Over 140,000 Luxembourgers have received at least the first dose of the Covid-19 vaccine, and the vaccination rollout in Europe is steadily moving us closer to the end of the tunnel.

What took less than a year to develop (at record speed, the mumps vaccine took about four years) is the result of centuries of scientific development against infectious disease – starting in fifteenth-century China.

While reading up about the history of vaccines, I stumbled upon excerpts of a Chinese encyclopaedia dated from the early eighteenth century – depicting smallpox and methods to fight it. Turns out the Chinese knew the disease well before it found its way into Europe, as the Qing emperors commissioned a group of doctors to compile extensive texts on Chinese medical knowledge. The illustrations suggest that Chinese doctors had fought the disease by preserving scabs from mild infections and turning them into a powder-like substance that would be inserted up the nostrils.

Inoculation, the term used to describe methods for artificially induced immunity against diseases, was thus well established and understood by the time it was introduced in Europe. Except that these ancient methods of Qing China, Africa, and India were predecessors and were known as variolation (variola meaning smallpox), but that is not the point. The point is that immunity techniques against infectious disease can be traced much further than back to Edward Jenner, the English physician that performed variolation in the late 18th century. Evidence of smallpox can even be found as far back as the eleventh century, but the written records do not mention how the disease was treated, if at all.

Let’s shift our focus onto eighteenth-century Western Europe and Edward Jenner’s work in developing a reliable inoculation technique against smallpox. In 1796, he tested a common belief that milkmaids were immune from smallpox due to their exposure to cowpox, a disease that only resulted in mild symptoms in humans, but seemed to create immunity against the human disease. Jenner used inoculation by collecting pus from a cowpox blister, which he then scratched into an eight-year old’s arm before infecting him with smallpox. The boy did not contract the virus, confirming Jenner’s hypotheses which he further elaborated in his book An Inquiry into the Causes and Effects of the Variolae Vaccinae. This is also where the name vaccine came from, derived from the Latin word for cow, vacca.

What was initially deemed a great success in the medical world soon found its limits, as human diseases do not always have an animal form which could bring about immunity. Nineteenth-century scientists quickly established that they needed to weaken the virus while upholding its physical conditions intact so that the immune system could recognise the foreign body in an eventual infection.

This is where French biologist Louis Pasteur comes in. His experimental work laid the foundations of the modern vaccination principles, which were reflected in his successful development of anthrax and rabies vaccines. Pasteur managed to introduce weaker forms of the viruses into people’s immune systems, resulting in the production of antibodies which in turn built up immunity in case of a real infection. In honour of Edward Jenner, Pasteur named the process vaccination. With this principle in mind, vaccinations replaced inoculation practices in Europe during the 1850s – with mandatory smallpox vaccination policies being drafted in Sweden, Prussia, and England among others – regardless of the population’s safety concerns. That’s right, anti-vaccination campaigns have existed as long as vaccination has.

When the government launched a series of laws that made smallpox vaccinations compulsory, riots broke out across England to protest the government interference. Other reasons for protest were safety concerns and religious beliefs that inserting substances from ‘lowlier creatures’ into the human body was ungodly. This anti-vaccination campaign was especially prominent in Leicester, where an Anti-Vaccination League was created in 1869. Debates about citizen’s freedoms and rights became especially prevalent, as did questioning the qualifications of medical practitioners. Despite government efforts to fine and prosecute anti-vaccination campaigners, much of Victorian society would continue to resist the public health policies in favour of personal freedom. To this day, vaccine hesitancy is deemed one of the biggest threats to global health by the World Health Organisation.

A century later, the WHO launched a global vaccination campaign against smallpox – with improved and more reliable vaccines – which resulted in the complete eradication of the disease by 1980. In the twenty-first century, vaccinations take on a new form as scientists can now rely on RNA or DNA strands that are introduced to the immune system to sensitise it to the pathogen. The Covid-19 vaccine was developed on such principles, and many other vaccines will be as well as new viruses will continue to materialise.

Images mentioned throughout the article linked below.