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When a new pathogen emerges,

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our bodies and healthcare systems
are left vulnerable.

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

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to create widespread immunity
with minimal loss of life.

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

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Vaccine development can generally 
be split into three phases.

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In exploratory research, scientists 
experiment with different approaches

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to find safe and replicable 
vaccine designs.

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

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

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across a variety of populations.

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Finally, there’s manufacturing,

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where vaccines are produced 
and distributed for public use.

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

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But during a pandemic, 
researchers employ numerous strategies

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to move through each stage 
as quickly as possible.

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Exploratory research is perhaps 
the most flexible.

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The goal of this stage 
is to find a safe way

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to introduce our immune system 
to the virus or bacteria.

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This gives our body the information
it needs to create antibodies

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capable of fighting a real infection.

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There are many ways to safely trigger
this immune response,

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

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Traditional attenuated vaccines 
create long lasting resilience.

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But they rely on weakened viral strains

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

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Inactivated vaccines take 
a much faster approach,

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

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

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can also be created quickly.

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But these faster techniques produce
less robust resilience.

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These are just three 
of many vaccine designs,

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each with their own pros and cons.

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No single approach is guaranteed to work,

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and all of them require 
time-consuming research.

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

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to work on different models 
simultaneously.

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This race-to-the-finish strategy

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produced the first testable 
Zika vaccine in 7 months,

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

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Being testable doesn’t mean 
these vaccines will be successful.

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But models that are deemed safe 
and easily replicable

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

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

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

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

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

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

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

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across a wider population.

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And Phase III trials determine safety

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across the vaccine’s primary 
use population,

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while also identifying rare side effects
and negative reactions.

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

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it’s incredibly difficult to speed up 
clinical testing.

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In extreme circumstances, 
researchers run multiple trials

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within one phase at the same time.

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

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Occasionally, labs can expedite 
this process by leveraging

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previously approved treatments.

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

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producing a widely available vaccine
in just six months.

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However, this technique only works
when dealing with familiar pathogens

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that have well-established 
vaccine designs.

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After a successful Phase III trial, 
a national regulatory authority

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reviews the results and approves 
safe vaccines for manufacturing.

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Every vaccine has a unique blend 
of biological and chemical components

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that require a specialized pipeline 
to produce.

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To start production as soon 
as the vaccine is approved,

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

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This requires constant coordination
between labs and manufacturers,

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

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even if that means scrapping
months of work.

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Over time, advances in exploratory
research and manufacturing

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should make this process faster.

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Preliminary studies suggest 
that future researchers

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may be able to swap genetic material
from different viruses

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into the same vaccine design.

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These DNA and mRNA based vaccines
could dramatically expedite

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all three stages of vaccine production.

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But until such breakthroughs arrive,

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our best strategy is for labs 
around the world to cooperate

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and work in parallel 
on different approaches.

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By sharing knowledge and resources,

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scientists can divide and conquer 
any pathogen.