Humans across the globe have become very  interconnected–and so has our health.

No matter how we try to slice  and dice up our planet with   political and geographical boundaries,  health remains a species-wide concern. In some cases, our health has blurred  these boundaries.

And in other ways,   human health has been decided by them. But with over 7 billion people living in about  200 different countries across the planet,   global health can be … complicated.  Challenging. Even surprising.

Like, it turns out that the communicable  diseases we often think of as the biggest   killers–like malaria or the flu–actually aren’t  the leading causes of death in most places. So then…what is? And, how do entire countries  provide care for each other?

And what if a country   doesn’t want help from other countries? And what  if the “help” actually harms other countries? Hi, I’m Vanessa Hill, and this  is Crash Course Public Health!

INTRO So one sort of obvious problem with the term   “global health” is that it can  feel very big and unspecific. And this is partly because it needs to be!  After all, we’re talking about a whole planet! In general, we can think of global health  as a public health approach that puts   emphasis on improving health for everyone  in the world, while eliminating the health   equity gaps that result from things  like nationality, income, and gender.

How successful is it at accomplishing  those goals? Well…it depends. We’ll get to that.

But first, a little historical context. The question of when human health became a  global phenomenon is really up for debate. Like, did it begin during the industrial  revolution of the 18th century when the world saw huge spikes in international trade and  development?

Or was it back in the 13th century,   when Genghis Khan conquered around 9 million  square miles of territory? Or, like, was it at   the dawn of the human species, when our early  ancestors began their migration out of Africa? These are all good answers to the question.  But let’s fast forward to April 1948,   with the establishment of the World  Health Organization, or the W-H-O.

By this point, human civilization  was indisputably a very global phenomenon–  as made evident by the fact that  we’d just come out of our second World War. So, the United Nations formed the WHO,   a special agency dedicated to monitoring  and improving the world’s health. The WHO’s Constitution declared that  the organization’s objective “shall be the attainment by all peoples of the  highest possible level of health. ” This was one of the first global movements that   basically established health as  an international human right.

Which feels like it should’ve been obvious from  the start, but I guess we needed it in writing? The WHO is basically in charge of making a  vision board for the entire planet’s health. It sets international standards for health,   collects and analyzes data from around  the world, monitors concerning new and   old diseases, and helps coordinate emergency  responses and research between countries.

When the WHO was formed, the leading cause of  global human death was communicable diseases. These are diseases that are  spread–or “communicated,” as it were– from one living thing  to another through pathogens. These are things like bacteria and viruses   that are spread through respiratory  droplets, blood, saliva, and such.

A pathogen knows but two laws: reproduce  in an organism and spread to new ones. It doesn’t notice or care when it  crosses the border from Egypt to Libya,   or when it hitches a ride on a  red-eye flight from Boston to Berlin. And as people became better at moving  around resources and–well–themselves,   they also got better at  moving these pathogens around.

Whether it was trade facilitated along the Silk  Road, or that spring break trip to Disney World,   people have gotten really good at building germy  superhighways of trade, travel, and tourism. Without a globally coordinated response,  eliminating a disease across the face   of the planet is a bit like playing a game of  whack-a-mole, with a disease being squashed in   one part of the world, only for it to pop up in  another part…and another part…and another part. One particularly dangerous  communicable disease was smallpox.   Scientists have found smallpox-like  rashes on Egyptian mummies,   suggesting that humans have been dealing with  some form of smallpox for over 3,000 years.

And in the 20th century, smallpox  was still a major threat. Historically, experts estimate  that smallpox killed more than   300 million people since 1900 alone. So in 1959, the WHO added a bold new mission  to its vision board: eradicate smallpox.

The virus was killing millions of  people each year, with outbreaks   happening all over the world and  even spreading between continents. Eradicating smallpox would mean  ensuring that not a single person   on Earth had the disease so it  could never be spread again. So, we got to work.

And after a couple of attempts, thanks  to effective interventions in dozens   of countries and mass educational  and vaccination campaigns, the WHO,   with the help of many public health workers,  succeeded. In 1977, the last confirmed case of   naturally-acquired smallpox was identified  in Somalia–and then, smallpox was gone! The WHO has led similar global responses  against other communicable diseases,   such as in the fight against  HIV and AIDS, polio, Ebola,   and COVID-19, though none have been as  successful as the smallpox campaign.

But global health isn’t just about germs  sneaking across international borders. Today, most deaths are actually  caused by non-communicable diseases,   also called non-infectious diseases,   which are diseases that aren’t spread  through things like bacteria or viruses. Instead, these diseases are caused by genetic,  environmental, and behavioral factors.

This is because, in general, as we’ve gotten  better at decreasing the rate of communicable diseases, non-communicable diseases have come  to make up a greater proportion of deaths. These are diseases like cancer, heart disease,  and diabetes. And health experts address them by   managing them with medications and reducing risk  factors that contribute to their development,   like tobacco use, physical inactivity,  air pollution, and unhealthy diets.

In 2019, the WHO reported that 7 of the 10 global   leading causes of death were  non-communicable diseases. And together they accounted for 74  percent of deaths around the world. However, the biggest indicator  for whether the leading cause   of death in a country is communicable or  non-communicable, is that country’s income.

We see this pattern reflected in countries’  burden of disease, which is a measurement that   reflects the estimated years of life lost from  early deaths, injury, and illness from disease. In high-income nations, non-communicable diseases   generally account for around 80  percent of the disease burden. Meanwhile, communicable diseases tend  to make up somewhere around 5 percent   of this burden. (That last 15% is made  up of things like injury and accidents.) However, the opposite is generally  true of low-income nations,   where communicable disease accounts for more  than 60 percent of the overall disease burden.

