Four elements to understand the different spread of the virus – Hanna Beech

In Iran, the covid-19 killed so many people that the government was forced to bury them in mass graves. In neighboring Iraq, however, the victims are less than one hundred. The Dominican Republic has registered almost 7,600 cases of contagion, but beyond the border, in Haiti, the number has stopped at 85. In Indonesia, thousands of people are believed to have died from the epidemic, while in neighboring Malaysia’s series of extremely rigid measures kept deaths at around one hundred.

Covid-19 has affected almost every country in the world, but its impact seems extremely erratic. Where world metropolises like New York, Paris and London have been devastated, megacities like Bangkok, Baghdad, New Delhi and Lagos have been saved substantially. At least until now.

The fact that the virus has swept some areas of the planet leaving others almost unharmed is an enigma that has fueled a series of theories and conjectures, without producing any definitive answer. Understanding this phenomenon could have profound consequences on how countries deal with the epidemic, making it possible to determine who is most at risk and when it will be possible to resume a normal appearance of life.

Thesis and denials
Right now, hundreds of investigations are underway in the four corners of the planet on the possible effects of demographic conditions, previous diseases and genetic characteristics.

In Saudi Arabia, doctors assess the possibility that genetic differences affect the severity of covid-19 symptoms, while Brazilian scientists analyze the relationship between genes and complications of the disease. In several countries, researchers are testing a theory that high blood pressure medications could worsen the severity of covid-19, while a specific tuberculosis medication could have the opposite effect.

The fact that many developing countries with hot climates and a young population have been spared the most catastrophic consequences of the virus suggests that temperature and demographics are determining factors, but this thesis is denied by the large number of cases in the countries. . tropical like Peru, Indonesia and Brazil.

In general, the appropriate measures to impose social distancing and the blocking of activities have been effective. However, two countries like Cambodia and Burma, where strict isolation measures have not been taken, have experienced a small number of infections.

In this sense, there is a theory that has not been proven, but it is impossible to refute: perhaps the virus has not yet affected these countries. Initially, Russia and Turkey seemed unharmed, but then the situation suddenly precipitated.

There is always a chance that time will erase these differences. The Spanish fever that hit the United States in 1918 seemed to have disappeared over the summer, but it came back much more vehemently the following fall and then again in a third wave the following year. Eventually, the virus reached remote places like the islands of Alaska and the South Pacific, infecting a third of the world’s population.

“We are still at an early stage of the epidemic,” confirms Dr. Ashish Jha, director of the Harvard University Institute for Global Health Research. “If it was a baseball game we would be in the second inning. We do not know if in the ninth inning the countries that currently seem free will have the same conditions as the others. ”

Doctors studying infectious diseases worldwide point out that they do not have enough data to compose a complete epidemiological picture. In many countries, lack of information makes any conclusion dangerous. Sample analysis is often performed slowly, and this creates a strong underestimation of the number of infections. Deaths from covid-19 are almost certainly much more numerous than those recorded.

However, the general trends seem quite clear. A country may have enormous administrative difficulties and an inefficient health system, but it is still difficult to hide mass graves or hospitals that reject thousands of patients.. Therefore, it is undeniable that several countries are not experiencing a dramatic situation. At the time.

According to the statements of some twenty infectious disease experts, health officials, epidemiologists and academics from around the world, there are four factors that could help explain where the virus thrives and where it encounters difficulties: demographics, culture, environment and speed of response. from the authorities.

However, every possible explanation is accompanied by abundant reservations and evidence that seems to contradict it. If a larger population is automatically more vulnerable, for example, Japan should be at the top of the infection list. But that is not the case at all. In any case, these are the factors that experts believe are most compelling.

the power of youth
Many countries saved from a massive epidemic have relatively young populations. According to Robert Bollinger, professor of infectious diseases at Johns Hopkins University medical school, young people are more likely to be asymptomatic or have mild symptoms and transmit the virus less frequently. Furthermore, according to the World Health Organization (WHO), young people have a lesser tendency to develop a series of problems that can increase the mortality of covid-19, the disease caused by the Sars-cov-2 virus.

Africa, where 45 thousand confirmed cases represent an infinitesimal portion of the 1.3 billion inhabitants, is the youngest continent in the world. 60 percent of the African population is under 25 years old. In Thailand and the Iraqi city of Najaf, local health authorities have verified that the 20-29 age group has the highest rate of infection, but often does not develop particular symptoms.

In contrast, the average age of Italy, one of the most affected countries, is over 45 years old, while the average age of the victims is around 80 years old.

