﻿Hi, I'm John Green and this is a slightly different episode of Crash Course. We’ve
heard from so many teachers and students who are using Crash Course videos to help with learning
amid all this uncertainty, and we are really grateful. We’ve also heard from many of
you just how difficult it is to learn and teach right now. This has made everything difficult.
These days, “it” and “this” are often pronouns that require no antecedent, but I’ll define
them anyway: Covid-19, a disease caused by the SARS-CoV-2 virus, has spread across the entire
human community. In the first seven months of this pandemic, more than a million people died of
Covid. Many people are out of work, and millions are learning from home or learning in school
environments that may feel--and may be--unsafe. And because the virus spreads through humans doing
things that used to be considered normal--sharing a snack, sitting in
enclosed spaces with other people, talking with friends--the way we interact with each
other has shifted dramatically and suddenly . When I think about disease and its treatment,
I usually first think about, like, medicines and vaccines. If I think a little harder,
I might consider medical devices--ventilators, dialysis systems, and so on. But disease is not
only treated by those interventions. Similarly, I tend to think of infectious disease as being
inevitable, which in some ways it is--but only in some ways.
Like, take cholera, for example. It is accurate to say that cholera is a disease caused by the bacterium
Vibrio cholerae, which infects humans who drink contaminated water or eat contaminated food.
And it is accurate to say that the disease is preventable via vaccine and treatable
with rehydration solutions and antibiotics. But it is also accurate to say that cholera
is caused by humans--we spread the disease to each other, and it spreads because many
humans don’t have access to clean water or safe sanitation systems. In Yemen, for instance,
a massive outbreak of cholera began in 2016 during a Civil War as the sewage system fell apart.
Did Vibrio cholerae cause that disease outbreak? I mean, in some ways, yes, but in other ways,
it was made possible by human violence and the breakdown of human-built systems.
It’s no coincidence, then, that cholera almost exclusively sickens and kills poor
and marginalized people. Infectious disease affects people unequally because our governments
and social orders treat people unequally. Disease amplifies injustice. It always has.
We see that historically, when cholera disproportionately killed
enslaved Americans in the 19th century. And we see it today: Here in the United States,
the Covid-19 pandemic is disproportionately affecting Black Americans, Native Americans,
and other marginalized groups. And we see similar disparities from Australia to Germany to Brazil.
And so when we think about disease and its treatment, we need to think not just about
drugs and vaccines and medical devices, but also about humans: Human history, and human choices,
and human-built systems. Medicine can treat cholera. But so can sewage systems.
I think it’s important to use this lens when thinking about the covid-19 pandemic,
because Covid-19 is caused by SARS-CoV-2, but it is perpetuated by human behavior,
human choices, and the functioning or failure of human built-systems -- from
healthcare to transportation to governance. Medicines to treat the illness and vaccines
to prevent it are tremendously important, but so are other interventions we may not be used
to thinking of as medicine--like for instance wearing a mask in public, and washing our hands,
and keeping physical distance between people. Just as Covid spreads through our behavioral choices,
it can be prevented by them. And so even if you're not in a position of systemic power, there is a lot of
power to the choices you make as an individual. And when we expand our understanding of healthcare
to include human choices, we can see what a big deal public health really is. When we as
a society start building better sanitation systems, cholera disappears. When we as a society use less tobacco,
cancer rates drop. And when we as a society keep distance when possible and wear a mask in public,
Covid-19 infections decline, and fewer people are hospitalized, and fewer die.
So, our company Complexly has other great channels like Healthcare Triage with Dr. Aaron Carroll and SciShow that are
providing in-depth updates on COVID-19. But this is Crash Course, so we will stick to our
brand with some widely applicable, evidence-based public health advice that we put together
with the help of our friends at Operation Outbreak and the Sabeti Lab at Harvard University.
One of the greatest challenges of Covid-19 is that people who’ve been infected with
the virus but don’t show symptoms, or have not yet shown symptoms, can still spread
the virus. Communities are blind-sided by this asymptomatic spread since people
don’t know they are transmitting the virus. Recent research tells us that asymptomatic spread
drives much of the disease is common and can cause super-spreading events, potentially infecting
many people at once. This happened at a biotech conference in February,
where scientists and researchers from all over the world congregated in Boston.
And while they didn’t know it at the time, at least one of the attendees was carrying COVID-19,
which they spread around the conference. And later on, scientists were able to use genome sequencing on
the virus to link that one conference outbreak to infections in tens of thousands of people.
So you don't have to be sick to spread Covid. That's why we wear face coverings that cover our nose and our mouths, regardless of whether we don't feel good.
Because we don't know.
Since the Sars-COV-2 virus is primarily spread through respiratory droplets splattering
one person to another, anything we can do to prevent that reduces the risk of transmission.
This means wearing a mask to physically block droplets from your mouth and nose,
physically distancing to reduce the amount of people who are exposed to your droplets,
and washing your hands with soap to get rid of any infectious stuff that you may have touched.
By the way, if it sounds like I'm repeating myself when it comes to physical distancing, wearing a face covering that covers your nose and your mouth,
and washing your hands...that's because I am repeating myself.
