Geopolitics

Summer Revisited: Does Warm Weather Reduce COVID-19 Spread?

The number of infections is decreasing in many places, even as restrictions are eased. Vaccines matter, say scientists, but it's not the only factor.

People enjoy a beer garden in Berlin, Germany on June 5, 2021.
People enjoy a beer garden in Berlin, Germany on June 5, 2021.
Birgit Herden

BERLIN — The summer will be good. The horror scenarios of some models have proven to be too pessimistic; even if infections are ticking up in the UK, France and the Netherlands, they are currently falling rapidly across many European countries, despite the easing of restrictions.

People are pouring into cafes and beer gardens, and hope for the end of the pandemic is growing. But one question remains for the time being: Who is doing most of the work to kill the virus: summer or social distancing and vaccines? How much can we celebrate right now?

It has been clear from the start of the pandemic that the spread of the coronavirus is shaped by the change of seasons. Even going all the way back to Hippocrates, we have documented proof that respiratory diseases occur more frequently in winter. However, it has only been understood recently why this is so, and the explanations are by no means trivial. It's not really because of the cold weather that people catch colds. Most people spend a large part of their life in well-tempered interiors anyway, and there are also several respiratory viruses that boom in other seasons.

Various factors influence the spread of respiratory viruses, with humidity playing an important role. Cold air can absorb less humidity than warm air. If you warm up dry winter air in heated rooms, it contains much less water than it could absorb at warm temperatures. The relative humidity — the maximum amount of water that can be stored — is often below 40%.

UV rays destroy viruses.

Humidity affects the spread of many viruses. Just as laundry dries quickly in heated rooms, the droplets that people spray with every breath and every word release some of the water they contain into the air. They become lighter, no longer sinking to the ground but rather floating in space for a long time, ready to be inhaled by other people. Accordingly, infections often occurred in closed rooms during the pandemic.

At the same time, air with low relative humidity attacks the protective barrier that lines our airways — a tricky arrangement of mucus and cilia. The upper layer of the slimy coating is relatively tough, so foreign substances and pathogens get stuck in it. The lower layer is thinner and is driven by the fine cilia of the mucous membrane cells.

In this way, viruses stuck to the top layer are transported towards the larynx, swallowed and destroyed by stomach acid before they enter the body. However, this does not work as well if the slimy barrier becomes thinner in dry air.

A woman wearing a mask passes a COVID testing center in Berlin — Photo: Fabian Sommer/DPA/ ZUMA Press

Beyond temperature and humidity, solar radiation also affects the spread of cold viruses: UV rays destroy viruses. In addition, many people have a vitamin D deficit in winter, which can be unfavorable for the immune system.

All of these factors affect the virus's occurrence. In the tropics, for example, there are no flu seasons, but a slight risk of infection all year round. In New York, the spread of flu viruses will be reduced by 40% in the summer, in Florida by only 20%. Things are made even more complicated by human behavior. If, for example, many people are in air-conditioned rooms in hot summers, this can probably weaken the summer effect.

In addition, winter waves can be bigger if our immune systems were challenged very little during a virus-free summer. For example, some experts fear that the flu wave in Germany could be particularly severe in the coming winter after it has been weak one year and almost inexistent another. On top of that, the various cold viruses compete with each other in their undulating ups and downs and can displace one another.

The seasonal effect alone would not be strong enough to make the virus disappear completely.

So, it's no wonder that it has been difficult to predict how the seasons would affect the pandemic. The observation that the virus can spread in countries such as Brazil and India even in warm weather is of little help — their conditions can hardly be compared with the European change of seasons.

At the same time, it quickly became clear that the seasonal effect alone would not be strong enough to make the virus disappear completely during the summer months, as is known from the annual flu waves. Because its infectivity within a population without basic immunity is simply too great for that. So, for example, in the United States, the number of infections was particularly high last summer.

Accordingly, it is difficult for modelers to include the influence of the seasons in their scenarios. Many assume that the summer reduces the prevalence of the virus by about 20%. The source is research led by the American epidemiologist Marc Lipsitch from Harvard University published in May 2020. Lipsitch came up with the figure while analyzing the winter waves of the older, harmless coronaviruses.

