The Deadliest Pandemics of the 20th Century

Viral outbreaks are common, but they rarely reach pandemic level. A virus becomes a pandemic when it spreads across the world — just like what's happened with COVID-19. Let's take a look at some of the worst pandemics of the last century and see if there's anything we can learn about how COVID-19 might play out.

Spanish Flu (1918 – 1919)

The deadliest pandemic of the 20th century, the Spanish flu killed more than 50 million people around the world. In fact, more people died from Spanish flu than during World War I. What's unusual about the Spanish flu is the number of healthy young people who died from it.

It's unclear what exactly caused the Spanish flu or where it came from, but scientists believe that an H1N1 virus was responsible. We know that it hit hard because it was a new virus against which people had no natural immunity — just like COVID-19.

HIV/AIDS (1981 – Present)

Scientists first discovered human immunodeficiency virus (HIV) in the 1980s, and this global killer remains lethal to this day. It's thought that HIV emerged from a chimpanzee virus in Africa in the 1920s, and since then, HIV and acquired immunodeficiency syndrome (AIDS) have killed more than 25 million people around the globe.

The good news is that HIV is treatable now with antiretroviral medications, which stop the virus from multiplying. However, it's still a pandemic, because it affects people in every country of the world.

Asian Flu (1957 – 1958)

First identified in East Asia in February 1957, the Asian flu killed over 1.1 million people worldwide. Although most people experienced mild illness, the reported symptoms were very specific — wobbly legs, chills, sore throat and even nosebleeds.

Compared to pandemics like the Spanish flu, the death toll was fairly low, but it's only because scientists identified the unique nature of the virus quickly and made a vaccine available by August 1957.

Hong Kong Flu (1968 – 1970)

Only 10 years after the Asian flu, the Hong Kong flu arrived. The virus bore hallmarks of the H2N2 virus that caused the earlier pandemic, and it was first discovered in China in mid-1968.

The Hong Kong flu killed around 1 million people, and it's one of the most contagious viruses on this list — within two weeks of its identification, it had already infected over 500,000 people across the region.

Russian Flu (1889 – 1890)

Believed to be of avian origin, this H2N2 virus killed around 1 million people. It was first discovered in late 1889, and finally hit pandemic status in late 1890 when it reached Asian shores.

The Russian flu was one of the first widely reported pandemics; nevertheless, we still know very little about it. What we do know is that it spread relatively easily across continents on ships and trains.

COVID-19 — the 21st Century Pandemic?

It was only a matter of when — not if — the next pandemic arrived. Scientists first identified the novel coronavirus in Wuhan, China, in late 2019, and it's thought that the virus came from bats.

What's alarming is how similar it is to the Spanish flu — we have no immunity, and it's spreading at an unprecedented rate. So far, there have been well over 92,000 deaths, and although it's too early to tell what trajectory the virus will take, it's set to become a pandemic for the history books.

Take Home Message

The good news is that no pandemic lasts forever, even COVID-19. The National Health Service recommendsregularly washing or sanitising your hands to protect yourself against most viral threats — check out Your Sanitiser to keep your hands safe.