On June 15, the US Centers for Disease Control and Prevention released a study based on studying 1.3 million cases of the coronavirus disease reported to CDC between January 22 and May 31. Of these, around 290,000 people had significant underlying conditions (the study is clear that while more may have had such conditions, CDC did not have information on these). None of these numbers is insignificant. 1.3 million is a large enough sample. So is 290,000.
The study is a treasure trove of information on the people affected by Covid-19. While each population is different, there is a high likelihood that this information will also be applicable to people infected with the virus here.
So, what do we know?
ONE: The chances of the virus infecting men and women are roughly the same. Put otherwise, there’s an equal chance of the virus infecting men and women.
But women do seem more resilient to the virus as indicated by previous research from Italy.
Only one in eight women infected required hospitalisation as compared to one in six men; and one in 16 men died, as compared to one in 20 women.
TWO: People over the age of 80 are the most likely to get the disease. How likely? Well, there is a 0.9% chance of someone over the age of 80 contracting the infection. The probability for the overall population is 0.4%. Interestingly, there is a 0.54% chance and a 0.55% chance of people between the ages of 40 and 49, and 50 and 59 respectively contracting the disease, higher than the chances of anyone between the ages of 60 and 79 contracting it. Children under the age of 9 have the least probability of being infected, 0.05%.
The important thing is to understand these probabilities. They are not very high but also not very low — the probability of being killed in a road accident in the US is around .012%.
As an aside, CDC’s study shows that the median age across these 1.3 million cases, was 48. That’s not too high. The median or the “middle” is a good statistical measure of the typical age of those infected by the disease. While 48 isn’t young, it definitely isn’t old either.
THREE: Only 14% of those infected were hospitalised (this is not to be read as “needed hospitalisation” because that number will likely be higher), and around 16% or one in every six people admitted in hospitals needed ICU treatment.
It’s important to note that unlike in India, where, at least in the initial stages of the pandemic’s run, even people with mild symptoms or no symptoms were admitted in hospitals, in the US, it is usually people in distress from the disease who were (and are) admitted. That could explain why 39% of the people hospitalised in the US died. But overall, only around 5% of those infected died.
FOUR: Almost half (45.4%) of the people with underlying conditions — what we call co-morbidities; usually heart problems, diabetes, or lung disease, although, in India, kidney disease seems to be a co-morbidity that has a high correlation with Covid-19 fatalities — were hospitalised. In contrast, according to CDC, only 7.6% without an underlying condition were hospitalised.
More worryingly, almost one in five (19.5%) of infected people who had an underlying condition died. Only 1.6% of infected people without an underlying condition died.
This clearly means that reasonably healthy people, with no major co-morbidities, have a good chance of outlasting the coronavirus disease, although actuaries would still describe a 1.6% fatality rate as too high (at the level of the population, it is).