Younger people tend to have a firmer immune system that can reduce symptoms of the disease, says Josip Car, a global health expert at Nanyang Technical University in Singapore.

In Saudi Arabia and Singapore, for example, most of the infection affects migrant workers, many of whom live in crowded dormitories. However, they are often young, healthy people who have not needed hospitalization.

According to some EE researchers. In the USA, good health, along with an early age, can lessen the impact of the virus, while some pre-existing diseases (hypertension, diabetes and obesity) can worsen its effects.

However, there are significant exceptions to demographic theory. Japan’s population is the oldest in the world, but the country has experienced fewer than 520 deaths, although the number of cases has increased with the intensification of sample analyzes.

The Ecuadorian region of Guayas, the epicenter of an outbreak that could have resulted in the death of 7,000 people, has one of the youngest populations in the country: people over 60 years old represent only 11 percent of the population.

Dr. Jha notes that some asymptomatic youth remain extremely contagious, for reasons that are not yet clear at this time.

Cultural distancing
According to epidemiologists, cultural factors such as the natural tendency of some societies to keep their distance may have protected some states more.

In Thailand and India, where the number of viruses is relatively low, people greet each other without contact, reaching for the palms of their hands as they do in prayers. In Japan and South Korea, people greet each other with a bow, and even before the advent of the covid-19, they often wore masks in case of discomfort.

In most developing countries, the habit of caring for the elderly in the family has reduced the number of nursing homes, structures that in the West have been fertile ground for the epidemic.

But even in this case there are important exceptions. In many Middle Eastern countries, such as Iraq and the Persian Gulf states, men have a habit of hugging and shaking hands. However, infections are rare.

Another advantage could derive from the so-called “national distancing”: relatively isolated countries have experienced positive health effects.

Remote states like those of the South Pacific or sub-Saharan Africa, for example, have not been invaded by foreigners who brought the virus with them. According to African health experts, the reduced number of international trips is the main reason for the low infection rate on the continent.

The least accessible countries for political reasons (such as Venezuela) or armed conflict (Syria and Libya) have been protected from the relative absence of travelers. The same is true of countries like Lebanon and Iraq, marked by violent protests in recent months. Furthermore, the lack of public transportation in developing countries could be another element that has limited the spread of the virus.

Heat and light
The geography of contagion, which spread rapidly during the winter in temperate countries like Italy and the United States, while it was practically absent in hot countries like Chad or Guyana, seems to suggest that the virus does not like heat. Other coronaviruses, such as those that cause the common cold, are less contagious in hot, humid climates.

However, according to the researchers, the idea that warm weather is enough to repel the virus is an illusion. In fact, some of the worst outbreaks in developing countries have exploded in areas like the Brazilian Amazon, where the climate is tropical. “The most compelling hypothesis is that summer weather contributes but is not enough to slow the increase in cases or cause a decrease,” explains Marc Lipsitch, director of the Center for Communicable Disease Dynamics at Harvard University.

According to Dr. Raul Rabadan, a computational biologist at Columbia University, the virus that causes covid-19 appears to be so contagious that it mitigates any beneficial effects of heat and humidity. However, other aspects related to hot climates, such as the tendency to spend more time outdoors, could have positive effects. “Living indoors can encourage virus recirculation, increasing the chance of contracting the disease,” says Dr. Car.

According to a study by some ecological modeling specialists at the University of Connecticut, ultraviolet rays from direct sunlight inhibit Sars-cov-2. This means that surfaces are more difficult to contaminate in sunny places. But the fact is, transmission usually occurs through contact with an infected person, not a surface.

Unlike Donald Trump, no scientist has claimed that projecting light rays into an infected person can be an effective cure. Also, the tropical climate may have created a false sense of security for some people. “Here people said ‘there is no, we cannot take it,'” says Ecuadorian researcher Doménica Cevallos. “Some went out to sunbathe, convinced that this would protect them from infection.”

Timely and rigid locking
Countries that quickly introduced isolation measures, such as Vietnam and Greece, have avoided out-of-control contagion. These data demonstrate the effectiveness of social and physical distancing and quarantine in containing the virus.

In Africa, countries that have accumulated some experience with life-threatening diseases such as AIDS, drug-resistant tuberculosis and Ebola were better prepared and reacted quickly.

In countries like Uganda and Sierra Leone, airport staff began wearing masks, tracking contacts, and measuring temperature (a measure that, in the meantime, has proven less effective than expected) much earlier than the United States and European countries. .

