Covid-19 compared to other pandemics this century

According to microbiologist Siouxsie Wiles, compared to other pandemics this century Covid-19 is a bad roll of the dice.

Stuff: We lost this round of pandemic dice

I think it helps to think of these outbreaks and pandemics as a handful of dice.

The dice represent:

  • The microbe and how it spreads.
  • What symptoms it causes.
  • How it can be treated and prevented.
  • How each dice falls influences how the outbreak plays out.

With Covid-19, we’ve rolled almost the worst possible combination, with a collection of ones.

Covid isn’t as lethal as the likes of Ebola, but as symptoms are often not noticed or mild, and take time to present, Covid can spread before it is discovered.

Wiles details the other pandemics in the last 20 years, and compares aspects of them to Covid.

Sars (2002-2004)

Sars appeared in late 2002, also caused by a coronavirus that spreads through the respiratory route. Unlike Covid-19, people with Sars had a high fever early in their infection. That made it easier to identify infected people and stop human-to-human transmission.

By mid-2004, Sars was gone and hasn’t been seen since. By then 8000 people had been infected and over 800 had died. Cases had spread to almost 30 countries and territories.

Covid-19 also emerged in a globally connected part of the world and at a time of year when lots of people were moving about.

H1N1 (early 2009 to August 2010)

H1N1 was a variant of the influenza viruses from humans, birds, and pigs that caused a pandemic from early 2009 to August 2010. Like normal seasonal flu, H1N1 spread through the respiratory route. But unlike normal flu, it was more likely to cause breathing difficulties in young, healthy people. Thankfully, a vaccine was available by late 2009. It’s thought H1N1 caused about 500,000 deaths. 

That was over about 18 months.

Ebola (December 2013-June 2016)

The largest Ebola outbreak began in Guinea, West Africa in December 2013 and spread to Liberia and Sierra Leone. Ebola transmits through bodily fluids from symptomatic people. That means it’s easier to stop than Covid-19, in which people are infectious before they realise they have the virus.

While vaccines were in clinical trials by mid-2015, the Ebola outbreak was mainly brought under control by stopping human-to-human transmission. It also helped that it was in a part of the world that isn’t quite so globally connected. The outbreak was officially declared over in June 2016. By then over 28,000 people had been infected and over 11,000 had died.

Ebola had a very high death rate for those infected, but was much more easily contained.

Zika (2015-2016)

Zika is the virus that causes babies to be born with small heads. It’s spread by mosquito bite and caused an outbreak in the Americas, Pacific, and Southeast Asia in 2015 and 2016. In many mosquito species, the females feed on people one time before laying their eggs. Zika is carried by mosquitoes that feed more than once. As a result, they spread the virus from infected to uninfected people as they ate. The outbreak was largely controlled by getting rid of mosquitoes carrying the virus.

Current Covid totals (Worldometer):

  • Total detected cases – 25 million
  • Total attributed deaths – 848,925

The closest comparison is H1N1, with about half the deaths. A vaccine was available within the year it began but it still nearly a year to eliminate it.

New Zealand has got off lightly so far, with just 1,729 cases and 22 deaths.

Initially Australia had a comparable result but after a big outbreak in Victoria cases have jumped to 25,166 and deaths to 611.

We have been mostly successful at containing Covid but the current outbreak in Auckland is a concern. It shows how quickly things can change.

Pandemics and their ends

When will the Covid-19 pandemic end? It depends on what sort of end.

A social end to a pandemic is when people grow tired of panic mode and learn to live with a disease. There are signs of reaching this point in New Zealand now, but that doesn’t rule out a resurgence at some time in the future.

A medical end can be difficult to determine, and only after it has ended. Id it ends at all, some diseases just carry on, like the common flu.

MSN/New York Times: How Pandemics End

According to historians, pandemics typically have two types of endings: the medical, which occurs when the incidence and death rates plummet, and the social, when the epidemic of fear about the disease wanes.

Endings “are very, very messy,” said Dora Vargha, a historian at the University of Exeter. “Looking back, we have a weak narrative. For whom does the epidemic end, and who gets to say?”

Will that happen with Covid-19?

One possibility, historians say, is that the coronavirus pandemic could end socially before it ends medically. People may grow so tired of the restrictions that they declare the pandemic over, even as the virus continues to smolder in the population and before a vaccine or effective treatment is found.

