the difference between native and non-native cells and proteins. Microbial cells have antigens that serve as identifiers. Antigens can induce an immune response in the human body. Each species has its own set of characteristics. Vaccines function by inducing an antibody memory response in the body without producing illness. As a result, you build immunity without becoming sick. It must include at least one antigen from the target species to trigger a response.
INTRODUCTION TO VACCINE TECHNOLOGY
A vaccination, often known as an immunisation, is a biological substance that protects people from disease-causing microorganisms. They make advantage of our immune system’s built-in ability to fight infection.
They’re produced from the same pathogens that cause the disease. They have, however, been destroyed or reduced to the point that they are no longer a source of it. Certain medicines just contain a part of the microorganism.
This is why they work so well as medications. They don’t treat or cure diseases like conventional medications; instead, they prevent them. They deceive the immune system that it has been invaded by a real intruder. When real germs enter our bodies, the same thing happens, but you don’t become ill. If you ever come into touch with a pathogen, your immune system will remember it and eradicate it before it can damage you.
Vaccines are made using a number of techniques. Various vaccine types need different techniques to development. Antigens can be used in a variety of ways, including:
These can be delivered by a needle injected into the human skin, or ingested orally or through the nasal route.
LIVE (CHICKEN POX AND MMR)
Attenuated vaccines can be made in a variety of ways. All methods involving the transmission of a virus to a non-human host result in a virus that can be recognised by the immune system but cannot replicate in humans. When given to a human, the resulting will not be able to proliferate sufficiently to cause disease, but it will protect the individual from infection in the future. Its protection outlasts that of a dead or inactivated vaccination in most cases.
INACTIVATED (POLIO VIRUS)
A pathogen is inactivated using heat or chemicals to create this sort of vaccination. Because destroyed viruses are unable to replicate, they cannot revert to a more virulent form capable of causing disease. They are, however, less effective than live vaccines and are more likely to require renewals in order to acquire long-term protection.
They have been genetically modified in a lab. This method may be used to duplicate a certain gene. The HPV vaccine may be tailored to protect against strains that cause cervical cancer.
SUBUNIT (INFLUENZA AND ACELLULAR PERTUSSIS) AND CONJUGATE VACCINES (HAVING ONLY PIECES OF THE PATHOGEN)
Subunit vaccines use only a fraction of a target pathogen to elicit a response. This can be accomplished by isolating and administering a specific pathogen protein as a stand-alone antigen.
Conjugate vaccines, like recombinant vaccines, are made up of two different components. The “piece” of microbe being supplied would not typically elicit a substantial reaction on its own, but the carrier protein would. The bacterium is not the sole cause of the disease, but when combined with a carrier protein, it can render a person resistant to subsequent infections.
TOXOIDS (DIPHTHERIA AND TETANUS)
Some diseases are caused by a toxin produced by bacterium rather than by the bacterium themselves. Toxoids are inactivated toxoids that are used in vaccinations. Toxoids are classed as killed vaccines, although they are sometimes given their own category to emphasise the fact that they include an inactivated toxin.
DEVELOPMENT AND PRODUCTION
Vaccine development is a lengthy process that involves both public and private parties and takes almost a decade. Millions of individuals receive them each year, and the most of them have been in use for decades. Before being included in a country’s vaccination programme, they must undergo extensive testing to ensure their safety. Each vaccine in development must first go through screenings and evaluations to determine which antigen should be utilised to elicit a reaction. This step is completed without the use of humans. Animals are used to assess the safety and disease-prevention potential of experimental vaccinations.
It takes around 2-4 years to produce and necessitates some fundamental research. Antigens, whether natural or synthetic, are identified by scientists and may help in disease prevention or therapy. Antigens might be virus-like particles, attenuated viruses or bacteria, weakened bacterial toxins, or other pathogen-derived substances.
Using tissue or cell-culture techniques and animal testing, studies assess the candidate vaccine’s safety or ability to elicit an immune response. Animal topics include fish, monkeys, and mice. These studies give an idea of what to expect in terms of cellular responses in people. This period often lasts 1-2 years.
PHASE I TRIALS
The vaccine is administered to a small number of volunteers to determine its safety, confirm that it induces a reaction, and determine the optimum dosage. This round of testing is carried out on young, healthy adult participants. The goals are to determine the type and number of reactions generated by the candidate vaccine, as well as to assess the candidate vaccine’s safety.
