When will the pandemic end? of these months in, with over 37 million COVID-19 cases and over 1 million deaths globally, you'll be wondering, with increasing exasperation, how long this may continue.
Since the start of the pandemic, epidemiologists and public health specialists are using mathematical models to forecast the longer term in a trial to curb the spread of the coronavirus.
But communicable disease modeling is hard. Epidemiologists warn that "[m]odels aren't crystal balls," and even sophisticated versions, like people who combine forecasts or use machine learning, can't necessarily reveal when the pandemic will end or what number of people will die.
As a historian who studies disease and public health, I suggest that rather than looking forward to clues, you'll recollect to work out what brought past outbreaks to a detailed – or didn't.
Where we are now within the course of the pandemic
In the time period of the pandemic, many folks hoped the coronavirus would simply dissolve. Some argued that it might disappear on its own with the summer heat. Others claimed that herd immunity would kick in once enough people had been infected. But none of that is going on.
A combination of public health efforts to contain and mitigate the pandemic – from rigorous testing and call tracing to social distancing and wearing masks – are proven to assist.
Given that the virus has spread almost everywhere within the world, though, such measures alone can't bring the pandemic to an end. All eyes are now turned to vaccine development, which is being pursued at unprecedented speed.
Yet experts tell us that even with a successful vaccine and effective treatment, COVID-19 may never flee. whether or not the pandemic is curbed in one a part of the globe, it'll likely continue in other places, causing infections elsewhere.
And whether or not it's now not an instantaneous pandemic-level threat, the coronavirus will likely become endemic – meaning slow, the sustained transmission will persist. The coronavirus will still cause smaller outbreaks, very similar to seasonal flu.
The history of pandemics is filled with such frustrating examples.
Once they emerge, diseases rarely leave
Whether bacterial, viral, or parasitic, virtually every disease pathogen that has affected people over the last several thousand years continues to be with us, because it's nearly impossible to completely eradicate them.
The only disease that has been eradicated through vaccination is smallpox. Mass vaccination campaigns led by the planet Health Organization within the 1960s and 1970s were successful, and in 1980, smallpox has declared the primary – and still, the sole – human disease to be fully eradicated.
So success stories like smallpox are exceptional. it's rather the rule that diseases come to remain.
Take, for instance, pathogens like malaria. Transmitted via a parasite, it's almost as old as humanity and still exacts an important disease burden today: there have been about 228 million malaria cases and 405,000 deaths worldwide in 2018.
Since 1955, global programs to eradicate malaria, assisted by the employment of DDT and chloroquine, brought some success, but the disease remains endemic in many countries of the world South.
Similarly, diseases like tuberculosis, leprosy, and measles are with us for several millennia. And despite all efforts, immediate eradication continues to be not visible.
Add to this mix relatively younger pathogens, like HIV and Ebola virus, together with influenza and coronaviruses including SARS, MERS, and SARS-CoV-2 that causes COVID-19, and therefore the overall epidemiological picture becomes clear.
Research on the worldwide burden of disease finds that annual mortality caused by infectious diseases – most of which occurs within the developing world – is sort of one-third of all deaths globally.
Today, in an age of world traveling, temperature change, and ecological disturbances, we are constantly exposed to the threat of emerging infectious diseases while continuing to suffer from much older diseases that remain alive and well.
Once added to the repertoire of pathogens that affect human societies, most infectious diseases are here to remain.
The plague caused past pandemics – and still pops up
Even infections that now have effective vaccines and coverings still take lives. Perhaps no disease can help illustrate now better than the plague, the only most threatening communicable disease in human history. Its name continues to be synonymous with horror even today.
Plague is caused by the bacterium Yersinia pestis. There are countless local outbreaks and a minimum of three documented plague pandemics over the last 5,000 years, killing many voluminous people. the foremost notorious of all pandemics was the black plague of the mid-14th century.
Yet the bubonic plague was removed from being an isolated outburst. Plague returned every decade or perhaps more frequently, on every occasion hitting already weakened societies and taking its toll during a minimum of six centuries.
Even before the sanitary revolution of the 19th century, each outbreak gradually died down over the course of months and sometimes years as a result of changes in temperature, humidity, and also the availability of hosts, vectors, and a sufficient number of susceptible individuals.
Some societies recovered relatively quickly from their losses caused by the bubonic plague. Others never did. for instance, medieval Egypt couldn't fully live through the lingering effects of the pandemic, which particularly devastated its agricultural sector.
The cumulative effects of declining populations became impossible to recoup. It led to the gradual decline of the Mamluk Sultanate and its conquest by the Ottomans within but two centuries.
That exact same state-wrecking plague bacterium remains with us even today, a reminder of the very long persistence and resilience of pathogens.
Hopefully, COVID-19 won't persist for millennia. But until there is a successful vaccine, and sure even after, nobody is safe.
Politics here are crucial: When vaccination programs are weakened, infections can come roaring back. Just take a look at measles and polio, which resurge as soon as vaccination efforts falter.
Given such historical and contemporary precedents, humanity can only hope that the coronavirus that causes COVID-19 will encourage be a tractable and eradicable pathogen.
But the history of pandemics teaches us to expect otherwise. The Conversation
Nükhet Varlik, professor of History, University of South Carolina.
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