The pandemic of 1918 swept the world, and today we know far more about the flu than we did 20 years ago, let alone half a century or a century ago. But it's still far from full mastery. Jeffery Taubenberger, a pathologist at the National Institute of Allergy and Infectious Diseases, and his colleague Ann Reid analyzed nine RNA "fragments" from the flu virus, published in Science in 2005. At a recent meeting, Taubenberg noted that there are still many unanswered questions.
Researchers around the world are working to answer these questions. But the mysteries they've revealed can be shocking.
The stronger the body, the more susceptible it is to infection
In October 1918, Austrian painting giant Egon Schiele died of influenza, just three days before his six-month-pregnant wife, Edith. In the last days of his life, despite Schiller's critical illness and grief, the painter struggled to create a work depicting a family of three, and this is Schiller's own family, which is about to be swept away by the flu.
Schiller was 28 years old, at an age that was very vulnerable to the 1918 flu. So Schiller's unfinished work "The Family" is often called a poignant testimony to the cruelty of the flu.
In this pandemic, young people aged 20 to 40 have the highest mortality rate. A large number of young adults who earn money to support their families and the pillars of the community have been killed by the pandemic, leaving countless elderly and orphans helpless. Overall, men are more likely to catch the flu and die from this flu than women, unless they are pregnant women. At that time, a large number of pregnant women either died or miscarried.
Scientists don't know why people in their prime have the highest death rates from this flu, because older people are usually at high risk for the flu. One possible clue is that the death rate of older adults before the 1918 pandemic was indeed lower than the multiple seasonal flu they experienced in the past decade.
A theory called "original antigenic sin" (OAS) in the human body may explain both of these observations. This theory says that the immune response produced by the human immune system after encountering the first influenza virus is most effective against this first encounter virus. However, influenza viruses are extremely unstable and mutate all the time (including two major types of nucleoprotein antigens on the surface of epidemic A viruses, abbreviated as H and N) to deal with the host's immune system.
Part of the empirical evidence shows that the first wave of influenza virus subtype H3N8 infected young people who died in 1918 was H3N8, but the 1918 influenza pandemic was caused by the influenza virus subtype H1N1, which shows that young people at that time were faced with a very different virus and could not resist. According to this reasoning, there was also an outbreak of influenza in the world in 1830, the influenza virus was H1 or N1 subtype antigen, and the elderly in 1918 experienced the flu, so they had a certain resistance to the H1N1 virus in the 1918 influenza.
Fatality rates vary widely around the world
The global flu outbreak is sometimes called the national plague (everyone is infected, regardless of the nobility), but the 1918 pandemic was far from it. For example, if you live in some parts of Asia, the fatality rate is 30 times higher than in some parts of Europe.
Overall, influenza deaths are highest in Asia and Africa, and lowest in Europe, North America and Australia, but the situation varies widely within continents. In Denmark, influenza accounts for 0.4% of the total population, while in Hungary, the death rate is about three times that of Denmark. Cities tend to suffer more than rural ones, but there are also urban-to-urban differences.
This inequality was already vaguely felt, but it took statisticians decades to provide conclusive data. Once completed, they realized that the disparity in mortality should come from differences in group populations, especially socioeconomic factors.
In the US state of Connecticut, for example, the latest immigrants were Italians and had the highest number of deaths, while in Rio de Janeiro, once Brazil's capital, shanty towns were hardest hit.
A perplexing phenomenon has occurred in Paris, with some of the upper-income districts recording the highest death rates. In the end, statisticians figured out that it was not the owners of the mansions who died of the flu, but their overworked maids, who slept at night in the cold attic under the roof.
Worldwide, the poor, immigrants and ethnic minorities are more vulnerable to infection, not because they are physically inferior, as eugenicists claim, but more likely because they do not eat well, live in crowded housing, suffer from other diseases themselves, and have limited access to medical care.
The above situation has not improved significantly. A study of the UK's 2009 influenza pandemic showed that among the poorest quintiles, the death rate was three times higher than among the rich.
It's not just respiratory diseases
Most of those infected with the Spanish flu have recovered, but among the poor who have fallen to the ground, the flu is coming quickly and onset quickly – at least 25 times as many as other flu outbreaks.
After infection, the patient began to have difficulty breathing, his face was cyanosis, he turned reddish and purple — medically known as "lilac cyanosis" — and died blue all over. In almost all cases, the cause of death is not the influenza virus, but the complicated Streptococcus pneumoniae, which invades the lungs infected by the influenza virus, causing symptoms belonging to pneumonia, the "special friend" of the elderly.
The above situation about the Spanish flu is well known in the world. But little is known about the fact that influenza can affect the entire human body. Hair loss and loose teeth, causing dizziness, insomnia, hearing loss, loss of smell, decreased vision. There are even psychotic sequelae, especially "melancholia", or as it is now called, post-viral depression.
There is continuing evidence that influenza pandemics and common seasonal influenza lead to high rates of death, followed by large numbers of deaths from other causes, particularly heart disease and stroke, which are complicated by inflammation caused by influenza. Influenza is not just a respiratory disease, it was so in 1918, and it is still the case.
The Spanish flu pandemic has changed human perceptions of public health
Eugenics was the dominant view of society before and after the emergence of the 1918 pandemic, but it was shaken up in at least one area: infectious diseases.
Previously, social Darwinists mistakenly believed that some "races" or classes were superior to others, and they confused this view with the scientific view that infectious diseases were preventable, such as Louis Pasteur (a 19th-century French microbiologist and one of the founders of microbiology) and other scientists, and proposed a toxic idea that people with infectious diseases have to blame only themselves.
The reality of the pandemic is that while the death rate is higher among the poor and immigrants, no one is immune to the flu. In other words, when the plague comes, it makes no sense to isolate individual patients or to hold them personally responsible. Epidemic epidemics are problems that need to be solved by the general mobilization of the whole people.
Since the 2020s, the shift in perception of influenza has been reflected in changes in public health policy. Many countries have established or reorganized ministries of health, established more advanced disease surveillance systems, and embraced the concept of socialized care, i.e. universal health care, free medical care.
The pandemic has also changed other aspects of society
The "lost generation" refers to the living generation of the early 20th century, including famous American artists who came of age during World War I, and British officers who died in battle.
The characteristics of the 1918 pandemic and the level of science at the time meant that it was impossible to determine the number of the three lost generations, but we can be sure that each category outnumbered the artists of the Jazz Age and more than the 35,000 British officers who died in World War I (South Africa alone is estimated to have 500,000 "flu orphans").
Those whose mothers are infected during a flu pandemic but are able to get away with it have flu trauma that lasts a lifetime. Studies have shown that they are less likely to go to college, receive less pay, and are more likely to go to jail than their uninfected peers.
There is even evidence that the 1918 pandemic contributed to the baby boom in the 20s, because although the population declined, those who survived were in better shape and capable of having children.
Needless to say, the 1918 pandemic cast a long shadow over the 20th century. We should keep this in mind as we prepare for another flu strike.