Here’s Why Development of a Vaccine Takes So Long

From The Daily Signal.com (April 27):

As the world battles the COVID-19 pandemic, the White House has warned time and time again that a vaccine for the SARS-CoV-2 virus won’t be available for another 12 to 18 months.

In a crisis, that sounds like forever.

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Vaccine development is a complex, multistep process that includes rigorous clinical testing and regulatory hurdles.

Throughout the vaccine development process, scientists, policymakers, and government regulators must constantly walk the tightrope between speed, efficacy, and product safety to produce a vaccine that creates a neutralizing immune response to the virus.

With that in mind, let’s take a look at the process.

Step 1: Research

Identify the pathogen: Before a vaccine candidate can be developed, the biological pathogen must be identified, isolated, and analyzed in a laboratory. This process includes genetic sequencing to get an understanding of the virus’ structure.

Develop a candidate: Traditionally, vaccines are developed by “growing” pathogens that are either inactive or reduced in potency. Once injected into a host, these trigger an immune response to protect against the real virus.

Preclinical testing: Before a vaccine can be tested in humans, it’s investigated carefully in a lab. This step usually involves animal trials, but regulators have allowed researchers to skip this step to fast-track development of a SARS-CoV-2 vaccine.

Step 2: Human Clinical Trials

Once a vaccine candidate is identified and clears preclinical testing, scientists prepare it for human studies. What works in the lab doesn’t always work in human hosts.

Clinical trials are usually conducted in three phases.

Phase 1: Potential vaccines are given in small doses to healthy human volunteers. These studies are designed to make sure the vaccine is safe while determining proper dosage. Phase 1 studies rarely have more than 100 people, and many begin with fewer than two dozen volunteers. [read more]

Other phases of human clinical trials are: Phase 2: If a vaccine candidate clears phase 1 successfully, it can be tested on larger numbers of people. Phase 3: Next, a vaccine is tested on a much larger scale. Phase 3 trials can involve tens of thousands of people and screen for rare side effects. Phase 4: After a vaccine is on the market and in clinics, prescribers monitor its use for potential adverse reactions that are reported to the manufacturer to ensure its continued safety.