In his scenarios for the course of the COVID-19 pandemic, however, he said the number would be in a range of between 0 to 40 percent. A year later, he still can't provide any other information as he has not dealt with this question since then. "With COVID-19, it is difficult to unravel the effects of the seasons, measures and behavioral change," he says. "All hypotheses will remain only provisional."

Research on the impact of the seasons on the pandemic has been sparse and contradictory. Different studies say the summer can reduce the presence of the virus by between less than 20% to 60%. It only seems clear that the seasonal effect is stronger with increasing latitude.

"As long as we can't quantify the impact of non-pharmaceutical measures and social factors, we don't need to deal with seasonality from my point of view," says Matthias Linden, a theoretical physicist who works in Viola Priesemann's group at the Max Planck Institute.

Even if the summer effect cannot be quantified — the figures, which are currently falling so rapidly, don't suggest a particularly strong seasonality, Linden says. Completely unchecked, the original coronavirus had a reproduction number of around three in winter — which means that is one infected person infected on average three other people. With the more infectious variant B.1.1.7, the number is at least four.

We can ease restrictions carefully, and step-by-step, enjoy summer

Whatever has prevented an explosion of cases in winter — whether restrictions or voluntary caution — has lowered the reproduction number to 1, an 80% decrease. The vaccine has further reduced it by about 30%, although its effect has been counteracted by easing restrictions.

Summer is here, the public mood is improving and some people forget the reasons that led to restrictions: they keep no distance, no masks, and organize parties. The German left-leaning member of Parliament and epidemiologist Karl Lauterbach warns the people have become too reckless and expect a fourth wave of infections to take Europe by storm in the fall.

The reproduction number has sunk below one, the wave ebbs. Even small differences due to seasonality cause big changes in this phase. With a reproduction number of 0.8, infections halve within two weeks; at 0.7, the same thing happens in the space of one week.

"To assume that the measures play no role at all would be nonsensical, just like the idea that seasonality has only a very small or no influence on the number of infections," says Berlin epidemiologist Kai Schulze. So there is only one thing to do: we can ease restrictions carefully, step by step, and enjoy the summer. But meanwhile, we have to vaccinate anyone we can until autumn — that way we'll keep the winter wave small.

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New Delhi, India: Fumigation Against Dengue Fever In New Delhi

Anne-Sophie Goninet, Jane Herbelin and Bertrand Hauger

👋 வணக்கம்*

Welcome to Thursday, where America's top general reacts to China's test of a hypersonic weapon system, Russia is forced to reimpose lockdown measures and Venice's historic gondola race is hit by a doping scandal. French daily Les Echos also offers a cautionary tale of fraud in the crypto economy.

[*Vaṇakkam, Tamil - India, Sri Lanka, Singapore]

💡  SPOTLIGHT

A dove from Hiroshima: Is Fumio Kishida tough enough to lead Japan?

Japan's new prime minister is facing the twin challenges of COVID-19 and regional tensions, and some wonder whether he can even last as long as his predecessor, who was forced out after barely one year.

When Fumio Kishida, Japan's new prime minister. introduced himself earlier this month, he announced that the three major projects of his premiership will be the control of the ongoing pandemic; a new type of capitalism; and national security.

Kishida also pledged to deal with China "as its neighbor, biggest trade partner and an important nation which Japan should continue to dialogue with."

Nothing too surprising. Still, it was a rapid turn of events that brought him to the top job, taking over for highly unpopular predecessor, Yoshihide Suga, who had suddenly announced his resignation from office.

After a fierce race, Kishida defeated Taro Kono to become the president of the ruling Liberal Democratic Party (LDP), and pave the way for the prime minister's job.

A key reason for Kishida's victory is the improving health situation, following Japan's fifth wave of the COVID pandemic that coincided with this summer's Olympic Games in Tokyo.

The best way to describe Kishida is to compare him to a sponge: not the most interesting item in a kitchen, yet it can absorb problems and clean up muck. His slogan ("Leaders exist to make other people shine") reflects well his political philosophy.

