Update 14 July 2020: for the week ending July 11th, there were 5,085 new deaths, and 419,876 new cases, as weekly totals. Compare this to the week ending April 18th, almost 3 months earlier, with 18,437 new deaths and 205,913 new cases, also as weekly totals. Weekly deaths are down by more than two-thirds, while at the same time weekly new cases have more than doubled.


When a person is infected with the SARS-CoV-2 virus (the Coronavirus), it takes an average of 5.1 days before they show symptoms and therefore know to seek treatment at a hospital [1]. Then, in cases where death does occur, the length of time from infection to death in most cases is 20 days or less [2]. So the time from symptoms to death, if the patient does die, is usually 15 days or less. This information is useful because it tells us that, after an increase in new reported cases, we can expect an increase in deaths within about two weeks.

I say “two weeks” rather than 15 days because the timing is approximate, but also because when the case rate is flat, there will nevertheless be increases and decreases in daily cases due to a day-of-the-week phenomenon. In the United States, from mid-March when the case and death rates reached substantial daily numbers, Sunday and Monday have always been lows for the week, whereas the highs for the week have typically been Friday and Saturday, with occasional one-day highs anywhere from Tuesday all the way through to Saturday. Comparing the total new cases for Friday plus Saturday divided by the total new cases for Sunday plus Monday always gives us over 100%. This means that Friday and Saturday have more new cases reported than Sunday and Monday, even when the number of weekly cases is on the rise, on the decline, or flat.

We can speculate the reasons for this “day of the week” effect. It may be related to whether people who have symptoms will be more or less likely to go to the hospital on particular days. It may also be that reporting on Friday and Saturday catches up with some cases that actually came in a day or two earlier, and were not reported until the end of the week. Similarly, new cases on Sunday or Monday might be delayed a day or two in reporting. But the reason for the effect is not so important. We simply want to nullify this day-of-the-week effect so it does not mislead us when examining trends in new cases and new deaths. That is why data will be analyzed in this article by weekly totals, or by same day of the week to same day of the week.

Rise in New Cases

The week ending June 13th saw a total of 153,680 new Covid cases. Two weeks later the weekly new cases total was 265,959. A week after that, the week ending July 4th, it was 339,233 new cases — more than double three weeks earlier. But new deaths has not increased proportionately. The new deaths totals for those weeks were 5,431 deaths against 153,680 cases, and then 3 weeks later 4,166 new deaths against 339,233 new cases. Good news, or not?

Let’s look at different ways to calculate the death rate. Total cases to total deaths as of June 13th was 5.49%. A week later it was 5.23%, and a week later it was 4.94%, finally, yesterday (July 4th) it was 4.51%. The death rate is falling. And that’s a cumulative total of deaths and of cases. If we look at the weekly totals of deaths and cases, those four weeks are 3.53% of cases resulted in death, 2.36% the next week, 2.32% the week ending June 27th, and finally 1.23% for the week ending July 4th.

However, those stats are misleading, due to the 15 day lag from new cases to new deaths. So what we need to compare is weekly new cases against weekly new deaths from a couple of weeks later (14 days instead of 15 days, as previously explained). Now let’s put the lag into the calculations.

Note: after publishing this article, I came across a news article considering the same type of lag phenomenon: COVID-19 Cases Are Rising, So Why Are Deaths Flatlining? There is also a graphic showing the 14 day lag (which can be a little longer due to delays in reporting deaths).

One week after June 13th, for the week ending June 20th, the new cases increased 22.6%. Two weeks later, that 22.6% increase in cases did not result in a 22.6% increase in deaths, but in a 6.4% decrease in deaths. But a bigger jump in weekly new cases occurred from June 20th to June 27th, a 41.2% increase. Two weeks later is Saturday, July 11th. If we do not see a corresponding jump in weekly new deaths by then, we are in the clear. It will mean that there has been a real drop in the death rate. From the data so far, that seems to be the case. But we have to wait until two weeks after the very recent and rather large jump in new cases.

