From smallpox to coronavirus, we review the vaccines that have changed the course of the most devastating outbreaks in history.
Since the beginning of 2020, the year that brought with it the pandemic that has transformed our world, science has worked against the clock in the research of the vaccine against COVID-19. After a few months of falling incidence largely thanks to the global vaccination of more than 8,470 million doses, at the end of 2021 today the pandemic has resumed the volatility of its figures because of the last omicron variant, less aggressive in its symptoms but strongly contagious. But early analyses of this new variant continue to point to vaccines making a difference, and it’s not the first time in history that inoculations are the key health weapon to fight an epidemic.
Since it was declared a global pandemic by the World Health Organization, the coronavirus figures have continued their ascent, transforming the reality of all countries to the last detail of our day-to-day. Since the arrival of COVID-19, cases exceed 272 million globally. Although obtaining the real number of deaths is difficult, worldwide they exceed 5.3 million, according to data from the Ministry of Health and Our World in data. When analyzing the data of this pandemic through a global prism, the figures are still far from their most lethal competitors in history, but due to the current globalization and the circumstances in which COVID-19 has developed, these two years have given great prominence in our days to the vital importance of vaccines.
In the last century, humanity still lived regularly with various epidemics threatening the entire world with outbreaks of measles, smallpox, typhus, or yellow fever. Until vaccination came. But what was its origin and what have been the most important vaccines throughout history?
Over the past two centuries, its use has saved billions of lives across the planet and curbed devastating diseases around the world. However, historical amnesia makes us easily forget what the world was like before vaccines and there are many who raise their voices against inoculations, for religious, political reasons, or distorted beliefs. Paradoxically, vaccines save us from diseases and in turn, make us forget the diseases from which they have saved us when the threat disappears.
To find the origin of this scientific technique we must go back to the fight against smallpox in China. “Several sixteenth-century accounts describe inoculation against smallpox and note that, in the late seventeenth century, Emperor K’ang Hsi, who had survived smallpox as a child, had his children vaccinated,” the data from the College of Physicians of Philadelphia state.
Doctors developed a technique called variolization,which involved spraying the skin of a person with symptoms to breathe it into the airway of a person than the airways of healthy people in order to immunize them. This technique spread throughout the world until the arrival of the discovery of the vaccines themselves. “It is difficult to pinpoint when the practice began, as some sources claim that they date back to 200 B.C.”
Smallpox vaccine (1796)
“Chinese medicine and its ancestral culture seem to have the most remote antecedents of attempts to prevent or cure the epidemiological scourge of that time: smallpox,” states the study The Origins of the Vaccine,published in the medical journal El Servier. “This empirical knowledge reached Central Asia and Europe, and some farmers made observations of the usefulness of inoculation or variolization without documenting their trials in the scientific community.”
It was not until 1798 that surgeon Edward Anthony Jenner (1749-1823), known as the father of vaccination, revolutionized the fight against smallpox. Jenner’s approach was that if a person becomes infected with a harmless viral load, they acquire immunity to a similar pathogen. At that time he used the cowpox virus to protect from human smallpox.
On July 1, 1796, Jenner infected an eight-year-old boy with the smallpox virus, just weeks after administering the cowpox virus, demonstrating his immunity to a virus that for centuries had been a major threat.
“Smallpox was a highly prevalent disease, causing a major epidemiological problem, distributed almost worldwide, which did not distinguish ages or social classes, and also caused high mortality – from 30 to 60 percent in the unvaccinated – and produced significant sequelae.”
Among the many affected by this disease are pharaohs of Egypt, as certified by their mummies, Elizabeth I of England, classical musicians such as Mozart and Beethoven, and presidents of the United States such as Lincoln and Washington or King Louis I of Spain.
Rabies Vaccine (1885)
In the late nineteenth century, the French bacteriologist Louis Pasteur revolutionized the world of medicine again by discovering the rabies vaccine from an attenuated strain of the virus. This viral zoonotic disease has a lethality close to 100% and is caused through a virus that infects animals and insects and attacks the central nervous system causing acute encephalitis.
Spread throughout history throughout the planet this virus attacks domestic and wild mammals including humans is found in the saliva of infected animals and is inoculated to humans when they cause a bite injury or there is contact with salivary secretions.
The World Health Organization handles data that affirm that in some regions this disease is still a public health problem such as Asia or Africa where it causes more than 55,000 deaths a year most of them under 15 years of age.
