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  • When a new pathogen emerges,

  • our bodies and healthcare systems are left vulnerable.

  • In times like these, there's an urgent need for a vaccine

  • to create widespread immunity with minimal loss of life.

  • So how quickly can we develop vaccines when we need them most?

  • Vaccine development can generally be split into three phases.

  • In exploratory research, scientists experiment with different approaches

  • to find safe and replicable vaccine designs.

  • Once these are vetted in the lab, they enter clinical testing,

  • where vaccines are evaluated for safety, efficacy, and side effects

  • across a variety of populations.

  • Finally, there's manufacturing,

  • where vaccines are produced and distributed for public use.

  • Under regular circumstances, this process takes an average of 15 to 20 years.

  • But during a pandemic, researchers employ numerous strategies

  • to move through each stage as quickly as possible.

  • Exploratory research is perhaps the most flexible.

  • The goal of this stage is to find a safe way

  • to introduce our immune system to the virus or bacteria.

  • This gives our body the information it needs to create antibodies

  • capable of fighting a real infection.

  • There are many ways to safely trigger this immune response,

  • but generally, the most effective designs are also the slowest to produce.

  • Traditional attenuated vaccines create long lasting resilience.

  • But they rely on weakened viral strains

  • that must be cultivated in non-human tissue over long periods of time.

  • Inactivated vaccines take a much faster approach,

  • directly applying heat, acid, or radiation to weaken the pathogen.

  • Sub-unit vaccines, that inject harmless fragments of viral proteins,

  • can also be created quickly.

  • But these faster techniques produce less robust resilience.

  • These are just three of many vaccine designs,

  • each with their own pros and cons.

  • No single approach is guaranteed to work,

  • and all of them require time-consuming research.

  • So the best way to speed things up is for many labs

  • to work on different models simultaneously.

  • This race-to-the-finish strategy

  • produced the first testable Zika vaccine in 7 months,

  • and the first testable COVID-19 vaccine in just 42 days.

  • Being testable doesn't mean these vaccines will be successful.

  • But models that are deemed safe and easily replicable

  • can move into clinical testing while other labs continue exploring alternatives.

  • Whether a testable vaccine is produced in four months or four years,

  • the next stage is often the longest and most unpredictable stage of development.

  • Clinical testing consists of three phases, each containing multiple trials.

  • Phase I trials focus on the intensity of the triggered immune response,

  • and try to establish that the vaccine is safe and effective.

  • Phase II trials focus on determining the right dosage and delivery schedule

  • across a wider population.

  • And Phase III trials determine safety

  • across the vaccine's primary use population,

  • while also identifying rare side effects and negative reactions.

  • Given the number of variables and the focus on long-term safety,

  • it's incredibly difficult to speed up clinical testing.

  • In extreme circumstances, researchers run multiple trials

  • within one phase at the same time.

  • But they still need to meet strict safety criteria before moving on.

  • Occasionally, labs can expedite this process by leveraging

  • previously approved treatments.

  • In 2009, researchers adapted the seasonal flu vaccine to treat H1N1—

  • producing a widely available vaccine in just six months.

  • However, this technique only works when dealing with familiar pathogens

  • that have well-established vaccine designs.

  • After a successful Phase III trial, a national regulatory authority

  • reviews the results and approves safe vaccines for manufacturing.

  • Every vaccine has a unique blend of biological and chemical components

  • that require a specialized pipeline to produce.

  • To start production as soon as the vaccine is approved,

  • manufacturing plans must be designed in parallel to research and testing.

  • This requires constant coordination between labs and manufacturers,

  • as well as the resources to adapt to sudden changes in vaccine design

  • even if that means scrapping months of work.

  • Over time, advances in exploratory research and manufacturing

  • should make this process faster.

  • Preliminary studies suggest that future researchers

  • may be able to swap genetic material from different viruses

  • into the same vaccine design.

  • These DNA and mRNA based vaccines could dramatically expedite

  • all three stages of vaccine production.

  • But until such breakthroughs arrive,

  • our best strategy is for labs around the world to cooperate

  • and work in parallel on different approaches.

  • By sharing knowledge and resources,

  • scientists can divide and conquer any pathogen.

When a new pathogen emerges,

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B2 TED-Ed testable phase clinical manufacturing pathogen

How fast can a vaccine be made? - Dan Kwartler

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    林宜悉 posted on 2020/07/03
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