- To end the COVID-19 pandemic and to return
to some kind of normal, we're gonna need a vaccine.
But how long will it take to develop one?
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12 to 18 months is the timeline that we keep hearing about
for a potential COVID-19 vaccine.
- When do we have a vaccine?
12 to 18 months.
- We're 12 to 18 months away from this going away.
- But here's a comparison.
The fastest vaccine we've previously developed
was for mumps and that took four years to develop.
And typically it takes 10 to 15 years to develop a vaccine.
So 12 to 18 months would be record breaking.
So let's look at how vaccines for viruses
are typically developed.
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Stage one, the exploratory stage.
The exploratory stage is also known as the research
or discovery stage for a vaccine.
Here researchers are trying to come up
with the best possible way to immunize us against a virus.
This first stage can take between two to four years.
But right now scientists are speeding through stage one,
partly because of new technologies,
and also because this SARS coronavirus
has some similarities to the first SARS virus.
Researchers are developing nucleotide-based vaccines
that use the virus's genetic code
to potentially protect us from infection.
This is a new way of developing a vaccine,
where the virus's RNA or DNA prompts our bodies
to make a part of the virus
and that's how we develop immunity to it.
In January 2020, Chinese scientists shared
the genetic sequence of the new coronavirus.
This allowed researchers around the world
to understand what the virus looked like
and how it worked, and it gave them a headstart
to developing a vaccine.
So if nucleotide-based vaccines work,
that could mean that we're done
with this first exploratory stage
and that cuts up to four years off our timeline.
But, and this is a big but, nucleotide-based vaccines
have never made it through clinical trials and FDA approval.
So the exploratory stage can take up to four years.
But thanks to existing research and new technologies
for vaccine development, some COVID-19 vaccines
may already be through this stage.
Stage two, preclinical stage. [upbeat keyboard music]
This is where scientists start testing the vaccine
in cell cultures and in animals to see
if it triggers an immune response.
If there's no immune response or the vaccine
is causing harm to cells, then it's back to square one,
the exploratory stage.
So how quickly can we move through the pre-clinical stage
for a COVID-19 vaccine?
Well, the reality is there's no way to speed up this stage.
And it'll probably take at least a year.
But one way to make this more efficient
is to start doing different stages
of vaccine development simultaneously.
This is exactly what some COVID-19 vaccine scientists
are doing right now.
They're testing the vaccine in animals
at the same time that they're testing the vaccine in humans.
Doing the testing in animals and humans
at the same time is unusual.
But the FDA does have a fast-track process
in cases of public health emergencies.
Most vaccines don't make it past the preclinical stage.
But the American biotech company Moderna
is working on a COVID-19 vaccine and was able
to get from the first exploratory stage
to human trials in 63 days.
Stage three: clinical trials. [upbeat keyboard music]
This third stage is clinical trials
or testing the vaccine in people.
Most vaccines don't ever reach clinical trials.
But if they do, then this stage can take 19 months or more
and it consists of three phases.
In the first phase, the experimental vaccine
is given to a small group of people.
This phase can take about three months.
If an experimental vaccine is safe,
then it moves on to phase two.
Phase two typically takes at least six to eight months.
During phase two, the vaccine is given
to several hundred people, including a control group
who get a placebo, not the actual vaccine.
The control group helps researchers compare
how the vaccine works and control for different variables.
In phase three, thousands of people,
usually folks in the outbreak area,
will receive the experimental vaccine.
This phase can also last at least
six to eight months if not longer.
And at this point, researchers are looking to make sure
the vaccine is effective and to monitor any side effects.
These are best-case scenarios in terms of
the timeline for each phase of human testing.
Right now, there are at least three COVID-19 vaccines
in phase-one clinical trials in the U.S.
One way to speed up phase-three clinical trials
is to do something called a human challenge trial.
That's where people are given the vaccine
but then the scientists intentionally infect them
with the virus to see more quickly
if the vaccine really works.
It might sound like an extreme way
to speed up vaccine development,
but it's been done many times before,
including with cholera, dengue, and flu.
Human challenge trials raise many ethical red flags.
In 2017, there was a proposed human challenge trial
to speed up a Zika vaccine and Zika of course
can cause severe birth defects.
And that human challenge trial was criticized
by ethicists as being too risky.
So, doing the math, the quickest way
that a COVID-19 vaccine could make its way through
human testing without doing human challenge trials
is around 15 months.
But there could be delays at any point along this timeline.
Stage four, regulatory review. [upbeat keyboard music]
At this stage, the vaccine manufacturer submits
an application to receive a license
so that they can manufacture the vaccine.
Typically, it takes the FDA 10 months to conduct
a standard review, or six months for a priority review.
But the FDA can move faster
in case of a public health emergency.
And some FDA programs allow for a rolling review.
That's where the vaccine maker is submitting
information as they go along instead of waiting
'til they've finished and then submitting the application.
The FDA is responsible for overseeing the safety
of any drug or vaccine available in the U.S.
So, its review of this information
is absolutely critical before the vaccine
can make its way to a large population.
No COVID-19 vaccines in the U.S. are near this stage.
Over in the UK, scientists at the University of Oxford
are hopeful that emergency approval of their vaccine
by UK regulators could mean it's available in September.
The best case would be a rolling review
of a potential COVID-19 vaccine taking less than
the usual timeline of six to 10 months.
Stage five: manufacturing. [upbeat keyboard music]
This is the stage where drug companies start making
and distributing their vaccines.
It takes an incredible amount of resources
and investment in infrastructure, raw materials,
and scientific expertise.
Manufacturing a vaccine can take a long time.
According to one estimate, it can take between
seven to 36 months to produce and deliver a vaccine.
It can also take a really long time for companies
to scale-up their manufacturing capabilities.
The drug company Pfizer told The New York Times
that it took them $600 million and five years
just to produce a manufacturing plant
for one of their pneumococcal vaccines.
And currently, we are not at the manufacturing stage
for a COVID-19 vaccine.
But if we were, how quickly would we move?
To be honest, this is an unknown
and depends very much on the capacity
of the drug company involved.
Stage six: quality control. [upbeat keyboard music]
So, we're not done yet.
Once the vaccine is distributed to the public,
there's the ongoing stage of quality control.
And this is done in the U.S. by the CDC,
the FDA, and the vaccine maker.
[upbeat keyboard music] So how long will it take
before a vaccine is available for the public?
Well, we can go through each stage
and add up the time taken.
But often these are time ranges
and we're seeing right now that sometimes
one stage is done at the same time as another stage.
When experts optimistically say that they
expect a COVID-19 vaccine by the end of 2020,
they're talking about an emergency use-authorized vaccine,
not a fully approved one and very limited supplies of one.
Seeing a vaccine in 12 to 18 months
would mean producing millions of doses
by January or June of 2021.
If things continue to move as quickly as they are now,
there's a possibility that there could be
a COVID-19 vaccine in two years, likely in early 2022.
The major delays in potentially seeing a vaccine
by the new year would be the time it takes
to safely move through clinical trials
and the manufacturing stage.
Clinical trials usually take a minimum of 15 months.
And that's if everything goes perfectly
with the vaccine working exactly the way it was designed
and not causing major side effects.
The manufacturing stage is another unknown.
Producing a safe and effective vaccine
for millions or billions of people could take,
at minimum, seven months.
I know we're excited and desperate for a vaccine
to be available within 12 to 18 months.
But what's even more important than rushing
is that we have a vaccine that's safe
and a vaccine that works.
And until then, we're going to have to stick with
the things that we know work,
including those containment measures
such as physical distancing.
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