Vaccines: a great human conquest

It was 1796 when Edward Jenner opened a new page in human history by laying the foundations of modern immunisation and successfully developing a vaccine against smallpox. This disfiguring infectious disease with high mortality (>30%, higher in children), left survivors marked for life with terrible scars. The development of the first vaccine was followed by several others (tetanus, whooping cough, tuberculosis, polio, to cite a few), leading to a remarkable decrease of reported cases of common diseases in children and so saving the lives of millions. In 1956, the WHO started a global vaccination campaign to eradicate smallpox from the world; it took 24 years (until 1980) to succeed. Vaccines are now considered one of the greatest medical achievements in modern civilization.


Fig. 1: Comparison of 20th Century Annual Morbidity and 2010 Morbidity for Vaccine-Preventable Diseases in the United States: 20th century (JAMA 2007, 298(18): 2155-2163) – 2010 (CDC. MMWR January 7, 2011; 59(52);1704-1716)

Despite these tremendous results, there has also been quite a lot of controversy around vaccinations, mainly regarding efficacy and safety. These days, driven by widespread use of the internet and the advent of social media, several anti-vaccination campaigns have been launched and are becoming more and more popular. Surfing the web, it is possible to find all sort of contradicting and confusing information about vaccines and how harmful they can be. Once news has spread, it is very difficult to retract and requires quite a lot of work to establish what is real and what is not. Everyone has the right to gather information and have their own opinion with regards to vaccination, but as the real efficacy and safety of vaccines can be questioned, the opposite should also be taken into consideration and should be evaluated very cautiously (see “Six common misconceptions about immunization”).

One of the most controversial of these campaigns was the publication of a research paper in 1998 in which a link was reported between measles-mumps-rubella (MMR) vaccine and the development of autism in children. Following the publication of the paper, multiple large epidemiological studies were undertaken establishing that there was no link between MMR-vaccine and autism. The original paper was subsequently retracted by the publishing journal. Despite all the evidence, people continue to doubt the safety and efficacy of vaccines, opting out from vaccinating their children. The drop in the number of vaccinations has caused outbreaks of diseases that were previously very well contained, as to be effective at least 95% of the population needs to be vaccinated. One of the most recent is the spread of measles across Europe (> 500 cases reported in January 2017) and US (61 cases in the first quarter of 2017), where it was eliminated in 2000. In a world facing a post-antibiotic era and the increasing instances of cancer amongst several other diseases, there is no space to worry about life-threatening diseases that have been already defeated.

Blog written by Marco Derudas 





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