What Does the Difference in the Covid-19 Stats Mean?

For the record, I am not a statistician.  I am not a medical professional.  To say that my science background is limited would be an understatement.  I'm doing basic math; whether the suppositions behind that math have any merit is for you to decide. 

I've been tracking the numbers on Covid-19 via NOLA.com, and then I've been crunching the numbers to give them more perspective.  I started doing this in May, and without far more work than I'm willing to do (and maybe even if I tried) I can't go back and find some of the numbers before then.  I've recently started saving daily charts and numbers so maybe I can dig up more information in the future, but I digress.

In the middle of June I started noticing that the proportion of cases in each age group were changing.  You can read my other posts to follow them, but for context, here are the cumulative numbers for June 7:

Kids now make up 3% of the diagnosed cases and 0.07% of the deaths.  Of the diagnosed kids, 0.15% have died.

14.5% of diagnosed cases are in 20-somethings, but only 0.35%  of the deaths.  Of those diagnosed, 0.16% have died.

16.07% of diagnosed cases have been to those in their 30's.  1.73% of the dead were in their 30's and of those who tested positive, 0.71% have died.

16.48% of people testing positive were in their 40's, but only 3.68% of the dead. Of those who tested positive, 1.47%  have died.

17.6% of positive tests were to those in their 50's; but 8.74% of  the deaths. 3.08% of  the diagnosed have died.

14.85% of cases were people in their 60's, and 18.08% of the dead.  8.03% of those who tested positive died.

17.08 % of positive tests were to the elderly, and they comprise 67.39% of the dead. 26.03% of those who tested positive have died.

Compare those numbers to the numbers for today only.  Today we had 1936 new cases and 23 deaths, distributed as follows:

Under 18:  157 cases or 8.1% of cases.  No deaths. 

20's:  531 cases or 27.4% of cases.  No deaths. 

30's:  300 cases or 15.49% of cases.  1 death, or 4.34% of deaths

40's:  264 cases or 13.63% of cases.  1 death or 4.43% of deaths

50's:  283 cases or 14.61% of cases.  5 deaths, or 21.73% of deaths

60's:  140 cases or 7.23% of cases.  5 deaths or 21.73% of deaths. 

70's:  261 cases or 13.48% of cases. 11 deaths or 47.82% of deaths.

I don't know enough about statistics to know if the different proportions of the dead between today and the whole time through June 7 is significant.  I realize that one day can be an outlier. 

Let's take a look at the total numbers since this started, as of today.  If nothing had changed, these numbers should be close to what is above:

Under 18:  4095 cases or 5.99% of positive tests.  3 deaths or 0.09% of deaths.  Of those diagnosed, 0.07% died. 

20's:  14383 cases or 21.06% of positive tests.  11 deaths or 0.34% of deaths.  Of those diagnosed, 0.07% died. 

30's 11,098 cases or 16.25% of positive tests.  57 deaths or 1.77% of deaths.  Of those diagnosed, 0.51% died. 

40's:  10,490 cases or 15.36% of positive tests.  111 deaths or 3.45% of deaths.  Of those diagnosed, 1.05% died. 

50's:  10,417 cases or 15.26% of positive tests.  280 deaths or 8.72% of deaths. Of those diagnosed, 2.69% died. 

60's:  8331 cases or 12.20% of positive tests.  571 deaths or 17.78% of deaths.  Of those diagnosed, 6.85% have died.

70's and older:  9295 cases or 13.62% of positive tests.  2178 deaths or 67.82% of deaths. Of those diagnosed, 23.43% have died.

When I looked at these numbers on June 28, I remarked that I was surprised that the last number on each row, the percent of the diagnosed who die, had not really moved  in the six weeks I had been tracking the numbers.  Well, it has started to move.  If you compare The June 7 numbers to the cumulative numbers I computed today, you can see that a lower percent of people in each age group who are diagnosed are dying.  I don't know to what extent this is attributable to better treatment and to what extent it is attributable to people who are less sick (or maybe not even sick at all) being tested and found positive, as compared to those in March and April.  

We have gone, in the space of a month, from a disease that mostly attacked old people to one that is getting the young.  As of June 7, 17.5% of the diagnosed people were under 30.  Today 35.5% of those added were under 30, and the cumulative total is now 27% under 30.  As of June 7, 17.08% of the cases were in the elderly.  Today only 13.48% of positives were elderly and cumulatively, only 13.62%. The age group with the big difference is the 50's. On June 7, they were 17.6% of positives, today 14.6 and cumulatively, they are down to 15.26%.  

Our hospitalization numbers are now back where they were on May 18.  There was about a week between peak hospitalization in April and peak death in April. It will be interesting to see if the number of deaths starts increasing again or if it stays low.  Also we have been under a mask edict since July 1.  It seems that if masks are effective we should start seeing a downward trend in diagnoses starting about now.  On the other hand, it is possible that masks make people feel safer such that they take bigger risks than they had been taking.  Who knows?