You might have heard of these things in the context of "flattening the curve,"
which is a way to say that slowing the spread of infection will help us to avoid
overloading our medical clinics and hospitals with sick people.
An overload of Covid patients decreases the overall quality of healthcare and can mean
in some cases that people don’t get care at all, which affects people infected with Covid-19 /but also/
anyone else who has any other health problem.
And we already know from experiences around the world that more rapid spread of Covid-19 generally means that our communities suffer greater losses.
Now, due to the great variety of life circumstances among humans, there’s no, like, one-size-fits-all Covid-19 protection
advice. Some folks have a job that requires them to be in the same room as other people,
or they don't have access to clean protective equipment, or they have
to take care of an older family member. And for many people involved in teaching an learning right now, all three of these things
can be true at once and many more.
Every person's circumstances are different, but what we know consistently is that we can decrease the risk of the spread of Covid in our communities
through physical distancing, wearing a face covering, and washing your hands.
If it sounds like I'm repeating those things...it's because I am.
There’s another important public health strategy for limiting the spread of Covid-19: contact
tracing. By keeping track of who we’ve come into contact with, we can track a spreading infection
through communities, and intervene to stop it. This can be an extremely effective strategy.
It was critical in the control of the 2003 SARS outbreak and the 2014 outbreak of ebola and it will
be extremely important in controlling Covid especially because the virus can spread without symptoms.
For contact tracing to work effectively, we need quick test results--something that has
been a big problem in many communities. In lieu of that, we may need to have difficult conversations
with each other. For instance, you may need to text a friend and say, “Hey, I’ve been coughing,
sniffling, feverish, having trouble breathing, unable to taste or smell, and/or nauseated. I
haven’t yet gotten my test results, but since I hung out with you in the last two weeks and I’m afraid I
may have Covid, you should probably get tested and consider self-isolating.” But like, you know, put some
emojis in there , or whatever. I don't know how people text.
I'm 43 years old. When I send a text message, I usually sign my name at the end of it, just so they know who it's from.
But right, I know it may be uncomfortable, but it’s important. One sick person notifying their friends can save
many lives by shutting down a potential path of virus spread. Remember that conference where tens of thousands of infections
were traced to one place.
Of course, telling a close friend that they have potentially been exposed to a global pandemic is terrifying! Asking your
close friend if they might be have potentially exposed you to a global pandemic is maybe even more terrifying!
But having these conversations is very, very important. It's the "public" part of public health,
and right now we need to make choices these days with bravery and empathy.
Also, all these things we're learning now can help us improve global health
in this pandemic but also in the future. We are developing radically new diagnostic testing
and disease tracking technologies, and the World Health Organization is tracking over
170 vaccines in development right now, some of which are in Stage-3 human trials.
A vaccine would prepare our immune systems to fight off the virus so
they aren't completely taken by surprise and devastated by illness. But it will likely
not be a magic bullet to end the pandemic, but instead another tool we use to control the virus.
Eventually, we'll be able to talk about COVID-19 as a "thing that happened and
is under control" instead of "a thing that is happening." When you're living amid history,
it is very difficult to make conclusions about it. We don’t know how we will look back on this time,
but we do know that 1. This will end, and 2. Our choices matter, and can help it to end sooner.
Here at Crash Course, we hear every day how hard it is for students, teachers, and parents to
navigate education right now. We hear that it’s hard on physical health, and on mental health.
Experiences that used to be a given--that you will walk in familiar hallways, that you will hug your friends,
play sports with your teammates, sit in lecture halls, or eat lunch in the cafeteria
while surreptitiously watching a Crash Course video to cram for a test--those may be gone for now.
Maybe you’re also living with other, even more profound losses.
And all those losses are real, and I’m sorry.
So in addition to understanding that, like, our choice to wash our hands is a form of protecting health
I hope you'll check in with friends and family. Reach out for help when you need it. And remember, the active
choices you're making to limit the transmission of the virus are a gift to yourself, and also to others.
But even amid these immense challenges, we must find ways to keep learning. Let us find ways to go on learning about science and history--trying to
better understand the universe and our place in it. Let us go on learning about disease
and how to treat it--not just with medicine, but also by fighting for a more just and equitable world
where disease no longer disproportionately burdens the most vulnerable. Let us go on learning about
mathematics, so that we can understand the implications of exponential growth
before we have to live with those implications. Our species has been around for over 200,000
years, and just a thousand years ago--less than one half of one percent of our history--we
didn’t know what caused disease pandemics. We didn’t know that lead was dangerous. Few
if any people knew that the Earth revolved around the Sun. But because we are able to accumulate and
pass down so much knowledge through generations, we now know all of that, and so much more.
The people of the past worked together to learn, and then handed down to us what they knew,
as now we will work together to learn more, in the hopes that we can help the humans of the
future. Learning together across vast expanses of time and space is the human superpower.
To help you use that superpower, Crash Course is hoping to develop a series on public health,
because--you know--we need to learn more about illness and the factors that shape human health.
And more generally, we hope that our videos can be one tool among many to help keep people learning.
I don’t want to minimize the challenges of this moment.
They are immense. This sucks. But I really believe that even in these upended times,
we must find ways to go on learning the best way humans learn: Together.
So thank you for being here with us, and remember, your choices matter, you matter.