While the world is being ravaged by COVID-19 pandemic, this is not the first and by any means the deadliest of the pandemics. Pandemics are part of the human existence from the very beginning, cropping up in some part of the world periodically. Over the past two thousand years, Plague pandemics, caused by bacterium Yersinia-Pestis, spread by fleas living on rats, have killed tens of millions.
If we look at the last hundred years or so, there have been six major pandemics prior to COVID-19, resulting in tens of millions of deaths. Most of these pandemics have been caused by one or another type of respiratory viruses.
1918-1919 flu pandemic (Spanish flu): The first pandemic of the 20th century, started in 1918 and spread around the world, in three waves, infecting an estimated 500 million, almost a third of the world population at the time, and killing nearly 50 million. In the pre-partition India alone, it caused between 12 – 17 million fatalities. This pandemic of respiratory illness was caused by H1N1 virus, a sub-type of Influenza A virus, the same virus that caused the swine flu pandemic decades later. The pandemic is thought to have originated in either USA or France and spread throughout the world, as World War I was raging. However, since it was first reported by Spanish newspapers, it was quickly dubbed as Spanish flue. The pandemic subsided by mid-1919, after the milder third wave ended.
1957–1958 influenza pandemic (Asian flu): This respiratory Pandemic started in 1957 in China and engulfed the world, in two waves, causing worldwide fatalities, estimated to be between one and four millions. This pandemic was caused by a sub-type of Influenza A virus, the H2N2. A vaccine was developed and was available for public use by end of 1957, stemming the tide of the pandemic, which fizzled out by 1958.
1968 flu pandemic (Hong Kong Flu): The first case of this respiratory illness, caused by H3N2 sub-type of Influenza A virus, was recorded in Hong Kong in July 1968. By end of the year, the disease had spread to Asia, Europe, Africa, South and North America. The worldwide fatalities were estimated to be around one million. The vaccine was available by the end of 1968 and the Pandemic subsided by early 1969.
HIV AIDS Pandemic (1981 – ongoing): The Human Immunodeficiency Viruses (HIV-1 and HIV-2) are subtype of Lentivirus. They attack the human immune system, rendering the infected person prone to various bacterial and viral infections as well as cancers – the condition called Acquired Immune Deficiency Syndrome (AIDS). HIV has, so far, infected 75 million and killed close to 32 million, with active cases in every country. Although, there is no treatment available for the HIV virus, but a life-long regimen of antiviral drugs can delay the progression to AIDS almost indefinitely. Despite many efforts, a vaccine for HIV could not be developed to date.
The 2002 SARS Pandemic: The Severe Acute Respiratory Syndrome (SARS) is a respiratory diseases, caused by SARS-COV Coronavirus. The disease first appeared in in China during 2002 and spread to the neighboring countries of Southeast Asia. A few cases were also reported from Europe, South and North America. The probable source of this zoonotic virus was traced to Horseshoe Bats. The virus infected around 8,000 throughout the world with close to 10% fatality rate. The infections ended by mid-2003 and since then, no case has been reported. There is no specific treatment or vaccine for SARS.
The 2009 Swine Flu Pandemic: This flu pandemic started in Mexico in early 2009, by end of the year, the rate of infections started to go down and WHO declared the pandemic over by August 2010. The respiratory diseases, caused by a variant of H1N1 Influenza A virus, infected an estimated 700 million to 1.4 billion worldwide and caused approximately 300,000 to 500,000 deaths. A vaccine was developed in 2009 and the severe cases are usually treated through a combination of anti-viral drugs.
MERS Pandemic 2012: The Middle East Respiratory Syndrome (MERS), caused by MERS-COV coronavirus was first reported from Saudi Arabia and has since been reported from more than 26 countries, with major outbreaks in South Korea (2015) and Saudi Arabia (2018). The virus is transmitted from camels to humans with very low human to human transmission, this is one of the reasons of low infection rates – 2519 cases and 866 deaths since 2012. To date, there is no specific treatment or vaccine for MERS.
As we can see, the good thing about pandemics is that no matter how deadly or contiguous they are, they eventually come to an end. Whether it was the plague or 1918 flu pandemic, they were over after a certain period of time, but the rate and speed of infection depends on our behavior and response.
Mitigating the effects of a pandemic depends on how prepared we are when the pandemic hits. Regional, national and sub-national preparedness plans are central to the preparedness efforts. The plans must articulate, at the minimum, healthcare systems preparedness and response; laboratory preparedness and response; a plan for a quick surge in the capacity in case of an epidemic or pandemic; a strategy for coordination and division of responsibilities among various stakeholders; and above all a proper plan for risk communication to the public and countering rumors and fake news from the very start. Frequent simulation exercises are a must to test the plans practically and take corrective measures as necessary, so that everything works as planned, when it is time for action.
Pandemics are and have always been a fact of life. The next pandemic, once the COVID-19 subsides, is the matter of when not if. Here lies our choice – would we like to be caught off guard as the next pandemic hits or should we have acceptable level of preparation and readiness in place to deal with it.