The novel coronavirus, now spreading through the smaller towns of Brazil's interior, risks returning to major cities in a so-called “boomerang effect,” as a lack of specialized medical treatment forces patients into larger urban centers.
The impact of a potential second wave of new cases in urban centers could complicate attempts to reopen businesses and get the economy going again, experts said.
”The boomerang of cases that will return to the (state) capitals will be a tsunami,” said Miguel Nicolelis, a leading medical neuroscientist at Duke University who is coordinating a coronavirus task force advising the state governments of Brazil's northeast.
Brazil, home to the world's second worst coronavirus outbreak behind the United States, has over 1.2 million cases of the virus, which has killed nearly 55,000 people. On most days, it is spreading faster in Brazil than in the United States, the top country by cases.
The virus initially came to Brazil through airports and spread mostly in its largest cities, but since late May it has been spreading faster in the interior of the country.
Last week, 60% of new cases were registered in smaller cities, according to health ministry data. Deaths are also rising outside of the major cities, and now account for about half of all daily deaths in Brazil.
Brazil's response to the coronavirus has been criticized by many health experts, as President Jair Bolsonaro has played down the severity of the disease, shown indifference to its rising death toll and aggressively promoted the unproven remedy hydroxychloroquine.
As the virus spreads outside of Brazil's cities, doctors are facing constraints. Only about 10% of Brazil's municipalities have intensive care units, according to public health institute Fundação Oswaldo Cruz (Fiocruz). That means seriously ill patients need to be transported to cities.
”The virus moves into the interior, along the highways, you start having community transmission, people fall ill, get worse and return to the (state) capital to be treated, said Nicolelis, describing the the boomerang effect.
At the same time, Brazil's largest cities are reopening. Sao Paulo's mayor said on Friday that it could reopen restaurants, bars and hair salons as early as Jul 6. Thousands of shops have already reopened, sending workers back to their regular commuting patterns.
The disease is now feeding off people's movement, said Gonzalo Vecina Neto, a public health professor at the University of Sao Paulo. It goes to the interior with truck drivers, it goes to the interior with people who come to the large cities to buy things to resell in the interior. That's the path.
The patterns are causing concern about overlapping curves, as cities like Sao Paulo and Rio de Janeiro pass their peaks and fall, while smaller cities are still on the rise.
Some experts say the spread of the virus should have been better contained at first. Now, one possible mitigation option is to create testing checkpoints along highways, said Christovam Barcellos of the Institute for Communications, Scientific Information and Health Technology at Fiocruz.
Identifying the person who is going to take the virus to a place is a positive thing, it's the least that we can do,” Barcellos said.