Covid Mortality Rates Lower than Predicted

Here’s some good news for a change. The mortality rates for the Covid-19 virus are lower than many predictions. While the number of individuals testing positive is still climbing, and some are still dying, the rate of mortality is actually quite low.

In an earlier post (Covid-19 Less Deadly Than Expected) three months ago, I reported the mortality rate of Covid-19 was estimated by the World Health Organization (WHO) at 3.4%. This estimate was based on limited data, especially concerning the number of infected individuals who did not die. As many as 80% of Covid-19 infected individuals have few or no symptoms. As more and more of these individuals are identified with improved testing, the rate of mortality will decline even more.

A study performed in April in Santa Clara County, California, estimated the true infection mortality rate as somewhere between 0.12% to 0.2% based on additional data. This is much closer to the seasonal influenza rates in an average season.

Brianna Abbott and Jason Douglas, writing in WSJ, report the latest research examined deaths out of the total number of infections, which includes unreported cases. This research estimates the mortality rate between 0.3% and 1.5%. Most studies put the rate between 0.5% and 1%, meaning that for every 1,000 people infected, somewhere between five and ten die on average.

This places Covid-19 on a scale compared to other viruses such as influenza and Ebola. It is deadlier than the average influenza virus but far less lethal than Ebola and other lethal viruses that have emerged in recent years. Researchers say the corona virus is killing more people because it is more infectious than other deadlier diseases.

Dr. Eric Toner, and emergency medicine physician at Johns Hopkins Center of Health Security says, “It’s not just what the infection-fatality rate is. It’s also how contagious the disease is, and Covid is very contagious. It’s the combination of the fatality rate and the infectiousness that makes this such a dangerous disease.”

There are multiple ways to calculate mortality rates and researchers differ on which is the best method. An analysis of 26 different studies estimating the infection-fatality rate in different parts of the world found an aggregate estimate of 0.68%, range of 0.53% to 0.82%. The CDC is now using an estimate of 0.65%as its official number since July 10.

Moreover, this is largely a disease that is fatal mostly in the elderly, especially those who live in nursing homes. As I wrote in June (Covid-19 and the Nursing Homes Disaster), 42% of all Covid-19 deaths happened in these facilities that house 0.6% of the population. Below is a chart showing age-related deaths:

This new data gives us more evidence to conclude that Covid-19 is a serious and deadly disease for a small percentage of the population of the world, mostly the elderly. For the rest of the 99.4%, it is unlikely to cause serious disease.