MIAMI - Early in the coronavirus outbreak, word spread that the threat of contagion in would reduce as warmer springtime temperatures swept the northern hemisphere - and by summer covid-19 would be gone.
“When it gets a little warmer it miraculously goes away,” President Donald Trump told one of his last political rallies in February, before retreating to the safety of the podium in the White House briefing room.
Barely a month later doctors and scientists are warning that while several studies have shown climate does have an impact on flu-like viruses, that does not appear to be the case with covid-19, the disease caused by the ‘novel coronavirus.’
“All our (existing) studies on climate involve epidemic diseases. But this is a ‘novel’ pathogen. Meaning it’s new and there is no population immunity,” said Rachel Baker, an expert on climate and infectious diseases at the Princeton Environmental Institute in New Jersey.
“ It’s like a forest fire. It just spreads much more,” she added.
Previous coronavirus epidemics, such as influenza, have circulated for decades allowing immunity to build up in the human population, she explained in a phone interview. “When you have a pandemic like this one there’s no baseline immunity to prevent it. It’s a different animal,” she said.
As a result, she warned that factors such as temperate should be ignored. “I think it’s irrelevant at this stage,” she said.
Confirmed reports of the coronavirus have now surpassed 430,000 cases worldwide, with no signs of slowing down. More than 18,000 people around the globe have already died, the majority in China, Italy and Spain, with the death toll rising over 800 in the United States.
Univision spoke to half a dozen doctors and scientists who confirmed that worried residents should expect little or no relief from warmer temperatures.
“The message is, we don’t know enough. Don’t underestimate this virus,” said Dr Marcos Espinal, director of Infectious Diseases at the Pan-American Health Organization (PAHO) in Washington, the oldest public health agency in the world that is the regional partner in the Americas of the World Health Organization (WHO).
Cases in Latin America
Espinal pointed to a growing number of confirmed coronavirus cases in Latin America, with more than 100 deaths so far, despite currently being at the end of the summer months. Tiny Panama reported 558 cases by Wednesday, with eight deaths, despite having one of the smallest populations in the region and temperatures hovering this week around 90ºF (32ºC).
" Initially we all hoped that the heat and the tropical climate would stop the virus from entering our countries," Dr Xavier Saez-Llorens, a member of the technical committee leading the government's response in Panama, told Univision in a phone interview on Tuesday.
"However, the current evidence indicates that this is not the case ... we have been seeing many cases in our countries, so in truth, this hope we had initially was false. The virus has really entered all of our countries with force,” he added.
As a result, Panama went into total lockdown starting on Wednesday, “similar to Wuhan,” he said, referring to the Chinese city where the virus is believed to have originated and which was closed off to the outside world for weeks.
In sunny Miami cases rising
Cases were also spiraling in sunny Miami, the epicenter of Florida’s outbreak, where the temperature was in the mid-80s on Tuesday.
On Monday, Florida Governor Ron DeSantis expressed concern about reports of people from heavily impacted New York, seeking refuge in South Florida from the coronavirus outbreak.
DeSantis announced on Tuesday that the state was requiring anyone on a flight from the New York City area to self-isolate for 14 days upon arriving in Florida in an effort to control the spread of coronavirus.
The growing number of positive test results in Miami do not reflect what medical professionals are seeing on the ground, according to a letter issued Monday by 75 emergency room doctors, nurses and physicians’ assistants in Miami.
“ The low number of confirmed cases in published reports does not show the true number of people who have been infected by the virus in Miami, or anywhere else in the USA for that matter,” the doctors wrote. “It only reflects where we should be in testing,” they said.
The experts say rather than rely on climate factors, local health authorities needed to heed calls for more containment and mitigation efforts, especially in large cities and major transport hubs where the virus may have traveled from Asia, Europe or the United States.
“ Cases are usually in urban areas and places where there is a lot of travel such as coastal cities,” said Jose Szapocznik, a public health scientist at the University of Miami.
Testing was also lacking in many places, not just the United States, he added, pointing to Russia which has reported only 495 cases and one death.