Senegal and Rwanda closed their borders and announced a curfew when there were still few cases of contagion. In both countries, the ministry of health quickly began procedures to locate contacts.

All of this happened in a region where health care funds, staff and equipment depend on the generosity of foreign countries, many of which are currently focused on the health emergency within their borders, emphasizes African Executive Director Catherine. Kyobutungi. population and health research center.

“Governments wake up one day and understand that the weight of the whole country is now on their shoulders and therefore they have to do it alone,” explains Kyobutungi. “In the end they proved to be up to the task. I have to admit, some of the responses have been exciting.”

Sierra Leone has adapted protocols to detect diseases developed during the 2014 Ebola epidemic, which claimed the lives of almost 4,000 people. The government has established emergency operations centers in each district and has hired 14,000 health workers, including 1,500 trained to trace contacts, even though Sierra Leone has recorded only 155 cases.

However, it is not yet clear who will pay the wages and equipment, such as motorcycles and raincoats, which is essential during the rainy season just around the corner.

Uganda, another country affected by the Ebola epidemic, quickly quarantined Dubai travelers after confirming that the first case of infection had come from the emirate. Authorities located another 800 travelers who had arrived from Dubai in the previous weeks. Health workers in the country are testing more than 1,000 truckers a day. However, most of the infected people come from Tanzania and Kenya, two countries that do not carry out equally intense monitoring. This fears that the infection may spread across the country’s borders, far from being robust.

According to the WHO, isolation measures, with the ban on religious and sporting events, are clearly effective. More than a month after the closure of national borders, schools and most commercial activities, countries like Thailand and Jordan have experienced a collapse in new cases of contagion.

In the Middle East, the closure of mosques, temples and churches has been quite timely and has probably helped stop the epidemic.

A notable exception is represented by Iran, which waited on March 18 before closing its most important places of worship, or a month after the confirmation of the first case in the holy city of Qom. Since then, the epidemic has spread rapidly, killing thousands of people and spreading the virus across borders, through pilgrims returning home.

However, effective blockade measures are, in countries where adequate social assistance is lacking and where most people depend on the informal economy, it will be difficult to maintain commercial closure and domestic isolation. When people are forced to choose between social distancing and the possibility of feeding their families, they generally have little doubt.

Interestingly, some countries where authorities reacted late and in attacks and startups appear to have gotten rid of the virus. In a context marked by the few measures of social distancing, Cambodia and Laos have been hit by small waves of contagion, but they have not registered new cases for three weeks.

Lebanon, from which many Muslim and Christian pilgrims leave for countries overwhelmed by the virus, such as Iran and Italy, should present a widespread contagion, but this is not the case. “We are not collecting the data we expected,” explains Dr. Roy Nasnas, a consultant specializing in infectious diseases at Geitaoui University Hospital in Beirut. “We cannot explain it.”

The case
Most experts agree that there may not be a single reason why one country is hit hard while another is saved. The cause of the phenomenon is probably a combination of the factors discussed, along with a last element often cited by researchers: pure chance.

Countries with similar cultures and climates can present radically different situations: it is enough for a single infected person to participate in a particularly busy social event, triggering what researchers call a “super-diffuse” event.

This is exactly what happened when a passenger infected 634 people on board the Diamond Princess cruise ship off the coast of Japan; or when an infected man attended a funeral in Albany, Georgia; or even when a 61-year-old woman entered a church in Daegu, South Korea, transmitting the virus to hundreds of people who in turn infected thousands of Koreans.

Since an infected person may show no symptoms for a week or even longer (not to mention asymptomatic), the virus spreads exponentially and no one can detect it, following an apparently random path. If the Daegu woman had stayed home that Sunday in February, the number of epidemics in South Korea may have halved today.

However, some countries that were supposed to be swept away by the virus right now are not, and researchers can’t find a reason.

In mid-January, Thailand registered the first case of contagion outside of China. He was a traveler from Wuhan, the city where the pandemic is believed to have originated. In those crucial weeks, Thailand has continued to receive visitors from China, but for some reason tourists have not caused an exponential outbreak.

Some countries seem to have made all the possible mistakes, but have not been overwhelmed by the virus as expected. For many it remains a mystery.

“In Indonesia we have a health minister who is convinced that we can recover from covid-19 by praying, and we practically do not take samples,” says Dr. Pandu Riono, an infectious disease specialist at the University of Indonesia. “But we are fortunate to have many islands and this limits displacement and even infections. Aside from the islands, however, we are doing everything wrong. ”

(Translated by Andrea Sparacino)