Coronavirus is probably both worse and better than people think
Over the last nine flu seasons, the Centers for Disease Control (CDC) estimated that 337,000 people died in the U.S. due to the flu. They further estimated that there were almost 258 million cases of the flu in the U.S. during the same time frame. This works out to an estimated average mortality rate of about 0.13% or 0.0013. A key word in those statements of fact is "estimated."
Clearly, not everyone who gets the flu each year is hospitalized or even goes to a doctor. Also, not everyone who dies because of the flu has that listed as the cause of death. For example, an older person with a bad case of the flu may die of heart failure. Since this person would not have died then without the flu, he died of the flu despite heart failure being his listed cause of death.
So, based on research over the years, the CDC has ways it estimates the number of cases of the flu based on hospitalizations and doctor visits for the flu. It similarly has ways to estimate the number of deaths from the flu above those reported as flu deaths.
What does this have to do with COVID-19 being worse or better than you think? Well, COVID-19 is too new for the CDC or other health organizations or researchers to have a good way to estimate the total number of cases.
For many people, the symptoms of COVID-19 are mild — milder than the flu for a typical person in various recent flu seasons. As pointed out above, many people don’t go to a hospital or even a doctor with the flu. With even milder COVID-19 symptoms, probably many people who got it never went to a doctor or a hospital. Thus, probably far more people have had COVID-19 than the numbers currently being reported. Particularly in the early days of this disease, many people probably went undiagnosed and untreated for their mild symptoms. So COVID-19 is worse than people think, because many more people have probably gotten it.
But this also means COVID-19 is better than or at least not as bad as people think. Because many more people have probably gotten COVID-19 than the number reported and none or very, very few of these people have died, the mortality rate of COVID-19 is probably much lower than the currently reported 7% for cases where there has been an outcome. The more uncounted people who have gotten this disease, the smaller the actual mortality rate would be if they were counted.