Humanity has come a long way. For thousands of years, from prehistoric times to the industrial age, life expectancy was only 25-30 years because infant mortality was so high – half of all children were likely to die before the age of 10. Add to this the triad of violence, malnutrition, and infection. Insecurity about health was palpable.
From 1750, improving health care was off to a difficult start. Inequalities were high and became even greater with industrialization and urbanization. For example, cities became densely built up and poisoned by coal works – a phenomenon that occurred particularly in England. Working conditions for the poorest were hard and degrading, both physically and psychologically. Only the richest could be healthy.
But since then, life expectancy has almost tripled in just three centuries thanks to unprecedented medical, industrial, and economic revolutions. These advances, however, are now threatened by two types of risk. The first types are environmental risks (pollution, heat waves, and zoonoses). The second types are behavioral risks, such as smoking, alcohol consumption, physical inactivity, and obesity. This time it seems that everything that was missing earlier has become excessive.
The first attempts at voluntary immunization began in the 18th century with Variolation. This technique was used to combat smallpox, which at the time killed 20-30% of those infected. Long denounced, it consisted of exposing a person to a pustule of a patient who was not suffering from a severe form of the disease.
Although Edward Jenner carried out the first vaccine trials in 1796, Louis Pasteur’s discovery of the microbe was the most important event. The microbial theory is one of the most important facts in the history of medicine and public health, and probably in history which gradually replaced the miasma theory and was established in the 1870s, leading to the mass development of vaccines fifteen years later. During the same period, the surgeon Joseph Lister introduced antisepsis during his operations. A method of preventing and fighting infections by destroying microbes. He used phenol to disinfect hands and sterilize instruments, which led to a threefold decrease in postoperative mortality.
Much later, after the First World War, healthcare entered a new phase. Advances in science and health systems, such as social security, benefited the whole population. Also, medicines such as antibiotics, anti-inflammatory drugs, anxiolytics, and blood pressure-lowering drugs were introduced. Surgery would become more complex, such as coronary bypass grafting – a pioneering surgical innovation to revascularize the heart. Certain chemotherapeutic drugs start to become effective. Everything was moving fast.
Indeed, the linear increase in life expectancy is mainly the result of public health measures that have helped to clean up cities, through waste management, the provision of drinking water, and better nutrition. But also thanks to the intensification of information campaigns.
A century of decline
In the 21st century, the world is getting older, but not healthier. Mortality has increased in some rich countries and life expectancy has decreased. New problems are emerging, such as chronic diseases and certain types of cancer, whose incidence is increasing. The latter has become the leading cause of death in high-income countries – overtaking cardiovascular disease. At the same time, other older problems such as infectious diseases, of which Covid-19 is just one example, are re-emerging.
These new risks are mainly caused by avoidable human actions and catastrophic environmental change. For example, access to water is becoming problematic in countries experiencing droughts, the air in major cities has become unbreathable and the nutritional value of food has deteriorated over years of intensive agriculture.
Despite these worrying issues, the Covid-19 pandemic has shown that people are resilient and can suddenly adapt even when their complex systems are not working properly. Now it is a question of whether humans will learn from their mistakes only time will tell.
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