As the coronavirus pandemic continues to rage around the world, some of the largest outbreaks are in countries that fall into one particular economic category. They're not rich. They're not poor. They're middle income.

In fact, of the countries reporting the most cases globally, 6 of 7 are middle-income nations.

And they're not just any middle-income countries. They're some of the most influential players in the global south. Brazil, India, Mexico, Peru, Russia and South Africa are not only major emerging market economies, they're regional political powers.

Middle-income countries are defined by the World Bank as having annual per capita income between $1,000 and $12,000. The U.S., by comparison (the one high-income country in the top 7), has an average annual income of $66,000.

In mid-July, South African President Cyril Ramaphosa called the pandemic the "gravest crisis in the history of our democracy" as he reimposed strict lockdown measures.

South Africa has now reported nearly a half-million cases of the coronavirus. Health officials project cases to continue to rise at least into September. And the impact of the pandemic goes far beyond the number of sick or dead. South Africa's borders remain closed. Nonessential workplaces remain shut. The country's official unemployment rate, which had been in the mid-20% range, was pushed above 30% by the pandemic.

Indeed, the strain on countries in the middle-income category is tremendous. And the number of people affected is huge. According to the World Bank, 75% of the world's population live in middle-income countries.

Collectively over the past decade, these countries have lifted hundreds of millions out of poverty.

Amanda Glassman, the executive vice president of the Center for Global Development, says these countries have a lot to lose in this pandemic.

"Most of their populations in this group would fall back into poverty given a shock like this one," she says.

For instance, Brazil's economy is expected to shrink by as much as 6.5% this year because of the coronavirus crisis. Brazil has the second-highest number of cases after the U.S. Nearly 100,000 people have died. The president and several of his top ministers have been infected. And as the pandemic continues to spread, more and more Brazilians are losing work.

"Even a country like Brazil that was so wealthy, 90% of the country earned less than $10 a day," Glassman says.

"I'm worried that we're setting back the process of economic and social development that has gone so quickly over the past decade," she says. "And it will take us many years to catch back up."

The entrepreneurial spirit that made countries like India, Brazil and South Africa dynamic emerging markets also put them at greater risk of having large outbreaks. These are places with a lot of "hustle," as Glassman puts it. Their economies were global. Business travelers and tourists jetted in and out. They have decent domestic transportation networks offering the coronavirus or other pathogens easy avenues to spread. They have health systems capable of detecting the disease.

"In India, for example, they're doing a lot of testing," says Jonathon Keymer, an intelligence analyst at the global risk management firm WorldAware. "In Russia, they're doing a lot of testing. The more people you test, the more confirmed cases you're going to have."

Keymer specializes in Russia and the former Soviet bloc countries for WorldAware and has also been modeling the impact of COVID-19 in these nations.

He says some middle-income countries globally look worse than others in this pandemic simply because they are open, dynamic societies and their case numbers are being reported. But that's not true everywhere.

He points out that both Kazakhstan and Uzbekistan, two middle-income former Soviet states, have reintroduced nationwide lockdowns in the past couple of weeks despite reported case numbers remaining relatively low.

"And then in Turkmenistan, which is a much more difficult place to get information about, they've closed the borders and I don't think they've officially got a single case of COVID," Keymer says. "But you can bet your bottom dollar that they've got COVID."

The World Health Organization has raised alarms about Turkmenistan despite its continued insistence that it has no cases.

But on paper at least Turkmenistan looks like it has far less of a COVID-19 problem than Peru, which has tested aggressively and openly reported results. Peru has a testing rate of roughly 70,000 tests per 1 million people a rate more than five times the global average.

Tanzania is another middle-income country reporting remarkably few infections. The east African nation actually hasn't officially reported any cases to WHO since April, when the president declared that the virus had been driven out of his country by prayer.

Even with the marked differences in middle income countries everything from governance to public sentiment to economic structure there are certain commonalities. It is clear that middle-income countries face similar risks as wealthier nations for coronavirus outbreaks but have far fewer resources to deal with them.

Interestingly, the relative wealth of a middle-income country appears to have little to do with how many infections it has.

Deborah Barros Leal Farias, a lecturer at the University of New South Wales, says the experience of middle-income countries shows that a nation's economic status doesn't determine its success in battling this pandemic. "If you take the U.S., the U.K. and Sweden, they are also having horrible numbers," Farias says. "And then you can take a country like Vietnam or Thailand and they're having phenomenal numbers."

She says the real issue in keeping case counts down even more than resources appears to be leadership.

Of the four countries with the most cases globally the U.S. and three middle-income nations: Brazil, India and Russia all have conservative or right-wing leaders who espouse populist or anti-science views.

In Brazil, President Jair Bolsonaro downplayed the seriousness of the disease as tens of thousands of Brazilians died from COVID. Even when he tested positive for it himself, Bolsonaro continued to tout the anti-malarial drug hydrochloroquine as a cure despite studies showing it wasn't effective against the virus.

Ester Sabino, a virologist at the University of Sao Paulo, says Brazil never had a cohesive national plan for how to address the outbreak and she says Bolsonaro has been a distraction.

"In April and May, the main discussion [in Brazil] was whether we should or should not use chloroquine instead of saying how do we stop this," Sabino says. "There was not a good plan. That's my opinion. A lot of time was spent on things that were not the key things for the control of the disease."

Research by Sabino and her colleagues shows there were more than 100 different introductions of the virus into Brazil in the early days of the pandemic, mostly from travelers who had been in Europe. Then the virus spread to every corner of the vast country.

Lockdowns managed to slow the initial explosive spread, but Sabino says there needs to be more focus to contain the ongoing outbreak.

"There is no magic. There is no free lunch. If you want to control epidemic, it's hard," she says. "And you have to work a lot. We can't think about politics."

And that appears to hold true regardless of whether a country is rich, poor or somewhere in the middle.

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