Did The Coronavirus get more deadly? The death rate explained.

 

Trump says Covid-19 isn’t that fatal. Here’s what we know

In early March, the death toll from the coronavirus outbreak had climbed to more than 4,500 people a few days before, the World Health Organization — for the first time — issued a Covid-19 case mortality rate (CFR).

That was no minor estimate.

“Globally, about 3.4 percent of the reported COVID-19 cases have died,” WHO Director-General Tedros Aloom Ghebreussus told a press briefing. This rate describes the proportion of deaths among confirmed cases. This was higher than the previous coronavirus CFR estimate (2 percent in China), far higher than seasonal flu (which kills 0.1 percent of infected people on average), and even worse than the Spanish flu pandemic (which killed an estimated 2 to 3 percent of those infected).

It’s no surprise that, very quickly, media around the world interpreted the news as evidence that the disease is fatal from fear, and Twitter was buzzing with speculation about covid-19’s real mortality. The number spread so fast so far, even as President Trump tried to worry Fox News on March 5 and tamp down: “I think the 3.4 percent number is actually a false number. Now, it’s just my hunch but based on a lot of conversations. Personally, I would say that the number is way under 1 percent.

Finally, the 3.4 percent figure appears to have sown more confusion than clarity. While a WHO spokesman called the number “current global snapshot,'” it misled something: it was delivered without context, major factors that omitted to determine the severity of a disease. In fact, we still don’t know covid-19 exact mortality — but we have estimates based on some models that are more sophisticated than just dividing coronavirus deaths by cases.

Epidemiologists and modelers studying disease Covid-19 said Vox is about 1 percent of a more reliable global case mortality rate — but there’s still a lot we learn about the disease. And even when we better understand how deadly this virus is, it’s likely to see very different countries for the country.

What we know about how headly the coronavirus is

coronavirus death rate by country

 

An important piece of information we still need is how many people in a population have the virus. It is the acumen in the CFR equation.

When Tedros made his remarks, the WHO had registered 3,112 deaths and 90,869 cases. You get 3.4 percent, dividing deaths from cases. But that denominator is actually very fuzzy. So far, many countries — even those with sophisticated health systems, like the U.S. — have struggled to get enough testing and running. And, to date, a lot of attention has been paid to examining those who travel to the countries affected, not the wider population.

This means, in many places, health authorities are only picking up a subplot of the sick — and perhaps the most serious cases, given that nearly 80 percent of people with coronavirus have a lighter case. (Remember: The sickest are usually those who show up at the doctor’s offices and hospitals, while there may be hundreds or thousands of others with viruses who don’t bother going to show symptoms or see a doctor. That is why CFR can often look very bad in the early days of the outbreak.

As of Feb. 20, which also reported lots of regional disparities in the disease deadline even within China: 3.8 percent on average but 5.8 percent in Wuhan, Hubei Province (where the virus first emerged), and 0.7 percent in other regions in China. (A WHO spokesman acknowledged these regional differences and said we are “likely to see something similar in different countries and outbreaks.”)

One final thought: CFRs change over time. That is exactly what happened in China, as you can see in this figure from the WHO. Even the first and most difficult-hit province, Hubei, saw public health measures as its mortality rate declined and improved in identifying physicians and treating people with the disease:

As this epidemic wears on the threat, we could see even more deaths – which may not increase the CFR if those mild cases appear. “It takes a long time to die from Covid-19,” said University of Toronto epidemiologist David Fisherman. “We estimate the length of living in cases that died on an average of 28 days in the ICU in China – three days in the hospital and 25 days in the ICU.

A batter way to calculate the covid-19 death rate

The ideal way to arrive at an accurate CFR involves a survey of affected populations, including those who have antibodies for the virus, including those who didn’t even know that their sine. The pass was it. That will give experts denominators, or real case tolls, into the CFR equation. “While we’ve done [that] — and I’m sure it will happen sometime in the future — there are going to be some people that have mild infections or asymptomatic infections that we’re not picking.”

As it stands, no such serology tests have been completed, although China has approved at least two, and Singapore says it is already using an experimental test to check for antibodies in patients there.

Meanwhile, we have disease modelers who can give us a provisional picture of the Covid-19 deadline, accounting for things like reporting deaths and delaying the reporting of potentially innumerable cases.

In a new but yet peer-reviewed preprint of Switzerland’s University of Bern, researchers have done that, using data on the outbreak from China’s CDC. They came up with an overall CFR of 1.6 percent — Covid-19 suggested less lethal than SARS, which had a CFR of about 10 percent. That is less than the WHO estimates.

Importantly, the researchers also found a wide variation across the age spectrum: Less than 1 percent of people in their 20s die from the virus, they estimate, while the rate shoots up to 18 percent for 80-year-olds.

“It’s based on a lot of 1.6 percent [figure] assumptions we feel comfortable with, but it’s not hard data,” Julian Riou, a Burn research fellow and author on the paper, stressed. “It’s more accurate to [an effort] to know about the prejudices we know about.” It’s also based entirely on China’s data — and, again, outbreaks in other countries will likely play differently.

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