Spanish Flu

                  SPANISH FLU (1918-1920)

In many ways, it is hard for modern people living in First World countries to conceive of a pandemic sweeping around the world and killing millions of people, and it is even harder to believe that something as common as influenza could cause such widespread illness and death. - Charles river editors

The 1918 influenza pandemic was the most severe pandemic of the last century. It was caused by an H1N1 virus with genes of avian origin. It is estimated that about 500 million people, or one-third of the world’s population, became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide. Mortality was high in people younger than 5 years old, 20-40 years old, and 65 years and older, which was a unique feature of this pandemic.

The pandemic occurred in three waves. The first apparently originated in early March 1918, during World War I. Although it remains uncertain where the virus first emerged, it quickly spread through western Europe, and by July it had spread to Poland. The first wave of influenza was comparatively mild. However, during the summer a more lethal type of disease was recognized, and this form fully emerged in August 1918. Pneumonia often developed quickly, with death usually coming two days after the first indications of the flu. The third wave of the pandemic occurred in the following winter, and with the advent of spring, the virus had run its course.

India is believed to have suffered at least 12.5 million deaths during the pandemic. Other outbreaks of Spanish influenza occurred in the 1920s but with declining virulence.

While the 1918 H1N1 virus has been synthesized and evaluated, the properties that made it so devastating are not well understood. With no vaccine to protect against influenza infection and no antibiotics to treat secondary bacterial infections, control efforts worldwide were limited to unevenly applied non-pharmaceutical interventions such as isolation, quarantine, good personal hygiene, use of disinfectants, and limitations of public gatherings.

No specific anti-viral therapies were available during the 1918 flu. That’s still largely true today, where most medical care for the flu aims to support patients, rather than cure them. Exposure to prior strains of the flu may have offered some protection, considering that soldiers who had served in the military for years suffered lower rates of death than new recruits.

In addition, the rapidly mutating virus likely evolved over time into less lethal strains. This is predicted by models of natural selection. Because highly lethal strains kill their host rapidly, they cannot spread as easily as less lethal strains.

Severe influenza epidemics tend to occur every few decades. Experts believe that the next one is a question not of “if” but “when.” 

While few living people can recall the great flu pandemic of 1918, we can continue to learn its lessons, which range from the importance of handwashing and immunizations to the potential of anti-viral drugs. Today we know more about isolation and handling of the sick. Perhaps the best hope lies in improving nutrition, sanitation and standards of living, which would render humans more resistant to infection.

For the foreseeable future, flu epidemics will remain a looming threat over humanity. As a society, we can only hope that we have learnt our lesson from the great pandemic, in order to quell another such worldwide catastrophe.