Smallpox: The Death of a Disease – The inside story of Eradicating a Worldwide Killer

​D. A. Henderson
New York, Prometheus Books, 2009
334 pp., Hardcover
27.99 $ USD
ISBN 978-1-59102-722-5

 Smallpox: The Death of a Disease was written by Dr. Henderson, the director of the World Health Organization (WHO) Smallpox Global Eradication Unit and a key expert in Public Health.
              The narrative starts with a historical background of this deadly disease and its main characteristics. Then, the difficulties of convincing leaders in relevant political positions, including the Director-General of WHO, that smallpox could be eradicated are described. One sentence I found particularly striking was: “Not surprisingly, the debate as to whether or not to pursue smallpox eradication came down primarily to a question of money”.
              In chapter 3, the author presents one important discovery, that took place in 1965: the bifurcated needle, which made possible to get 100 vaccinations out of a vial vaccine, instead of only 25 vaccinations.
              In the following chapters, Dr. Henderson describes in detail the adversities that he and his local teams had to face in Africa and in Asia. Those difficulties included social, geographic, and political problems, such as densely populated areas, migrations, droughts, and false data (“…soon it became apparent that reports of known cases were being suppressed.”).
              In chapter 8, he describes the last case of smallpox, in 1977, in Merca, Somalia. Two years later, smallpox was considered officially eradicated. In the 33rd World Health Assembly (8th May 1980), the final report stated: “ … calls this unprecedented achievement in the history of public health to the attention of all nations, which by their collective action have freed mankind of this ancient scourge and, in so doing, have demonstrated how nations working together in a common cause may further human progress.”
              Finally, D.A. Henderson concludes with “Lessons and Legacies of Smallpox Eradication”, as a “… demonstration of how much could be accomplished with how little in the control of infectious diseases through community-wide vaccination programs.”.


Smallpox vs. COVID-19 – The story of (trying) to Eradicate a Worldwide Killer (again):
              At the present, we are facing again a global pandemic, due to a worldwide killer: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

              If we compare COVID-19 with smallpox, there are several similarities such as:

• Both viruses emerged in centers of urban civilizations: SARS-CoV-2 in Wuhan, China and the latter in Egypt and Southern Asia.
• Transmission of both diseases is similar: the spread of the virus happens when the infected person coughs or sneezes, and droplets from their nose or mouth are spread to other people. (1)
• Until vaccination was available, there was no effective way to prevent smallpox other than isolating patients and quarantining who might have been exposed, which is exactly what happens nowadays with COVID-19.
• With regard to smallpox, elaborate measures were taken to ensure that every house with a confirmed case would have 24 hours guards to make sure that the patients would not leave the house. Nowadays, in Portugal and in another countries, police authorities receive a list with the names of people under active surveillance (people with COVID-19 and their high-risk contacts).

 
              However, there are also differences, some of which make the SARS-CoV-2 virus more difficult to eliminate (or even eradicate) than the smallpox virus, as listed below: 

• Smallpox virus only infected humans, there was no reservoir in nature, as opposed to SARS-CoV-2 that can also infect animals.
• Smallpox was a symptomatic disease – each infected person exhibited a rash that could easily be identified. On the contrary, COVID-19 may be associated either with symptomatic and asymptomatic confirmed cases. (2)
• In the case of smallpox, all who recovered were immune for life. On the other hand, since COVID-19 is a novel disease, immunity for life remains to be proven.

 
              Important lessons from the eradication of smallpox should be taken and applied to the current SARS-CoV-2 pandemic. Public Health professionals’ effort is key to the control of this pandemic: “The triumph belongs to an exceptional group of national workers and to a dedicated international staff from countries around the world who have shared privations and problems in pursuit of the common goal.”
 

Autoria Filipa Malcata
Edição Filipa Gomes


References:
1. Centers for Disease Control and Prevention. Transmission | Smallpox | CDC [Internet]. Cdc.gov. 2016. Available from: https://www.cdc.gov/smallpox/transmission/index.html
2. European Centre for Disease Prevention and Control. Transmission of COVID-19 [Internet]. 2020. Available from: https://www.ecdc.europa.eu/en/covid-19/latest-evidence/transmission