“The problem with statistics is; garbage in, garbage out. If there is inadequate testing we don't have a clue about transmission,” he said.
“There is a lot of concern about what’s going to happen in large, mega cities in Latin America,” said Gregory Glass, a professor at the University of Florida and a member of the Emerging Pathogens Institute (EPI). “It’s not so much about whether they are better or worse prepared. It’s a big challenge to deliver care in any city. Just look at Europe,” Glass told Univision in a phone interview from his home in Gainesville, central Florida, which went into lockdown on Monday.
The only possible bright spot for Latin America, he said, was the age distribution in the region “which for most countries tends to favor young people.”
“Flu season is coming in South America,” Chile’s ambassador to the United States, Alfonso Silva, told a panel of Latin American diplomats organized by the Atlantic Council on Monday. “We have to vaccinate everyone,” he warned, fearing that “the number of people at risk will be much greater” with a combination of flu and coronavirus.
“No one can guarantee that it’s not going to hit us,” agreed Alexandra Hill, El Salvador’s Minister of Foreign Relations in El Salvador, who participated on the same panel.
Glass and the other experts said key to understanding the impact of climate on covid-19 is learning more about its behavior and how it is being transmitted, as well as its ability to resist environmental conditions.
Scientists say the virus is transmitted by respiratory droplets produced when an infected person coughs or sneezes. These droplets can land directly in the mouths or noses of people who are nearby or on solid objects, such as door knobs and shopping carts, before being passed on indirectly to another person.
Understanding covid-19 transmission
If the virus is passed by touching contaminated objects which it lands on, such as shopping carts, studies of other epidemics show warmer temperatures and more humid conditions could slow its spread due to greater exposure to the environment.
“But, if transmission is really more about close personal contact in families and crowds, then temperature and humidity in the environment probably don’t play much of a role,” said Glass.
In temperate parts of the world, flu tends to have a seasonal pattern with peaks in the winter, as do other milder forms of coronavirus. “ Cold, dry conditions seem to favor the flu virus,” said Baker, who is studying the effects of climate change on viruses.
In the warmer tropics, on the other hand, flu season tends to spread out throughout the year, with some spikes during the rainy season.
Other forms of coronavirus, like the severe acute respiratory syndrome known as SARS, and MERS (the Middle East Respiratory Syndrome) also appeared to thrive in colder temperatures and drier climates.
Early studies of covid-19
Some early evidence from a study of 100 Chinese cities that had more than 400 cases did indicate that the coronavirus was transmitted more rapidly in places with cooler and drier weather conditions. Wuhan, the epicenter of the virus, typically has temperatures in the 40s (Fahrenheit) during December and January.
Another statistical data analysis by two MIT scientists found that 90% of the covid-19 transmissions up until March 21 occurred in regions with temperatures below 17ºC (62.6ºF) and low humidity. However, the authors told Univision that the study was conducted at an early stage in the spread of the virus and it was too early to draw any safe conclusions.
The role of warmer temperature in slowing the spread of the virus “might only be observed, if at all, at much higher temperatures” that would not affect most of the cities in the U.S. and Europe, they observed.
Cultural and human behavior
The authors also said factors such as cultural norms, social distancing measures, and lack of testing may have distorted the number of cases reported in some countries.
Human behavior cannot be discounted either, because people tend to spend more time together indoors in the winter, Baker noted. “ There’s multiple theories out there,” she said. “But the strongest evidence is that it’s all a question of virus survival,” she said.
Added Glass: “We just don’t know how much the virus degrades in the environment.”
Another factor was the size of the dose of the virus needed to infect a potential victim. “Generally, there’s a certain dosage. In this case we don’t know what the dosage is,” he said.
"We won't really know until it's all over"
Finding that out would take time. “We won’t really know until it’s all over, in the after-action report,” he said. In the meantime, quarantine and social distancing were the best defense against transmission.
“We have to act on the side of caution,” he said. “The bottom line is that climate is not going to slow the spread. If that’s what you’re relying on you are whistling past the cemetery,” he added.