“I think there is this sort of social psychological issue of exhaustion and frustration,” the Yale historian Naomi Rogers said. “We may be in a moment when people are just saying: ‘That’s enough. I deserve to be able to return to my regular life.’”

It is happening already; in some states, governors have lifted restrictions, allowing hair salons, nail salons and gyms to reopen, in defiance of warnings by public health officials that such steps are premature. As the economic catastrophe wreaked by the lockdowns grows, more and more people may be ready to say “enough.”

To extent that has been happening in New Zealand over the last two weeks. Reports of a rush back to shopping yesterday, the start of the first weekend since we lowered to Level 2 restrictions that allowed all shops to re-open, suggest a getting back to normal. I drove through town yesterday and traffic was a busier than a normal Saturday, And I went for a trip right along the west side of Otago Harbour. It was quiet mid-morning but it was busier than normal by the middle of the day.

“There is this sort of conflict now,” Dr. Rogers said. Public health officials have a medical end in sight, but some members of the public see a social end.

The challenge, Dr. Brandt said, is that there will be no sudden victory. Trying to define the end of the epidemic “will be a long and difficult process.”

Many attempts are being made to have a vaccine ready by the end of the year, but it’s like to be months away at least. The Covid-19 virus is certain to continue, even if the fears subside.


Pandemics from history

Bubonic Plague

Historians describe three great waves of plague, said Mary Fissell, a historian at Johns Hopkins: the Plague of Justinian, in the sixth century; the medieval epidemic, in the 14th century; and a pandemic that struck in the late 19th and early 20th centuries.

The medieval pandemic began in 1331 in China. The illness, along with a civil war that was raging at the time, killed half the population of China. From there, the plague moved along trade routes to Europe, North Africa and the Middle East. In the years between 1347 and 1351, it killed at least a third of the European population. Half of the population of Siena, Italy, died.

That pandemic ended, but the plague recurred.

One of the worst outbreaks began in China in 1855 and spread worldwide, killing more than 12 million in India alone.

It is not clear what made the bubonic plague die down.

Smallpox

Among the diseases to have achieved a medical end is smallpox. But it is exceptional for several reasons: There is an effective vaccine, which gives lifelong protection; the virus, Variola minor, has no animal host, so eliminating the disease in humans meant total elimination; and its symptoms are so unusual that infection is obvious, allowing for effective quarantines and contact tracing.

But while it still raged, smallpox was horrific. Epidemic after epidemic swept the world, for at least 3,000 years.

It is thought to have been present in India as early as 1500 BCE, China 1122 BCE and Egypt 1145 BCE.

In 18th-century Europe it is estimated 400,000 people per year died from the disease, and one-third of the cases resulted in blindness.

It is estimated to have killed up to 300-500 million people in the 20th century. Two million died from smallpox in 1967.

The last naturally occurring case was diagnosed in October 1977.

1918 (Spanish) Flu

This raced around the world at the end of Word War 1, killing 50-100 million people.

After sweeping through the world, that flu faded away, evolving into a variant of the more benign flu that comes around every year.

There were about 9,000 deaths in New Zealand, 2.500 of them Māori.

Hong Kong Flu

In the Hong Kong flu of 1968, one million people died worldwide, including 100,000 in the United States, mostly people older than 65. That virus still circulates as a seasonal flu, and its initial path of destruction — and the fear that went with it — is rarely recalled.

Swine flu

This was a variant strain of the 1918 Spanish flu. It is estimated to have caused somewhere between 150,000 and 575,000 deaths, and it is estimated that 700-1500 million were infected. Fortunately most people were only mildly affected.

Ebola

In 2014 more than 11,000 people in West Africa had died from Ebola, a highly infectious viral disease that was often fatal.

Covid-19

This has spread around the world and in about five months over 308,000 people have died, but this total is likely to grow quite a bit yet – the death toll has doubled over the last month.

In New Zealand the last of 21 deaths was on 6 May, and cases have just about stopped – the peak daily cases were from 24 March and had dropped to 29 by 11 April.

Virtually shutting down the borders has stopped the re-introduction of Covid. But how long will we keep our borders closed? While we may socially think the health problem is over some significant restrictions could persist for months.

We are no longer shut in our homes but we remain shut in our country.

But we have the benefit of modern health care and modern science.