How Deadly Is the Coronavirus?
After analyzing data from outbreaks on cruise ships and more recently from surveys of thousands of people as well as conducting dozens of studies suggests that Covid-19 kills between 0.3% to 1.5% of people infected. Most studies put the rate between 0.5% and 1.0% (for every 1,000 infected about 5 to 10 people would die on average).
This research suggests thatthe new coronavirus is 6 times deadlier than the seasonal flu (.1%), but not as lethal as Ebola (50% in most recent outbreak) The coronavirus is killing more people (currently 609,000 people) than the deadlier diseases (11,325 for Ebola, 774 for SARS and 858 for MERS), because it is more infectious. Diseases such as SARS, MERS, and Ebola are much deadlier, with case fatality rates ranging from roughly 10% to 50%.
“It’s not just what the infection-fatality rate is. It’s also how contagious the disease is, and Covid is very contagious,” said Eric Toner, an emergency medicine physician and senior scholar at Johns Hopkins Center for Health Security. “It’s the combination of the fatality rate and the infectiousness that makes this such a dangerous disease.”
“It’s very difficult to measure, but robust studies are finding a clear signal in the noise,” said Timothy Russell, a research fellow at the London School of Hygiene and Tropical Medicine. A study by Dr. Russell and colleagues published in February that examined data from China and an outbreak on the Diamond Princess cruise ship set it at .6%.
With 14.7 million infected and 609,000 dead, nearly 25% of the fatalities in the U.S, the raw numbers say it kills 4.2% of those infected. When you add in the number of assumed cases not reported (roughly 10 for every 1 reported) that number drops. When it comes to estimates for the fatality rate, some researchers take the known cases and numbers of deaths, then estimate the proportion missed or asymptomatic cases, researchers then adjust for that missed death that they believe are not reported. Other researchers predict estimates based on results from antibody test surveys. ( Regardless of the approach, researchers use complex mathematical models and statistical techniques to fine-tune their estimates.)
When researchers combined 26 different studies estimating the infection-fatality rate in different parts of the globe it resulted in a .68% fatality rate overall, with a range of 0.53% to 0.82%, according to a report posted in July on the preprint server medRxiv. (Not reviewed by other researchers.)
“To say that we will ever have one absolute true estimate is erroneous. We can get an idea of a trend, but we need to be mindful that this can change and vary,” said Lea Merone, a public-health physician and health economist at James Cook University in Australia who co-wrote the paper. “It is context dependent.”
The CDC is now reporting an estimate of 0.65% as of July 10, higher than its previous estimates. For those individuals above 65 it is 5.6% (40 times the risk of someone in their 50s).
“There’s this narrative I think a lot of people have that you get the disease and you die, or you’re fine. And that’s not true,” Dr. Toner said. “There’s a large range of health-care consequences for people who get severely ill, not just death.”