Vaccine against tetanus (1890) and yellow fever (1937)
In 1890, Emil von Behring – called the savior of soldiers and children – discovered, in animal studies, that it was possible to produce immunity against tetanus, a disease of the nervous system, by injecting graduated doses of serum from another animal carrying the disease.
At the beginning of World War I, soldiers began to receive small doses of the serum, as it had not been previously tested on humans. In 1914 they managed to get the Administration to distribute it in greater quantities to avoid a greater number of deaths. For his studies in this field and that of diphtheria, Behring was awarded the first Nobel Prize in Medicine.
For its part, yellow fever has been the cause of devastating epidemics and pandemics throughout history, such as the one that affected Barcelona in 1821. The disease was endemic to Africa until the transit of African slaves in the fifteenth century distributed it to the American continent, where the lack of immunity to it caused a highly lethal pandemic that affected European settlers in Africa and America.
The World Health Organization included in the list of allowed drugs the yellow fever vaccine in 1938, after more than five centuries causing deadly epidemics on the planet. To this day, there are still 200,000 cases and nearly 30,000 deaths each year.
This vaccine was born thanks to the South African scientist Max Thyler, who following the line of a previous investigation of the attenuated strain, managed to vaccinate more than one million people. For this, Theiler was awarded the Nobel Prize in Medicine in 1951.
After the British Almroth Edward White developed the typhus vaccine, in the late nineteenth century, the 1920s saw the birth of vaccines against tuberculosis, diphtheria, tetanus and pertussis.
In April 1957, a mysterious illness was advancing through Hong Kong. The American virologist Maurice Hilleman, who had been born in August 1919, in the midst of the Spanish flu pandemic, recognized the threat and began working on a vaccine that stopped the disease when it arrived in the United States, saving millions of lives.
Hilleman studied flu outbreaks and respiratory illnesses at the Walter Reed Institute for Military Medical Research in Washington, D.C. There he showed that flu viruses suffered mutations that allow them to bypass previously developed antibodies, which explained why a single vaccine did not protect for life, as was the case with smallpox or polio.
“In 1957 we overlooked it. The military overlooked it and so did the World Health Organization,” Hilleman said later in an interview.
In total, the virus killed 1.1 million people worldwide. By the time he arrived in the United States, the virologist had already created 40 million doses. “It’s the only time a pandemic has been averted with a vaccine,” Hilleman recalled.
Polio, measles, rubella and mumps (1960s)
Although polio is estimated to have affected human populations for thousands of years, by the end of the nineteenth century, the disease reached epidemic proportions that still severely affect Asia and, until recently, Africa, where it was settled in August 2020.
In Spain, between 1959 and 1963, the inactivated polio vaccine was used, which was administered free of charge to those who did not have resources, although coverage was low, since the number of vaccines available was scarce. In 1965 a new massive campaign was initiated and at the same time vaccination against diphtheria, tetanus and pertussis was added. The success of these interventions determined that, from this moment on, they were carried out continuously.
Three other infections that have caused and continue to cause thousands of deaths are measles, rubella and mumps. Already in the twentieth century, during the 1960s, Hilleman created in 1967 a vaccine for mumps, in 69 for rubella and two years later a combined vaccine that would provide immunity for the three viruses, commonly known as tripleviral.
Researchers at pharmaceutical company Merck, under the direction of Maurice Hilleman, detected an ape virus in monkey kidney cells used to grow poliovirus for Merck’s polio vaccine. Hilleman later showed that the ape virus, SV40, caused tumors in hamsters.
Merck eventually recalled its polio vaccine. In 1963, government screening programs began looking for ape viruses in poliovirus vaccines. Hilleman was also behind vaccines, in the 1970s, for chickenpox, pneumococcus and meningitis.
Subsequently, although there was an epidemic of a type of flu very similar to the flu of 1918, it did not have much expansion. The next vaccine with the greatest global impact, therefore, is that of the coronavirus. Its brutal immediate impact on the entire world due to globalization, led all international laboratories to try to find the vaccine as soon as possible.
To this day, there are still many infectious diseases that cause millions of deaths a year, especially conditions such as HIV and tuberculosis that do not yet have a vaccine. Another of the great global health concerns, malaria, has lived in October 2021 a “historic moment” with the approval of the first vaccine against this disease. In addition, according to the United Nations Environment Programme (UNEP), climate change and the loss of biodiversity are factors that multiply the risk of suffering new pandemics in the future.