Kishida was born into a political family: His grandfather and father were both parliament members. Between the ages of six to nine, he studied in New York because of his father's work at the time. He attended the most prestigious private secondary school — the Kaisei Academy, of which about half of its graduates go to the University of Tokyo.

However, after failing three times the entrance exam, Kishida finally settled for Waseda University. Coming from a family where virtually all the men went to UTokyo, this was Kishida's first great failure in life.

After he graduated from college, Kishida worked for five years in a bank before serving as secretary for his father, Fumitake Kishida. In 1992, his father suddenly died at the age of 65. The following year, Kishida inherited his father's legacy to be elected as a member of the House of Representatives for the Hiroshima constituency. Since then, he has been elected successfully nine straight times, and served as Shinzo Abe's foreign minister for four years, beginning in December 2012. A former subordinate of his from that time commented on Kishida:

"If we are to sum him up in one sentence, he is an excellent actor. Whenever he was meeting his peers from other countries, we would remind him what should be emphasized, or when a firm, unyielding 'No' was necessary, and so on ... At the meetings, he would then put on his best show, just like an actor."

According to some insiders, during this period as foreign minister, his toughest stance was on nuclear weapons. This is due to the fact that his family hails from Hiroshima.

In 2016, following his suggestion, the G7 Ise-Shima Summit was held in Hiroshima, which meant that President Barack Obama visited the city — the first visit by a U.S. president to Hiroshima, where 118,661 lives were annihilated by the U.S. atomic bomb.

In September 2020 when Shinzo Abe stepped down as prime minister, Kishida put out his candidacy for the first time for LDP's presidency. He didn't even get close. This was his second great failure.

But reading his biography, Kishida Vision, I must say that besides the two aforementioned hiccups, Kishida's life has been smooth sailing over the past 64 years.

When one has had a happy and easy life, one tends to think that human nature is fundamentally good. Yet, the world doesn't work like that. And Japanese tend to believe that "human nature is vice," and have always felt a bit uneasy with the dovish Kishida diplomacy when he was foreign minister.

Hiroshima has always been a city with a leftist political tradition. Kishida's character, coupled with the fact that he belongs to the moderate Kochikai faction within the LDP, inevitably means that he won't be a right-wing prime minister.

Kishida would never have the courage to be engaged in any military action alongside Japan's ally, the United States, nor will he set off to rewrite the country's constitution.

So after barely a year of Yoshihide Suga in office, how long will a Fumio Kishida government last? If Japan can maintain its relatively stable health situation for some time, it could be a while. But if COVID comes roaring back, and the winter brings a sixth wave of the pandemic as virtually all Japanese experts in infectious diseases have predicted, then Kishida may just end up like Suga. No sponge can clean up that mess.

Daisuke Kondo / Economic Observer

🌎  7 THINGS TO KNOW RIGHT NOW

Top U.S. general says Chinese weapon nearly a "Sputnik moment": China recently conducted a "very concerning" test of a hypersonic weapon system as part of its push to expand space and military technologies, Gen. Mark Milley, the U.S. Chairman of the Joint Chiefs of Staff, told Bloomberg News. America's top military officer said that this was akin to the Soviet Union's stunning launch of the world's first satellite, Sputnik, 1957, which sparked the Cold War space race. Milley also called the test of the weapon "a very significant technological event" that is just one element of China's military capabilities.

Brexit: France seizes British trawler: A British trawler has been seized by France while fishing in French waters without a license, amid escalating conflict over post-Brexit fishing rights. France's Minister for Europe said it will adopt a zero-tolerance attitude towards Britain and block access to virtually all of its boats until it awards licenses to French fishermen.

COVID update: Russia confirmed a new record of coronavirus deaths, forcing officials to reimpose some lockdown measures, including a nationwide workplace shutdown in the first week of November. Germany also saw its numbers spike, with more than 28,000 new infections yesterday, adding to worries about restrictions this winter there and elsewhere in Europe. Singapore, meanwhile, reported the biggest surge in the city-state since the coronavirus pandemic began. Positive news on the vaccine front, as U.S. pharmaceutical giant Merck granted royalty-free license for a COVID-19 antiviral pill to help protect people in the developing world.

