How are Vaccines Made?

Vaccinations have become an absolutely critical part of healthcare across the world. Established systems like the NHS offer vaccines as standard practices, while developing countries make use of vaccines as a method of controlling disease and promoting public health. In this article we look at how vaccines are made, an important process which many parts of the world depend on for public health and safety.

The first step of vaccine production

While it may seem obvious, the first stage in the production of vaccines is to identify the pathogen causing a particular disease. The world is full of a wide variety of different agents that can cause illness, and these include viruses, bacteria, fungi, and protista. Identifying which class of organism is responsible for a disease is important in determining what kind of vaccine would need to be made to counteract it, and how this vaccine would be made.

Once the type of organism has been determined, further study of the organism is needed which informs what kind of vaccine is needed. There is a staggering number of different bacteria, viruses, and fungi in the world today, and each of these is unique in some way, and so a better understanding of the pathogen causing a particular disease is needed before a vaccine can be made against it.

Manufacturing vaccines

Once a pathogen has been identified, the first step towards manufacturing a vaccine against it is to grow a large number of said pathogen by means of a process called ‘culturing’. The pathogen is cultured in specialised equipment in dedicated facilities which follow rigorous health and safety guidelines to prevent any inadvertent exposure or spread of the disease.

Vaccines do not contain unadulterated version of pathogens, they are in fact carefully prepared to induce an immune reaction (and thereby confer immunity) without posing the risks and dangers inherent in exposure to a pathogen.  So once a large enough stock of the bacteria or virus in question has been prepared, it is treated in one of a number of different ways to produce a vaccine.

The first technique involves weakening the pathogen, and the word more often used in the scientific community is ‘attenuation’. There are a number of different ways of attenuating a virus or bacteria, for example sometimes strains (subtypes with different properties than the original) of a pathogen that are not dangerous or contagious are selected. The MMR vaccine is a good example of a safe attenuated vaccine in widespread use.

The second involves isolating a part of the pathogen in question which causes the immune response whilst getting rid of the rest of it. Your body is capable of recognising distinct molecules which indicate that a disease is present, and it is these which can be isolated and used effectively in vaccines. By introducing elements of a pathogen rather than the whole thing, risks are significantly reduced, however the immunity provided is not as strong as that offered by an attenuated vaccine. This is why this type of vaccine will often need to be administered in multiple doses over time to confer the desired level of protection. 

Some pathogens cause their harmful effects and induce your body’s defences by producing toxic materials. Some vaccines are made by exploiting these toxins, which are treated in such a way that they no longer have a harmful effect on the body. They do however manage to get your body’s immune system to react, and through that confer immunity. A good example is the tetanus virus which inactivates and makes use of the toxins produced by the tetanus bacteria.

Safety in Vaccine Production

Vaccine manufacture is treated with the utmost care and vigorous rules are followed to ensure that contamination and accidental exposure is avoided. The vaccines themselves are never cleared for widespread use until their safety and effectiveness has been validated by an independent authority. The most well-known example of such an institution is the FDA or Federal Drug Authority, in the UK the Medicines and Healthcare Products Regulatory Agency (MHRA) is a key figure in ensuring that all vaccines produced are safe and effective.

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