PHASE II TRIALS
The vaccine is then given to several hundred participants to assess its safety and ability to elicit a response. Participants in this phase share the same traits as the vaccine’s intended recipients. Several studies are often undertaken during this phase to test various age groups and vaccination formulations. In most studies, a non-vaccinated group is included as a comparison group to check if the changes in the vaccinated group were due to chance or medicine.
PHASE III TRIALS
The goal is to assess vaccine safety in a large group of patients. Certain rare side effects may not have showed themselves in the low numbers of people tested in the first phase. Thousands of volunteers are given the vaccination compared to a similar number of individuals who did not receive the injection but received a comparator product to assess the vaccine’s efficacy against the illness. It is meant to protect against and to examine its safety in a much bigger group of people. To guarantee that the performance findings are applicable to a wide variety of persons, the bulk of phase three trials are conducted across various countries and different sites within a country.
PHASE IV TRIALS
Firms may conduct optional studies following the launch of a vaccine. The producer may do additional testing to determine the vaccine’s safety, efficacy, and other potential applications.
Reverse vaccinology is the use of genetic information combined with technology to make vaccines without the use of microorganisms. It assists in the study of an organism’s genome for the purpose of identifying novel antigens and epitopes that may be utilised as prospective candidates. This method has been around for at least a decade. By unravelling the entire genomic sequence, it is possible to determine what molecules make up the genomic sequence. Without needing to grow the pathogen for a longer amount of time, candidate antigens can be discovered.
Reverse vaccinology has been used to create vaccines for meningococcal and staphylococcal diseases all over the world. Infections are caused by Staphylococcus bacteria, which can be found on the skin or in the nose of even healthy persons. The bacteria Neisseria meningitidis causes a serious infection of the thin covering of the brain and spinal cord.
PRODUCTION QUALITY CONTROL AND COMMERCIALIZATION
Vaccines are biological compounds that are frequently hybridised and complex to understand. They are made through a succession of manufacturing and formulation steps, with the finished product often containing a large number of component items. As a result, unlike a tiny molecule medicine, the finished product is impossible to classify. This needs a highly controlled production system as well as a personnel capable of performing such processes on a continual basis. Control testing takes over two years and occupies more than half of the time in the subsequent manufacturing process.
STEP 1- PRODUCTION
Following clinical trials, when a vaccine reaches the pre-approval stage, it is evaluated by the applicable regulatory authority for quality, safety requirements.
STEP -2 MAKING
Businesses will create development plans for a vaccine on their own. Once a vaccine is approved, production begins to pace up. The antigen has been rendered inactive. All of the components are mixed to make the final product. The entire process, from testing to manufacturing, can take a lengthy time to complete.
STEP- 3 PACKAGING
It is then bottled in glass vials and packed for safe cold storage and transportation once it is produced in bulk. It must be able to resist severe temperatures as well as the dangers associated with international shipping. As a result, glass is the most often used material for vials since it is robust and can keep its integrity under severe extrinsic factors.
STEP- 4 STORAGE
When it is excessively hot or cold, it loses its effectiveness and may even become inert. Vaccinations can be destroyed or rendered dangerous to use if kept at the improper temperature. Most vaccinations must be kept chilled between 2 and 8 degrees Celsius, necessitating the use of specialist medical freezers.
They are transported out using particular equipment so as to maintain its integrity. Lorries deliver them from the airport to the warehouse cool room after supplies arrive in the market. New innovations have resulted in the development of portable devices that can keep vaccines cold for several days without the need of power.
Once they are given out, authorities continuously check for – and assess the severity of – any potential side effects and responses from the recipients. Safety is a top priority, with frequent reviews and post-approval clinical trials reporting on its effectiveness and safety.
There are several prospects in vaccine research and development, clinical trials, vaccine manufacturing, and public distribution. These jobs are available at universities, companies, government laboratories and agencies, hospitals, and on the front lines of vaccine distribution all around the world. When different components of a project are handled by different groups at the same time in industry, greater teamwork is usually required, whereas a scientist in an academic lab may be a lone worker overseeing all parts of a project.
The balance between creative science and all of the business administration that comes with securing money, maintaining a budget, and overseeing other scientists or assistants is the most challenging aspect.
Research allows scientists to work on a project that has the potential to have a direct influence on public health, whether it’s on a lab bench, a production line, or to support a clinical trial.