We have always taken vaccines for granted. And we have rarely stopped to reflect on how important they are for public health. Today, a vaccine is the only solution to the greatest of our problems. This makes us realize that they are an essential element within our society and lifestyle.
It should be noted that talking about vaccines is talking about a very diverse world. Although the final goal is always the same (for the immune system to generate immunity against an agent), the ways to achieve it can be very different. This causes the drug production process to have some common stages, but also some different ones, especially in the antigen production steps.
But what are the main types of vaccines, and how each type affects the process:
- Attenuated vaccines: these contain the bacteria or virus, but in a weakened state so that they are not capable of causing disease, but are capable of generating an immune response. This means that the infectious agent will have to be grown in a bioreactor, and subsequently, a weakening step will have to be included, which may be, for example, inoculation of the virus into an outside host. These types of vaccines are used to prevent diseases such as poliomyelitis (OPV) or chickenpox.
- Inactivated vaccines: in this case the vaccines also contain the bacteria or virus, but dead or inactivated. Here, as in attenuated vaccines, there will be a bioreactor stage for cultivation, but then there will be the inactivation stage. This inactivation is usually done using chemical agents or heat. This typology is used, for example, for the hepatitis A or polio vaccine (IPV).
- Subunit vaccines: these types of vaccines no longer contain entire microorganisms, but are made up of parts of them such as proteins or polysaccharides that are capable of generating immunity. These subunits can be produced using recombinant DNA technology, and then purified. An attenuation or inactivation step will no longer be necessary here. These are used to prevent hepatitis B or human papillomavirus (HPV).
- Vaccines with toxoids: some bacteria release toxins once they have infected the individual. Toxoids are toxin-like molecules, therefore they generate immunity, but are not harmful. The production process is very similar to that of a subunit vaccine, since in this case a molecule is also synthesized in a bioreactor, which must then be purified. These types of vaccines are used, for example, against diphtheria or tetanus.
These are just the main types of what we could call “traditional” vaccines. New emerging technologies allow us to think about other models that include the use of RNA, plasmid DNA or viral vectors, among others.
In fact, these are not just possibilities, but they are already a reality. Without going too far, one of the most promising vaccines in development against SARS-CoV-2 is an RNA vaccine. In this, the patient is injected with RNA that codes for one of the virus proteins. Which means that in the production process we are going to have notable changes. The synthesis of the antigen will consist of obtaining millions of copies of an RNA sequence. And then, we will have to encapsulate the RNA in lipid particles to protect it until it has to act.
As we have seen, the production of different types of vaccines can have several common stages. But choosing one typology or another will irremediably condition the production process. This is why a good design of the production plant is essential to optimize costs and facilitate general operations. You want to know more? Contact us!
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