The distrust of vaccines and the total rejection of a part of the population to be vaccinated are phenomena that appeared when this technique was invented, at the end of the 18th century.

Protecting people from diseases will not cease to be a priority action, scientific innovation has the possibility of saving thousands of lives as is happening in the world with the vaccine for COVID-19. Currently, scientists have managed to develop a technology that extracts the RNA or DNA of pathogens to inject them into the human body, so these pieces of genetic material will make human cells produce proteins to educate the immune system. This is the first time that a vaccine with this technology has been used.

However, the anti-vaccines persist with a series of arguments that completely lack scientific evidence, but that generate serious doubts in the world population.

The world's misinformation and skepticism about vaccines have always influenced people's attitudes, beliefs and behaviors towards vaccination campaigns.

Smallpox, the only human disease that has been eradicated

Smallpox was for many centuries a terrible disease, causing the death of 60 million people in Europe in the 18th century. And in the 20th century, it wiped out some 300 million people worldwide.

In 1796, the English physician Edward Jenner had the idea of ​​inoculating a child with a form of the mild smallpox virus to stimulate the child's immune response. He discovered that if he took an extract from a cowpox sore and injected it into a human being, that person was protected against the disease. The process worked, but mistrust and fear quickly arose on the part of the population, who believed that introducing an animal product into a human body was an abomination, the animalization of the human being.

In the UK, smallpox vaccination was made compulsory for children from 1853, in a series of laws that fined parents who refused to vaccinate their children. Over the years, millions of people were saved from dying thanks to the creation of this vaccine, until the worldwide eradication of the disease by 1980.

Louis Pasteur one of the most important scientists of the 19th century

In 1885, Louis Pasteur developed a vaccine against rabies from an attenuated strain of the virus. He performed a successful injection on Joseph Meister, a boy who had been bitten by a dog suspected of having rabies. In this case there was also mistrust. Pasteur was accused of wanting to enrich himself by manufacturing "laboratory rabies".

Then, writes Pasteur, "I decided, not without living and painful anguish, as may well be supposed, to try on J. Meister the method which had consistently given me good results with dogs." The rest is history, weeks later other people bitten by rabid animals were treated with Pasteur's method and protected from the cruel disease.

BCG (Bacillus Calmette-Guérin): an example of patience and thoroughness

In 1921, a newborn baby in Paris received the first dose of a pioneering tuberculosis vaccine. Getting to that point had taken years of sacrifice for the two French scientists who developed the vaccine, Albert Calmette and Camille Guérin.

In 1882 the German microbiologist Robert Koch had discovered that the tubercle bacillus (Mycobacterium tuberculosis) was the causal agent of it. In 1906, the veterinarian and immunologist Camille Guérin had established that immunity against tuberculosis was related to the presence of the bacillus in the blood. Using Pasteur's method, Calmette investigated how he could develop an attenuated variant of the bacillus that he could inject into animals. From 1908 to 1921, Guérin and Calmette strove to produce less and less virulent strains of the bacillus. The lab work they did is an example of the patience and thoroughness that characterize lab life.

However, when aluminum salts began to be used as an adjuvant to increase the efficacy of vaccines, they came under heavy criticism from opponents of vaccination, particularly in France.

A century later - being the oldest vaccine in use called BCG (or Bacillus Calmette-Guérin) - it is still the only one that exists against tuberculosis, a disease that kills more than 1.4 million people in the world every year .

SALK - SABIN the heroes of polio eradication

Jonas Edward Salk was an American physician and virologist recognized for his discovery and development of the first safe and effective polio vaccine in 1955. When asked in a television interview who owned the patent on the vaccine, Salk replied: “There is no patent. Can the sun be patented?

For his part, Albert Bruce Sabin revolutionized medicine at the end of the decade in 1950 when the oral polio vaccine was discovered. Jonas Edward Salk had invented a vaccine against all three types of poliovirus; but he had the drawback that it was intramuscular. Sabin developed an oral vaccine that was given to children in a sugar cube.

Today, the oral Sabin vaccine - which began to be used in 1957 - is used throughout the world and saves millions of lives. However, in many areas of Asia even today this disease causes paralysis in the smallest. The failure of the vaccination campaigns is explained above all by the mistrust of the rural populations and the belief in plot theories against the Muslims.

2009 and the failure of the H1N1 vaccination

In 2009, the H1N1 flu pandemic sounded alerts at the WHO. Vaccination campaigns were organized but the epidemic was less serious than expected, since it did not quarantine entire cities or nations.

Millions of doses had to be destroyed and criticism of mismanagement reinforced mistrust in vaccines in many countries, where "anti-vaccines" highlight cases of side effects. For those years, the scientific community assured that the vaccine generates antibodies; but just as there is no evidence that it causes collateral damage, there is also no evidence that it is frankly necessary in the face of a disease whose risks are not proven.

"Vaccination refusal is as old as vaccination itself," according to health historian Patrick Zylberman. Now that feeling is back in the news with COVID-19 because the authorities are pressing for the maximum population to be inoculated.