How exactly does a vaccine get made?

The history of vaccines is a story of human ingenuity, science, tech and perseverance against the odds.

The work our global vaccine creators are doing to help stem the tide of disease, and create better living conditions for millions has been rightly celebrated over the last 100 years. From the eradication of Smallpox mid-century, to the incredible scientific leaps in the last few years creating a nearly-viable vaccine against Malaria, not to mention the global COVID initiative, the intrepid scientists and producers who build and distribute the drugs that keep people alive have always been lauded as heroes amongst us.

For obvious reasons, the last 2 years have seen vaccine developers ushered once again into the spotlight as the global scientific fraternity came together in a flood of funding and support to rapidly build, produce, and distribute a COVID vaccine. The unprecedented global outpouring of scientific endeavor was truly game-changing, and shows what collaboration, adequate funding and unified health messaging can do.

But how exactly do vaccines get made, and what should lay-people understand about the unique business of making a vaccine?

What is a vaccine?

Vaccines are engineered pathogen antigens, which, when placed into the body, encourage the recipient to create antibodies – as the WHO describes it, antibodies are the “soldiers” that fight off, reduce the effect of, or completely eradicate, a pathogen from the body. A pathogen can be a bacterium, virus, parasite or fungus.

While pathogens have many constituent parts, the antigen is where vaccine creators spend their time, as antigens are what the body “maps” to create antibodies. We have thousands of antibodies in our system, but it takes time to develop new antibodies when exposed to a new pathogen. In that middle period between exposure and antibody creation is where we get sick.

How do vaccines help?

In short, vaccines are smaller, less dangerous versions of a pathogen, which urge the body to create antibodies to better fight the real thing. These versions can be engineered, less severe versions of the pathogen, or simply a “blueprint” of the pathogen. The critical thing is that they are carefully created to lessen the impact of the pathogen, but encourage the production of antibodies.

“This means that if the person is exposed to the dangerous pathogen in the future, their immune system will be able to respond immediately, protecting against disease”.

What are vaccines made of?

As per the WHO, vaccines contain:

• Antigen: the active part of a pathogen that creates an immune response,
• Preservatives: solutions to prevent contamination upon opening,
• Stabilizers: to prevent chemical reactions from occurring within the vaccine such as sugars or amino acids,
• Surfactants: to keep all the ingredients in the vaccine blended together, and prevent clumping,
• Residuals: tiny amounts of various substances used during manufacturing or production of vaccines that are not active ingredients in the completed vaccine, such as yeast,
• Diluent: water, to dilute the vaccine to the correct concentration,
• Adjuvant: An adjuvant improves the immune response to the vaccine.

What is phase testing?

“Each vaccine under development must first undergo screenings and evaluations to determine which antigen should be used to invoke an immune response”.

• Phase 1: the vaccine is given to a small group of volunteers to test safety, generally in young adults with healthy immune systems,
• Phase 2: the vaccine is given to several hundred volunteers with a range of similar characteristics such as age, height, weight etc, generally held in multiple stages to test different groups,
• Phase 3: Normally held across multiple countries with many thousands of recipients.

What is an mRNA vaccine?

These are slightly different to traditional vaccines, in that the vaccine triggers the creation of a protein, that then in turn triggers an immune response that then creates antibodies. The Pfizer and Moderna COVID vaccines are mRNA vaccines, which you can read about more here.

How are vaccines manufactured?

1. Vaccines are “grown” in bioreactors, within yeast or bacteria, where the antigen can then be isolated,
2. The antigen is then released and isolated,
3. The antigen is then purified,
4. The adding of adjuvants or stabilizers,
5. The vaccine is then made at scale and distributed.

Summary

Vaccines are incredible feats of bioengineering. The work scientists have done in the last 2 years to help us survive the worst of COVID-19 should be seen as nothing more than a defiant, intelligent application of vaccine tech and knowledge to one of the world’s greatest crises.