While the world today is shaken by the recent COVID-19 outbreak, history reveals that pandemics are rare, yes, but they do occur periodically. The year 2018 was the 100th anniversary of one of the most devastating outbreaks in centuries, Spanish flu, also known as the mother of all pandemics. 

The last century has also witnessed Asian flu, Hong Kong flu, HIV/AIDS pandemic and each with deadlier effects worldwide. Each pandemic is unique in its way, and so is the aftermath that comes with it. This article discusses the similarities and dissimilarities between Spanish flu and COVID-19 and tries to find a few lessons from history to handle the current pandemic better.

Two World-changing Pandemics

Spanish Flu

The highly contagious Spanish flu was caused by the H1N1 influenza virus that attacks the respiratory system. As one may assume Spain to be the origin of Spanish flu, but interestingly enough, this is not the case.[1] In 2018, the countries involved in the war practiced information censorship to suppress reports on the influenza impact to not appear weakened in the eyes of the enemies. As a neutral country, Spain first reported about the pandemic and hence it was named such.

The war ended and the soldiers returned home carrying the virus with them. The virus reached worldwide, the epidemic turned into a pandemic infecting around 500 million people and killing an estimated 17.5-50 million people.[2]


Most of the symptoms of COVID-19 disease are similar to the Spanish flu as both of the viruses cause respiratory infections. While Spanish flu was estimated to have a reproductive rate (R0) of 1.8, COVID-19 was approximated to have its R0 between 1.4-3.9.[3] Being identified in December 2019 in Wuhan, the disease has spread worldwide only within four months, resulting in the current COVID-19 pandemic. So far, the virus has affected more than 3,000,000 people around the world with the number increasing every day.[4]

Mortality Patterns of Spanish Flu & COVID-19

The Spanish flu pandemic elapsed till 1920 occurring in three waves. The first wave was comparatively mild that started in early March 1918, during World War I. The second wave fully emerged in August 1918 in a more lethal form. In the following winter in 1919, the third wave of the pandemic arrived and at the start of 1920, the virus was gone.

FIGURE: The three waves of Spanish flu pandemic / Source: Centers for Disease Control and Prevention

Based on the world population being 1.8 billion in 1918, even the low estimation of 17.5 million deaths implies that almost 1% (0.95%) of the world population was killed by Spanish flu, making it the deadliest pandemic in history.[2]

The virus also spread in Asia and devastated the poor countries. It eventually reached British India where the severity of the outbreak was denied by the colonial officials and it ended up killing around 18 million people, 6% of India’s population. The renowned anti-colonial nationalist Mohandas K. Gandhi contracted the flu, but luckily survived.[6]

Usually, older populations tend to be most susceptible to respiratory infections which has been the case for ongoing COVID-19. However, going against the norm, Spanish flu killed a large share of the young population. The reason behind older people’s resilience to the Spanish flu was suggested that they had gained some immunity through an earlier outbreak, the Russian flu pandemic of 1889-90.[2]

FIGURE: Spanish flu fatality rate by age / Source: BBC
FIGURE: COVID-19 fatality rate by age / Source: Chinese Centre for Disease Control and Prevention

The figures show that age-specific mortality between Spanish flu and COVID-19 appears to be very different. While the Spanish flu was particularly dangerous to younger people, the COVID-19 seems to be most fatal to the elderly. 

Key Differences Between Spanish Flu & COVID-19

It should be taken into account that Spanish flu is a century-old incident and the overall world scenario has radically changed over the time. COVID-19 will not necessarily turn out as destructive as Spanish flu did. Therefore, while drawing a comparison between Spanish Flu and COVID-19, some differential factors should be noted.

Globalization: Due to high global mobility, the COVID-19 virus could easily spread around almost every corner of the world. Through airlines it took only three months to reach worldwide. On the other hand, it took almost a year for Spanish flu to spread as only railroads and ships used to connect the world.

Health Infrastructure: Most Spanish flu victims were affected by bacterial pneumonia followed by the virus infection. Health technology was at its nascent stage and antibiotics were yet to be invented. The genetic sequence of the Spanish flu virus was only discovered in 2005. 

However, the genome structure of COVID-19 antibiotics has already been discovered and experts are working towards developing the vaccines. Antibiotics are being used to tackle the bacterial infections that come after the virus. There has been immense advancement in medical technology and health infrastructure which increases the chance of tackling the COVID-19 in real-time.

Increased Awareness: During the Spanish flu, many countries tried to hide the information about the outbreak. This resulted in people having little knowledge about the precautionary measures and the severity of it. 

With the wide reach of the internet and social media, the sharing process of data, research, and news has been more open than in the past, leading to increased awareness among the mass. However, censorship in China which led to this global pandemic and data transparency of Taiwan indicates that the transparency in the information reporting system still varies between democratic and authoritarian governments.

Population Profile: The 1918 flu hit a war-torn world, with a large share of the population being poor, undernourished and with poor sanitation systems. However, most of the countries are much richer and much healthier now holding better capacity to deal with a pandemic.

Minimizing Adverse Economic Impact: Lessons From 1918 Outbreak

The key takeaway from the 1918 flu would be the importance of non-pharmaceutical interventions (NPIs) such as social distancing and its impact on reducing economic downturn. The cities in the US that implemented early and extensive social lockdown did not suffer adverse economic effects over the medium term, rather experienced a relative increase in real economic activity after the pandemic receded.[5]

FIGURE: The effect of non-pharmaceutical interventions on mortality rate / Source: World Economic Forum

The figure has splitted the cities into two groups: the blue dots and red dots represent the cities with NPIs in place for longer and shorter periods respectively. Cities with longer NPIs periods appear to be clustered in the upper-left region (low mortality, high growth) whereas cities with shorter NPI periods are clustered in the lower-right region (high mortality, low growth). This suggests social lockdown to be the best remedy for both flattening the curve and minimizing adverse economic impact.

The Ebola outbreak in 2014-2016 in West Africa required similar interventions. The outbreak was controlled by the collaborative efforts of the international organizations which helped the countries limit physical contacts among the mass, educate them about the precautionary measures and build strong hygienic systems. Taking a lesson from this, less developed countries should prioritize educating rural societies about the safety measures with the help of trained health workers to tackle COVID-19.

At this stage, the possibility of COVID-19 reaching close to the Great 1918 Pandemic seems far away given the advances in public health and mitigating policies in place. However, the previous outbreaks retell how large of an impact pandemics can have in the world and therefore, countries should be careful about pursuing their policies to reduce the damage and curb the spread of the disease.

Ishrat Jahan Holy, Trainee Consultant at LightCastle Partners, has prepared the write-up. For further clarifications, contact here: [email protected]

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