The novel coronavirus pandemic leaves many questions unanswered, one of which is why there are significantly fewer deaths in Asia than in Western Europe and North America.
Even when technical factors such as detection policies and counting methods are taken into account, significant differences in mortality rates around the world have attracted the attention of countless researchers trying to crack the virus code.
Medical experts quoted by the BBC said the same virus did not appear to have mutated significantly as a result of transmission, and the difference in death rates was surprising.
In addition to the rapid response and early initiation of social isolation measures in parts of Asia, scientists are also analyzing other factors, such as differences in genetic and immune response, different strains of the virus, and regional comparisons of obesity levels and overall health, the Washington post said.
Over the past few months, novel coronavirus has demonstrated its innate infectivity and lethality around the world.
Scientists at chiba university in Japan mapped the virus’s path around the world, with wide variations from region to region.
So far, fewer than 5,000 people have died in China, or three deaths per million people, according to newsmax.
The ratio is about seven parts per million in Japan, six parts per million in Pakistan, five parts per million in South Korea and Indonesia, three parts per million in India and less than one part per million in Thailand.
By comparison, covid-19 kills about 100 people per million in Germany, about 180 in Canada, nearly 300 in the United States and more than 500 in the United Kingdom, Italy and Spain.
Why are the virus fatality rates so different from region to region?
Jeffrey Shaman, an epidemiologist at Columbia University in the us, was baffled. “our immune response pool and its vulnerabilities are almost the same,” he said.
Part of the reason for the high death toll in Europe and the us could be the initial failure to respond to a seemingly remote epidemic, according to the Washington post.
In contrast, in Asia, the experiences of SARS and MERS have enabled some countries to respond more quickly.
But Japan and India were slow to respond, and their relatively low death tolls confused many scientists.
A study by the medical team at the university of Cambridge showed differences between east Asia and Europe.
A team of scientists at the los alamos national laboratory also suggests that a more contagious virus has taken root in Europe and spread in the United States.
But other experts say the exact nature of the new strain of the virus remains unclear.
“It could have been an accident, with ‘superinfected’ people going to rock festivals and nightclubs and spreading the virus to most people;
But another possibility is that the strain becomes more easily transmissible.”
Jeremy Luban, a virologist at the university of Massachusetts medical school.
Peter Forster, a British geneticist, agrees that clinical data on how different viral strains interact with different populations is still too limited to explain the link to differences in mortality.
The immune system
Japanese immunologist and Nobel laureate yuke honshu told the Washington post that Asian and European ancestry showed significant differences in the haploid form of human leukocyte antigen, a gene that controls the immune system’s response to viruses.
That may help explain Asia’s lower death rates.
The university of chiba scientists believe that a range of genetic factors may influence the body’s response to the virus and that further research is warranted.
At the same time, a different immune response seems to be at work.
The Japanese immune system tends to react to novel coronaviruses, which have been circulating in east Asia for hundreds of years, said Tokyo university researcher tatsuhiko koda, citing a preliminary study.
The mystery of low death rates in east Asia can be explained by the presence of the immune system.
Other studies have suggested that BCG vaccination may offer some protection, since anti-tb vaccines may induce an immune-boosting response at the cellular level.
But researchers at fujita health university in Japan also point out that the record of BCG vaccination in Japan is similar to that in France, where mortality rates are very different.
“Another factor worth investigating is differences in the microbial community — the trillions of bacteria in the human gut that play a huge role in the immune response.”
Megan Murray, an epidemiologist at harvard medical school, says different regions have different diets, and their microbial communities vary widely.
Climate, demographics, lifestyle and obesity rates are also under scrutiny, but there are always some puzzling counterexamples to be found.
First, in places such as Cambodia, Vietnam and Singapore, hot and humid weather is seen as a potential plus.
Several studies have shown that heat and humidity can at least slow the spread of the virus.
But the steady stream of confirmed and fatal cases in some equatorial countries, including Ecuador and Brazil, has thrown that view into question.
Second, demographics also play a role in regional differences.
For example, Africa’s overall younger population may be more resistant than older communities in northern Italy.
But Japan has the world’s oldest population, and people are looking for different reasons to control the virus.
Many experts point out that good hygiene practices, such as wearing masks and avoiding handshakes, have helped slow the spread of the virus, and that the national health care system and the country’s emphasis on protecting the elderly may have reduced the death toll.
What’s more, obesity has also been studied.
Obesity rates in many Asian countries are much lower than in the west, and obesity is considered a high risk factor for severe illness and complications.
Obesity is just over 4 percent in Japan, less than 5 percent in South Korea, more than 20 percent in Western Europe and 36 percent in the United States, according to the world health organization.
So far, however, any epidemiological studies of the virus have been based on incomplete data.
As the Washington post points out, any conclusions could be overturned as new data emerge.
Experts cautioned that the novel coronavirus pandemic was still in its early stages and that it would take time to solve scientific puzzles.
No matter how different the death rates are around the world, there is no reason for each country to let its guard down.