The world is currently reeling under the burden of the Covid-19 pandemic. However, pandemics are not a new phenomenon. History is replete with instances of pandemics of varying proportions. These pandemics in the past offer valuable lessons that could inform our management of the Covid-19 pandemic.
This article attempts to trace the similarities among different influenza pandemics and compare them with coronavirus pandemics by tracing patterns in death toll and their duration. The study is then extended to compare Spanish Flu and COVID-19 specifically. Age specific mortality of these two pandemics in the USA is compared to draw lessons. The effect of war and conflict on these pandemics is also briefly looked at.
Influenza & Coronavirus
There have been five major influenza pandemics in the last 3 centuries (19th, 20th and 21st) , all of them caused by different subtypes of Influenza A virus (H1N1, H2N2 etc.). Similarly, there have been three major coronavirus pandemics, all caused by different subtypes of the coronavirus (SARSCoV-1, SARSCov-2 etc.). Both the influenza virus and the coronavirus have zoonotic origins, similar outbreak processes and transmission dynamics (Damme, et al., 2020). Moreover, both influenza virus (Fig.1) and the coronavirus (Fig.2) exhibit a pattern of persisting in the ecosystem even long after they cease to be a ‘pandemic’, causing infections and deaths, before another subtype of its kind emerges which causes a new pandemic.
Spanish-Flu and Covid-19
Preparing for Future Pandemics
From Fig.1 and Fig.2 it can be observed that all the influenza and coronavirus pandemics have had relatively lower death tolls barring two – Spanish Flu in the case of Influenza and Covid-19 in the case of coronavirus. Even before the outbreak of the 2009 Swine-Flu pandemic, there were preparations in the scientific community for handling a novel influenza pandemic considering the previous pandemic bouts and the prevalence of the virus and its potential mutation (CDC, 2018). While such a preparative strategy helped in containing the casualties of Swine-Flu, it is imperative to extend such a strategy to coronavirus pandemics as well.
Considering the fact that zoonotic pathogens infect 2.4 billion people in developing countries every year, causing 2.2 million deaths (Bank, 2013), there is a high possibility that another coronavirus (or influenza) pandemic may strike even after Covid-19 ceases to be a pandemic.
Age specific Mortality
Unlike many other pandemics, Spanish-Flu of 1918 had more casualties among the 20-40 age group (refer Fig.3). This robbed families of their breadwinners, which created more demand for labour. Like most pandemics, the poor and immigrants died in large numbers during the Spanish-Flu. But the realisation that nobody was immune from the virus, is argued to have created a cognitive shift that led to the social medicine approach in public-health in many European nations. There is also evidence suggesting that the 1918 Flu contributed to the baby boom of the 1920s, since the pandemic left behind a smaller-healthier population that reproduced at higher rates (Spinney, 2018).
Although Covid-19 casualties are more among the 65+ age group (refer Fig.4), recent reports from the second wave in India indicate an increase in casualties among the 20-40 year olds (TOI, 2021). If similar waves happen around the world, then this can lead to a decrease in the number of working age population, which can lead to an increase in demand for migrant workers. Similarly, discussion around the post-Covid-19 baby boom and increased investment in public-health could be better informed by lessons from the Spanish-Flu.
War & Conflict Zones
The Spanish-Flu had spread during the First World War and more people had died of the pandemic than during the Great War. War and conflict not only help the spread of pathogens through intense human movement, they also lead to the collapse of public health infrastructure, poor health services, and increased press censorship. In 2001, more than half of the outbreaks of international importance occurred in conflict zones (Máire A Connolly, 2002). All this calls for a focus on Covid-19’s impact on conflict torn regions like Yemen, Afghanistan and Syria.
In our earlier article, it was observed that the 21st century could see more deaths due to pandemics than the previous centuries. The coronavirus pandemic could be one of the many pandemics we could see in this century considering the increase in livestock that aids zoonotic transmission as well as factors like globalisation, migration and proliferation of cities. Viruses like Nipah which caused only a few casualties in its first avatar could evolve into variants with the potential to cause pandemic in due course of time. Going forwards increase in public health expenditure, press freedom, ‘One Health’ approach and interventions for peace in conflict regions are some measures that could be taken.
This article was written by Sonal Kuruvilla and Mohammed S. under guidance of Dr. R P Pradhan, CPPR Distinguished Fellow