Iran nuclear talks to resume: Iran's top nuclear negotiator said multilateral talks in Vienna with world powers about its nuclear development program will resume before the end of November. The announcement comes after the U.S. warned efforts to revive the deal were in "critical phase."

First U.S. passport with "X" gender marker: The U.S. State Department has issued its first American passport with an "X" gender marker. It is designed to give nonbinary, intersex and gender-nonconforming people a marker other than male or female on their travel document. Several other countries, including Canada, Argentina and Nepal, already offer the same option.

China limits construction of super skyscrapers: China has restricted smaller cities in the country from building extremely tall skyscrapers, as part of a larger bid to crack down on wasteful vanity projects by local governments. Earlier this year the country issued a ban on "ugly architecture."

Doping scandal hits Venice's gondola race: For the first time in the history of the Venice Historical Regatta, a participant has tested positive to marijuana in a doping test: Gondolier Renato Busetto, who finished the race in second place, will be suspended for 13 months.

🗞️  FRONT PAGE

"End of the ice age," titles German-language Luxembourgish daily Luxemburger Wort, writing about how the ice melting in the Arctic opens up new economic opportunities with a new passage for countries like Russia and China but with potentially devastating effects for the environment. The issue of the Arctic is one of the topics that will be discussed at the COP26 Climate Change Conference which kicks off in Glasgow on Sunday.


#️⃣  BY THE NUMBERS

$87 billion

A new United Nations report found that extreme weather events such as tropical cyclones, floods and droughts have caused India an average annual loss of about $87 billion in 2020. India is among the countries which suffered the most from weather hazards this year along with China and Japan.

📰  STORY OF THE DAY

Air Next: How a crypto scam collapsed on a single spelling mistake

It is today a proven fraud, nailed by the French stock market watchdog: Air Next resorted to a full range of dubious practices to raise money for a blockchain-powered e-commerce app. But the simplest of errors exposed the scam and limited the damage to investors. A cautionary tale for the crypto economy from Laurence Boisseau in Paris-based daily Les Echos.

📲 The story began last February, when Air Next registered with the Paris Commercial Court. The new company stated it was developing an application that would allow the purchase of airline tickets by using cryptocurrency, at unbeatable prices and with an automatic guarantee in case of cancellation or delay, via a "smart contract" system. Last summer, Air Next started recruiting. The company also wanted to raise money to have the assets on hand to allow passenger compensation.

📝 On Sept. 30, the AMF issued an alert, by way of a press release, on the risks of fraud associated with the ICO, as it suspected some documents to be forgeries. For employees of the new company, it was a brutal wake-up call. They quickly understood that they had been duped, that they'd bet on the proverbial house of cards. Challenged by one of his employees on Telegram, the CEO admitted that "many documents provided were false", that "an error cost the life of this project."

⚠️ What was the "error" he was referring to? A typo in the name of the would-be bank backing the startup. A very small one, at the bottom of the page of the false bank certificate, where the name "Edmond de Rothschild" is misspelled "Edemond". Before the AMF's public alert, websites specializing in crypto-assets had already noted certain inconsistencies. The company had declared a share capital of 1 billion euros, which is an enormous amount. Air Next's CEO also boasted about having discovered bitcoin at a time when only a few geeks knew about cryptocurrency.


➡️ Read more on Worldcrunch.com


📣 VERBATIM

"A weapon was handed to Mr. Baldwin. The weapon is functional, and fired a live round."


— Following the Oct. 21 on-set shooting death of cinematographer Halyna Hutchins, Sante Fe County Sheriff Adan Mendoza told a press conference that the "facts are clear" about the final moments before Hutchins was shot. The investigation continues to determine what led up to that moment, and any possible criminal responsibility related to how the "prop" gun that actor Alec Baldwin fired was loaded.

📸  PHOTO DU JOUR

Fumigation is used as a precautionary measure against the spread of dengue disease in New Delhi, India, where more than 1,000 cases have been reported — Photo: Naveen Sharma/SOPA Images/ZUMA

✍️ Newsletter by Anne-Sophie Goninet, Jane Herbelin and Bertrand Hauger

Share with us your favorite gondola memories or worst crypto scams — and let us know what the news looks like from your corner of the world! - info@worldcrunch.com

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