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It's not the first virus to spread rapidly from country to country, nor is it the first to be declared a pandemic — but within weeks, people have lost jobs, and even their lives as a result of COVID-19.
Governments around the world have scrambled to respond to the threat of coronavirus — despite the disease having a far lower mortality rate than other respiratory diseases like SARS or MERS.
Here's why the world has been turned upside down due to COVID-19.
It's less deadly than SARS — that's why it's killing more people overall
There are obvious similarities between COVID-19 and the first pandemic of the 21st century, Severe Acute Respiratory Syndrome (SARS), which reached the public consciousness in early 2003.
Both SARS and COVID-19 are types of coronavirus, and both are thought to have originated in a Chinese "wet market".
But while SARS made its way to about 30 different countries before being contained, it infected just over 8,000 people and killed 774 by the time the World Health Organisation (WHO) declared the pandemic over in mid-2003.
On its own, the figure is huge — but not when compared to COVID-19, which so far has resulted in more than 1.5 million recorded cases and 88,500 deaths.
SARS kills between 14 and 15 per cent of people it infects.
We still don't know the exact death rate of COVID-19 as the data continues to come in, but the WHO has said initial figures indicate the crude mortality rate is between 3 and 4 per cent.
So why has COVID-19 killed so many more people than SARS?
According to Peter Collignon, an infectious diseases expert from the Australian National University's Medical School, it's partly due to the range of effects COVID-19 can have on people.
He said the trouble with the virus was it could go undetected because the majority of infected people experienced only mild symptoms.
"Perversely, when you have a disease like SARS that has a relatively high mortality rate, that actually spreads less because people notice it much quicker," Professor Collignon said.
"It's like Ebola — if you have a large percentage of the people who get it get very sick and die, before it spreads very far you know about it."
Associate professor of Medicine at ANU Sanjaya Senanayake said viruses like COVID-19 thrived by keeping humans alive.
"In fact, to be an effective virus it will want to keep its hosts alive so it can continue doing … its infecting," he said.
When asked why COVID-19 had triggered such a strong response from governments around the world, Dr Senanayake said: "It's highly infectious and none of us are immune."
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Apart from its death rate — what else is at play here?
The other frightening issue, according to Stuart Tangye from the Garvan Institute of Medical Research, is that many people are silent carriers who don't even know they have COVID-19 until it's too late.
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"Basically, there's a whole lot of healthy people out there who are carrying the virus, early on, who just didn't know they were spreading it around," Professor Tangye said.
"The Ruby Princess is a classic and tragic example.
"There were a couple of people on the boat who were symptomatic, they let everyone get off, and suddenly realised there were hundreds of people who were virus positive, taking the virus with them and spreading it around parts of the country and parts of the world."
Professor Tangye said this was different to cases of SARS or Middle Eastern Respiratory Syndrome (MERS) where people typically displayed symptoms when they were infectious.
"The onset of symptoms there very much came not long after infection, so you were sort of symptomatic and therefore isolated quickly," he said.
What about the flu?
We hear about the flu a lot in comparison to COVID-19.
There are estimates that globally, influenza has caused as many as 646,000 deaths per year.
What the experts are saying about coronavirus:
But Professor Tangye said there were three main things that separated influenza from COVID-19: herd immunity, vaccines and treatment — like antiviral medications which can sometimes shorten the duration of the flu.
He said given COVID-19 did not yet have any of those things, people effectively had no protection from the highly infectious virus.
The mortality rate of COVID-19 is also thought to be higher than that of most strains of the flu.
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Topics: government-and-politics, infectious-diseases-other, federal-government, health, respiratory-diseases, covid-19, community-and-society, australia
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