Regardless of how those numbers turn out, we are already seeing a decrease in the death rate comparing new cases to the new deaths with a two-week delay. That death rate has decreased from nearly 7% to just over 2%. Specifically, if you entered the hospital with Covid-19 on April 11th, your chances of death were about 6.88%. That figure is arrived at by dividing the weekly new deaths two weeks later (accounting for the lag) by the weekly new cases that previous week. But if you entered the hospital June 20th, just over two months later, your chances of death may have been around 2.21%. This calculation looks at weekly new cases and compares them to weekly new deaths two weeks later. Based on these calculations, the chances of dying from Covid-19 in early April were more than three times higher than in late June.

There are some reasonable assumptions in this calculation. But it is undeniable that the death rate is falling. We will know with greater certitude over the next week. If the death rate does not rise considerably by July 11th, we will have seen the death rate drop to one third — not by one third, to one third. That’s a 67.8% drop in the death rate.

Update July 11th, 2020: the new case rate has increased greatly, but the death rate is still falling. July 10th had over 71,000 new cases and only 863 new deaths for the same day. Comparing that week’s new deaths to new cases from two weeks earlier gives us a death rate of just under 2% (assuming Saturday’s new deaths are about the same as Friday’s).

Compare this rate to the rate for the week of new deaths ending April 11th, against new cases from 2 weeks earlier, when the death rate was 12.2%. Clearly, the death rate is falling dramatically. If the death rate today were 12.2%, 71,000 new cases per day would imply over 8,600 new deaths per day. Instead, the new deaths was a tenth of that figure (863).

What is the Cause?

Now for the bad news. The drop in the death rate is mostly likely due to one of two causes. Either doctors and hospitals have improved their treatment regimens of patients so much that the death rate dropped by two thirds, or we are seeing a common effect found in contagious respiratory ailments, an improvement in summer and a worsening in winter. Some diseases, like the version of coronaviruses that cause colds, are seasonal. And they diminish in case rate and in severity in summer, and increase conversely in winter.

I’m following the research on Covid-19 closely. I read new studies on a near-daily basis. I’m reading what doctors with Covid-19 patients are saying about treatments. And they really do not have a treatment that simply works, as in: you give it to the patient, and they just get better. Not at all. Not yet. The treatment regimens are slowly improving. But since we don’t have a single clear effective treatment, I can’t believe that the 2/3rds drop in the death rate is due to improving treatments. Some of the drop is certainly from that cause, but not most of it.

The reason for the drop is probably because Covid-19 is seasonal. See this article and the studies it cites. Vitamin D has a large influence on whether people contract Covid-19, and on how serious the disease may be, according to 14 vitamin D studies so far: Listed Here.

And that is bad news because, if the drop in the death rate is mostly due to higher vitamin D levels in summer, the death rate will rise sharply as winter approaches. Vitamin D is made when UV light from the sun strikes the skin. But in the winter, people are indoors more and the sun is also lower in the sky. This results in a cycling of vitamin D levels, lower in winter and higher in summer. We are seeing the benefits of that now, but the detriments will begin in October, and increase again in November, and again in December. That is the pattern for vitamin D levels and for seasonal illnesses.

The death rate could fall below 2% by September. But by December, it could be as high as 6 to 7% (or more). So the good news of a drop in the death rate has, well, whatever the opposite of a silver lining would be. This dire prediction could be averted by an extensive vitamin D supplementation program, so that vitamin D levels are raised in every population at risk of Covid-19. But the way our society works today, I don’t know if we can convince enough persons to support and to participate in such a program. And if that fails, this coming winter will be very harsh.

Ronald L. Conte Jr.
Note: the author of this article is not a doctor, nurse, or healthcare provider.

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1. Lauer, Stephen A., et al. “The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: estimation and application.” Annals of internal medicine 172.9 (2020): 577-582.

2. Kobayashi, Tetsuro, et al. “Communicating the risk of death from novel coronavirus disease (COVID-19).” (2020): 580.