And of course, these numbers were  reported in 2019, before COVID-19. And the solution to this problem feels simple,   right? Low-income countries  need more, you know, income.

Similarly, if they need resources like  food or doctors, other richer countries   could step in and provide aid by  selling food to those countries   at a low-cost or sending doctors to  provide more affordable healthcare. Aid dependency is the proportion of a country’s   government spending that is  provided by foreign donors. Aid is often a simple, short-term solution to  what turns out to be a much deeper problem.

When we think about foreign aid,  it’s important to remember that   high- and low-income nations didn’t  just pop into the world fully formed. They are almost always influenced by other  global, economic, and political forces. Like, consider Haiti, which in the  18th century was one of the richest   and most productive colonies  in the world under French rule.

But after a successful rebellion against the  French that resulted in its independence in 1804,   Haiti spent the next 120 years  paying reparations to France,   which took up as much as 80% of Haiti’s revenue. And in the 20th century, Haiti was subject  to an almost 20-year U. S. occupation,   where things like forced changes to their  agricultural practices led to further instability.

Today, Haiti is one of the poorest  countries in the Western hemisphere   with one of the highest rates  of food insecurity in the world. In Haiti, nearly half the population requires   food assistance and 1.2 million  people suffer from severe hunger. But the solution to this food  crisis isn’t as simple as we may think.

Let’s go to the Thought Bubble. So because of this aforementioned history of  foreign exploitation, Haiti hasn’t been able   to sustain the agricultural and financial  resources necessary to feed its population. So, Haiti relies on aid from other,  richer countries, like the U.

S. Today, over 80 percent of rice and nearly half of  all the food consumed in Haiti is imported. In an attempt to make this food affordable,   the countries exporting it often  sell it below standard market price.

However, as a result, local Haitian  farmers often can’t compete with the   price of this cheaper imported food, which  can eventually put them out of business. Suddenly, Haiti has even less home-grown  food, and so is even more dependent on aid. Meanwhile, the deeper challenges underlying  Haiti’s widespread food insecurity persist,   like lack of jobs, poor education,  and ineffective trade policies.

In fact, they might have even gotten worse,  since the need for a self-sufficient food   system has declined, disguising the  extent of those deeper problems. This is why in 2010 the Haitian government  called for an end to international food aid. Instead of providing food aid,  international institutions can   help to develop the infrastructure  and workforce necessary for Haitians   to achieve sustainable long-term economic growth.

For example, the World Food Programme  has done this by buying local foods from   Haitian farmers at market price to revitalize the  agricultural sector and tackle food insecurity. Thanks, Thought Bubble. So  Haiti has a food problem.

But at a deeper level, it has a system problem,   because it’s struggling to escape the  systemic injustices of its history. Acts of global aid response must simultaneously  balance short-term needs, like hunger,   with longer-term considerations,  like becoming truly food independent. When we think about global health,   there can be a tendency to think about it  as something that happens somewhere else.

But this is flawed thinking for a few reasons.  Like, as we saw in the COVID-19 pandemic,   an “over there” problem can very  easily become a “right here” problem. But there’s also another, deeper sense in  which this mindset doesn’t quite hold up. Across the world, there are health issues  that we have proven to be pretty bad at   addressing no matter where we  are or how much money we have.

This is the case with mental health. Using  WHO data from 2005, researchers estimated   that mental health accounts for as much as  14 percent of the global burden of disease. And yet, across the world, mental health care receives much less attention than other forms of health care.

In fact, an analysis of funding across 10  years found that health care development funds   dedicated to mental health accounted for just  0.3 percent of all global healthcare spending. Another area in which we have  collectively and consistently   dropped the global health ball is maternal health. The WHO estimated that in 2017, over 800 women  died every day from preventable causes related   to pregnancy, mainly due to a lack of quality care  during pregnancy, and during and after childbirth.

And while as of 2019 ninety-four percent of these   deaths occurred in low income  and low resource countries,   rich countries like the United States continue  to see large variations in maternal health. When it comes to addressing health at a worldwide  level, we must look to global cooperation. One way we have of doing this  is with disease surveillance,   or the systematic process of gathering, analyzing,   and interpreting health data, and then  making that data accessible to everyone.

It also means having compassionate, honest,  and culturally sensitive conversations. And it means following up on those  conversations with actions to address   the root causes of poverty and injustice  that lead to health inequities in disease   distribution and access to life saving  resources like vaccines and medications. As a species, we’re still figuring  out what it means to share a planet   and share the responsibility for  taking care of one another’s health.

The field of public health is constantly  grappling with an important ethical question:   Who do we mean when we say “we”? Our  neighborhood? Our country?

The whole world? When we start thinking about our health  as a shared and global phenomenon,   we come a bit closer to finding the answer. Thanks for watching this episode  of Crash Course Public Health,   which was produced by Complexly in partnership  with the American Public Health Association.

If you want to learn even more about Public  Health, head over to APHA’s YouTube channel   to watch “That’s Public Health” a  series created by APHA and Complexly. Crash Course was filmed in the Castle  Geraghty studio in Indianapolis, IN,   and made with the help of  all these wonderful people. If you'd like to help keep Crash Course free for   everyone forever please consider joining  our community of supporters on Patreon.