Why the Summer Heat Isn't Slowing COVID-19 - Rolling Stone
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Scientists Thought (and Trump Insisted) Summer Heat Would Slow COVID-19. It Hasn’t. Why?

Texas, Arizona, and Florida are seeing record temperatures along with rising coronavirus cases

Hundreds of people line up at sunrise in vehicles in Phoenix's western neighborhood of Maryvale, for free COVID-19 tests.

Hundreds of people line up at sunrise in vehicles in Phoenix's western neighborhood of Maryvale, for free COVID-19 tests.

Matt York/AP/Shutterstock

Summer was supposed to save us. President Trump touted the idea back in February: “A lot of people think that [the virus] goes away in April, with the heat.” He followed that up a few months later with an insane rant about the wonders of sunlight and how “bringing light inside the body” might kill the virus.

But it wasn’t just Trump — dozens of scientific papers speculated that, like the flu, the coronavirus would melt away in the heat, sunlight, and humidity and we could all relax for a few months until a second wave of infection hit us in late fall. As the dependably idiotic presidential son-in-law and adviser Jared Kushner put it in April, “I think you’ll see by June a lot of the country should be back to normal, and the hope is that by July the country’s really rocking again.”

Well, it’s mid-July, and guess what? The pandemic is raging out of control in America, with more than 3.3 million cases and 135,000 dead. And far from being tamed by the heat of summer, some of the hotspots for the spread of the virus – Texas, Arizona, Florida – also happen to be suffering unprecedented heat waves. Phoenix hit 116 degrees on Sunday, a new record for the year. Miami tied or broke a record high every day from Tuesday through Friday last week, and just a few weeks ago saw its hottest week ever recorded. In Texas, where I am writing this, and where public-health officials are bringing in refrigerated trucks to handle the overflow at hospital morgues, July record highs were set Monday in Amarillo (110 degrees), Lubbock (110 degrees), and San Antonio (107 degrees).

So what is going on?

“It’s a good question, and I’m not sure we have the answer,” says Peter Hotez, dean of the National School of Tropical Medicine at Baylor University in Houston and one of the top infectious disease experts in the country.

In the lab, experiments on respiratory viruses have shown that sunlight, temperature, and especially humidity have an impact on transmission. Hospitals, for example, routinely use UV light to kill viruses. And humidity can impact how long droplets of aerosol hang suspended in the air. The SARS-CoV-2 virus itself is surrounded by a fatty membane that cooks like a steak when the temperature rises too high.

But what happens in the lab and what happens in the real world are two very different things. “Clearly we are not seeing any evidence of mitigating effects of sunlight, heat, and humidity,” Hotez emailed me. For one thing, the kind of ultraviolet light used to kill viruses in hospitals (known as UVC) is not the same as the ultraviolet light that filters through the atmosphere as sunlight (that’s UVA and UVB, which are a longer wavelength and vital for pretty much all life on the planet). For another, the fact that the coronavirus is a new virus, which no one has any immunity to, means that whatever small effect heat or sunlight or humidity might have on it is impossible to detect right now. “The prevailing theory is that seasonality is not relevant to a new virus pathogen as it infects an immunologically naive population and sweeps through this population,” Hotez explains.

Some scientists have suggested that the fact that heat causes people to cluster into air-conditioned rooms might contribute to the rise of infections, but Hotez says there is no strong evidence of this. “Bottom line,” Hotez says, “we are still in a steep learning curve for this virus, and we have to assume that COVID-19 cases, hospitalizations [and] deaths will continue to accelerate across the southern U.S. and also expand into other regions of the country.”

When I asked Colin Carlson, an assistant research professor at the Center for Global Health Science & Security at Georgetown University, about the link between heat waves and the virus, he had a slightly different answer. To Carlson, it’s not just that scientists are still on a steep learning curve and don’t really know the answer to the question, it’s that they have been actively wrong about it, pushing out rushed, flawed science that political opportunists like Trump and other leaders have seized on for their own purposes.

“The conversation has gone off the rails,” Carlson says. “Scientists were telling people summer would be safe. They got it wrong.”

As Carlson points out, a number of rapidly written scientific papers were published in the first months after the outbreak of the pandemic, suggesting there would likely be seasonality to the virus (there’s a nice round-up of the papers here). Most of them were not peer-reviewed, and many were not written by people with an expertise in infectious diseases. “Because a lot of people want to help, a lot of people jumped into this,” Carlson explains.

For example, one widely circulated paper was titled “The Spread of CoV-2 Likely Constrained by Climate,” by Miguel Araujo, a research professor of the Spanish Research Council at the National Museum of Natural Sciences in Madrid, and Babak Naimi, a Finnish geographer. They used a model that looks at ecological niches, or the suitability of a habitat, to hypothesize about where the virus might spread. “The pattern of spread, far from being random, was tightly associated with the climate conditions of the temperate and arid zones during the winter,” the authors wrote. “Our models … support the view that incidence of the virus could follow a seasonal climate pattern … generally being favored by cool and dry weather, while being slowed down by extreme conditions of both cold and heat as well as moist.”

The problem, Carlson and several colleagues wrote in a letter to Nature Ecology & Evolution criticizing the study, is that the scientific methodology used in this paper – known as species distribution modeling, which looks for biological niches where organisms can thrive — doesn’t really apply to the coronavirus, which is spread by human transmission.

“A model [like this] can tell researchers where soil is too acidic for the spores of the anthrax bacterium; where cold temperatures prevent flaviviruses such as dengue or Zika from replicating inside Aedes mosquitoes,” Carlson wrote. But modeling soil for anthrax is not the same thing as predicting how and where humans will spread a virus. Or to put it another way, just because the virus that causes AIDS might not withstand freezing temperatures, it doesn’t mean that it can’t be passed on between two people having sex in Antarctica. As Carlson puts it: “Once an outbreak starts spreading among humans, there is no unsuitable habitat.”

But just because Araujo’s analysis was flawed doesn’t necessarily mean it’s bad science (Araujo didn’t respond to an email request for comment). To Sadie Ryan, a medical geographer at the University of Florida, this is how science is supposed to work. “In the first months of the pandemic, scientists rushed forward with what they had,” she tells me. “You put out an idea, and others build on it or reject it. It’s not supposed to be the end of the story.”

The obvious question: In America, where Trump and his bootlickers have been so shameless about politicizing every aspect of the pandemic, would good science have even made a difference? If the top 100 virologists in the world had marched into the Oval Office last March and announced, “Summer won’t stop the pandemic,” would it have changed anything? Of course not. “We now know the modus operandi of the White House,” Hotez tells me. “They cherry-pick bits of data and statements to fit their narrative with goals to minimize the public perception of the devastation from COVID-19, and embellish their response and achievements.”

And the more desperate the situation becomes, the more the attacks escalate. This week White House economic adviser Peter Navarro savaged Dr. Anthony Fauci in a USA Today op-ed. Hotez calls it “an outright and full-blown anti-science disinformation campaign coming out of the White House.”

The thing about science is that it’s often at war not just with politics, but with human nature. Hard-core deniers like Trump aside, it’s likely that many people believed summer would bring an end to the pandemic simply because they wanted to believe it, because a long summer of death was just too painful to imagine. “We grab on to hopeful ideas,” says Ryan. “Then it’s hard to let them go, even when the data is telling you you should.”

So put on a mask and go outside and soak up the summer vibe. But don’t fool yourself into thinking the heat and sunshine are going to save you from anything.



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