It is safe to say that vaccines are one of the greatest advancements in preventative medicine. 87% of all one-year-olds received a tuberculosis immunization in 2022, and over 70% of one-year-olds received polio, hepatitis B, meningitis, measles, tetanus, diphtheria, and whooping cough immunizations. These are all diseases that used to claim thousands of lives globally and are now on the decline. 

What are Vaccines? 

A vaccine is more or less anything that has been designed to stimulate the immune system and provide protection against a specific infectious disease. It typically contains harmless parts of a pathogen, such as proteins or genetic material, that trigger an immune response without causing illness. 

However, increasingly complex mechanisms are being developed. One such is known as an mRNA vaccine, which essentially instructs your body’s own proteins to ‘build’ a virus and let antibodies fight it off. 

When administered, all vaccines train the immune system to recognize and remember the pathogen, enabling the body to mount a rapid and effective defense if exposed to the disease in the future, thereby preventing infection or reducing its severity.

Vaccines are found across the healthcare field, and their importance applies to healthcare workers roles’ from immunologists to doctors, nurses, and trainees completing courses like an online nurse practitioner program. For this reason alone a little knowledge can go a long way. 

Vaccine Development 

Say you have been studying an infectious disease and have found a way to produce immunity to said disease. The process from that idea to needles in arms is long and fraught with trials and tribulations, which are broken down into the following steps: 

Research and Discovery 

This is where you take that idea and test it out. As with any new medicine, it is important to make sure that you are actually onto something before investing time and effort into an antigen that shows little promise.

For those that do show promise, researchers will identify how their specific antigens can trigger helpful immune responses. The process involves studying the pathogen’s biology, structure, and mechanisms of infection to pinpoint specific components, like proteins, that the vaccine could target. 

This study uses some basic research techniques; complexity rapidly increases when tools like genetic sequencing and bioinformatics are necessary to analyze the pathogen and guide the selection of potential vaccine targets. For this reason, the process takes time — 1o to 15 years on average. The ultimate goal is to find an antigen that can effectively provoke the immune system to protect against future infections.

Proof of Concept 

Better known as the animal testing stage, this is how researchers measure the ability of a vaccine to elicit an immune response. Research, such as an animal study on monkeys aimed at developing vaccines for HIV, illustrates how animals act as the last step before human trials can commence. 

At this stage, researchers should generate better data to work with, adjust the dose, and make sure there are no side effects that previous research missed. At this point, researchers should know the exact mechanism behind the vaccine and how it affects the body. 

Testing 

The vaccine testing phase, usually known as clinical trials, evaluates a vaccine’s safety and effectiveness in humans. It consists of three stages aimed at a few key goals, with one goal superseding all others: data. Before a vaccine can be approved, researchers have to collect and analyze huge amounts of data. 

Phase I trials involve a small group (20 to 100) of healthy volunteers to assess safety and optimal dosage. Phase II trials expand to a larger group (100 to 200), including at-risk individuals, to further evaluate safety and immunogenicity while identifying potential side effects. Phase III trials involve thousands of participants to assess efficacy and long-term safety compared to a placebo. After successfully completing at least 4 phases, companies will apply for approval from the Food and Drug Administration (FDA) before potentially completing Phase IV trials on thousands of participants to ensure long-term safety and efficacy. 

Unfortunately, only about 7.9% of drug trials are successful. Luckily, some recent advancements have been rapidly improving the efficiency of drug trials; researchers at the University of Illinois Urbana-Champaign have developed a program called HINT, which uses AI to predict whether a trial will succeed based on the drug molecule, target disease, and patient eligibility criteria.

Manufacturing 

After a drug has been developed in relatively small quantities for a clinical trial, production must be scaled up. Vaccine manufacturing is a complex and tightly regulated process. Manufacturers have strict guidelines set by the FDA to maintain the safety and efficacy of the vaccine. The FDA’s Center for Biologics Evaluation and Research (CBER) oversees this process, conducting rigorous inspections and requiring detailed documentation on manufacturing procedures. Quality control measures are constantly implemented to test for contaminants and verify that each batch meets stringent standards. 

Regulatory approval 

Keep in mind that the entire process up until now has taken years — if not decades — to get this far. The manufacturer is also no stranger to the FDA as they have analyzed the manufacturing process and potential early trials. When the company that has developed the drug is happy with the rigor of its clinical trials, it can apply for what is known as a BLA or Biologics License Application. 

After applying for a BL, the FDA will go through an intense process that boils down to large-scale risk assessments. If the benefits outweigh the risks, you have yourself a vaccine that is fully approved for distribution to its intended users across the US. 

The Nuances 

What gets lost in the big picture that makes up each step of the process are the things that tie it all together. Creating a profit is essential to fund the entire process, which is where business meets with science, and commercialization is born. Most of the time, vaccines are not the most profitable enterprise and only made up about 8% of pharma revenue in 2021. For these reasons, the US government actually funded research into mRNA vaccines to the tune of 31.9b in the 3 decades leading up to 2022. 

Taking a new vaccine all the way from research to approval is really a testament to the power of scientific innovation and human perseverance. The field of medicine as a whole has advanced exponentially in recent times, and vaccinology has not been left behind with the emergence of technology like mRNA and AI. With sustained investment in research, collaboration between governments, academia, and industry, and a commitment to open access, vaccines will continue to fight infectious diseases for years to come.