The 1918 pandemic in Salamanca, a forgotten lesson

Section: Editorial


Dr. Juan Fernández Dolón


Enfermero. Unidad de Cuidados Intensivos. Hospital Comarcal de Inca (Illes Balears).Facultad de Ciencias de la Salud. Universidad Pontificia de Salamanca.

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The wrongly called Spanish influenza is considered one of the worst healthcare catastrophes in the 20th century. It was caused by a serological regrouping with avian origin of the H1N1 subtype, and according to the latest estimations, it caused an impact on mortality of 50 million persons (around 3-6% of the world population). Although there is no universal consensus about the place where the virus originated, the fact is that it spread throughout the world during 1918 and 1919 (1,2).

To really know what happened remains a question today for public health and epidemiology, but it is possible to determine the three factors, which led to a higher severity of the pandemic. Firstly, social factors such as the spread of the virus facilitated by the transit of persons / soldiers during the First World War, a non-existent network of Public Health and healthcare systems, as well as the lack of development of vaccines and effective treatments for infection (3,4) . Secondly, there were virulence factors which had an impact on the severity of the pandemic upon young population groups (2,5). And finally, population factors such as the level of protection, geographical isolation, and immunological boost (3,4).

In Spain, the influenza epidemic became a threat and a challenge for the health and government authorities of the time, when faced with an unknown event which caused high mortality, and in a complex social setting with very strong socioeconomic inequalities.

Among many others, Salamanca was a Spanish city with one of the highest mortality rates, exacerbated by the influenza epidemic. In 1918, the capital city suffered the consequences of a life which bordered misery and need, and compromised the health conditions and hygiene of the population (6). Despite the attempts by authorities to improve hygiene, the city continued experiencing weaknesses in services such as water supply, street cleaning, sanitation, and sewage. These factors would not only encourage the development of infectious and epidemic diseases (cholera or typhus), but also the presence of other diseases and associated complications (respiratory, cardiovascular, and gastrointestinal).  

Knowing in advance all this background, and with the aim of assessing the impact of the epidemic in Salamanca, as there were no previous studies, given that there was only previous research on the impact of the 1918 pandemic in Salamanca (7), a topographic study of mortality by neighborhoods and periods from 1917 to 1919 was carried out, in order to analyze the demographic repercussions (8).

For this aim, on one hand there was a documentation analysis of written sources of the time. The main contributions were primary bibliographical sources, such as press articles, the municipal register, and other public administration records (city and provincial councils), which referred to the epidemic and addressed matters regarding the origin of the disease, its potential vector for entering the city, diagnosis, urban demographical impact, social impact, and preventive and therapeutic measures taken against the infection (8).

On the other hand, a mortality analysis was conducted (descriptive and inferential). A statistical analysis was conducted on the resident population deceased in the city in 1917, 1918 and 1919, according to the data collected in the death records from the Diocesan Archive and the Civil Registry of Salamanca. In this sense, the initial hypothesis for the study was that the influenza epidemic had different impact on mortality based on different sociodemographic variables. For this, there was a review of mortality caused by diseases in the different districts and sections, analyzing the differences between the causes of death, and researching whether there was an association of risk of death by cause of influenza based on different sociodemographic variables (gender, marital status, etc.) (8).

With this methodology established, very conclusive results were obtained, which showed the association of risk with sociodemographic variables such as marital status (single and married), on the 3rd and 4th quarter of 1918 (coinciding with the 2nd epidemic wave), as well as the younger population groups, as those factors associated with a higher risk of death by influenza. At the same time, it was confirmed that an excess mortality by all causes of death was registered in 1918; this increase in the series of deaths was attributed to the epidemic, coinciding with the months of September and October (8).

Currently the story is repeating itself, one hundred years afterwards, and without having learned anything. Many of us are looking at the 1918 epidemic in order to understand the current SARS-CoV-2 pandemic. As Aldous Huxley said: “That human beings do not learn very much from the lessons of history is the most important of all the lessons of history”. 

Both pandemics present differences and similar patterns. The 1918 epidemic was not linked to any disease determined by science and Medicine. The epidemic had a high mortality impact on young population groups, while the current pandemic causes higher mortality in >80-year-old persons. However, after one hundred years, we are living in a pandemic and facing the most direct consequences (demographical, social, and economic) of a fact that seemed to have faded in the past. The influenza virus evolved phylogenetically, developing new serological subtypes which have created pandemic strains throughout history (after 1918, those in 1957, 1968 and 2009).

Just like the Spanish influenza, the SARS-CoV-2 pandemic will finally be over; but there will always be epidemics, viruses will keep evolving, and therefore, we must create awareness for this challenge. With this mortality study based on an interdisciplinary setting (from a social, human, and scientific perspective), we can realize that the worst epidemics are not biological but moral.  

Regardless of the scientific advances to fight against infectious diseases, we ignore those behaviours, values and attitudes that define us as a society, rejecting messages by healthcare authorities and thus revealing a collective selfishness against an epidemiological threat.


  1.  Centros para el Control y la Prevención de Enfermedades (CDC). Historia de la pandemia de gripe de 1918. CDC [internet]. 2018. [citado 29 jun 2021]. Disponible en:
  2. Patterson KD, Pyle GF. The geography and mortality of the 1918 influenza pandemic. Bulletin of the history of medicine 1991; 65(1):4-21.
  3. Chowell G, Erkoreka A, Viboud C, Echeverri-Dávila B. Spatial-temporal excess mortality patterns of the 1918-1919 influenza pandemic in Spain. BMC Infectious Diseases. 2014; 14(1):[371].
  4. Ortín J. Cien años de la pandemia gripal de 1918: ¿una historia repetible?. Virología. 2019; 1:5-11.
  5. Ortiz de Lejarazu R. La pandemia de Gripe Española vista desde el siglo XXI. Anales de la Real Academia de Medicina y Cirugía de Valladolid. 2018; 55:367-84.
  6. Rabaté JC. 1900 en Salamanca. 1900 en Salamanca. Guerra y paz en la Salamanca del joven Unamuno. Salamanca: Ediciones Universidad de Salamanca; 1997.
  7. Sena Espinel MP. La pandemia gripal de 1918 en Salamanca y provincia [Tesis doctoral]. Salamanca: Universidad de Salamanca; 1992.
  8. Fernández Dolón J. Estudio de mortalidad de Gripe Española en la ciudad de Salamanca [Tesis doctoral]. Salamanca: Universidad Pontificia de Salamanca; 2020. [citado 29 jun 2021]. Disponible en: