We’ve seen a bit of caseload flattening in some of the south and southwest, but not in California or Monterey county. Here’s a composite view, normalized for population:
Here are the individual plots:
I’ve had some people tell me that the increase in cases is entirely the result of increases in testing. A standard way to look at that is the positivity ratio, which is the number of positive results over the number of tests. I don’t have stats for the country as a whole, but that ratio is rising in both Monterey County and California:
The above has a logarithmic y-axis to separate the low positivity ratios. You can see that the 7-day moving average has quadrupled since late May.
In California as a whole, the positivity ratio has about doubled in the same time period. That indicates to me that we don’t have enough testing. However, I should note that the positivity ratio can be affected by testing policy. In light of the recent surge in cases, the stat of California is restricting testing to people with symptoms, their close contacts, and those whose work exposes them to Covid-19 patients. Leaving out the people who are merely curious will raise the positivity rate. Emphasizing testing of symptomatic patients will do the same. Emphasis on screening of health care workers who are in contact with Covid-19 patients will probably lower the ratio.
The same people who are saying that the rise in cases is purely the result of increased testing say that there has been no increase in hospitalizations or deaths. In the case of hospitalizations, the premise isn’t true, at least in Monterey County and in the state of California.
Confirmed hospitalizations means hospitalizations of a patient who has tested positive. Suspected hospitalizations means hospitalizations of a patient who has not tested positive, or has not been tested at all. In California, tests have begun to take longer to be processed than three of four weeks ago. That may explain the rise in suspected hospitalizations that we’re seeing. In Monterey County, the average turnaround time for testing is running a bit under 3 days, which is better than in some parts of the state.
I haven’t been tracking Monterey County hospitalizations because the sample set is so small, but we are beginning to run up against the limits of current capacity in Salinas.
One way to get a handle on the relationship between number of tests and positivity ratio is to plot the two against each other:
It appears that doing more testing lowers the positivity ratio. However, there’s a caveat here. The data plotted above is for the stat of California as a whole, and in that state, the number of tests has been more or less steadily rising with time, so the higher you go on the x-axis, the later the point is likely to be.
Deaths tend to lag cases by more than hospitalizations. In the country as a whole, deaths are not rising much:
But in California we are beginning to se what could turn out to be a dramatic increase:
Thanks for detailed analysis.
It is excellent when fatality rate is going down. It may seems that the infection rate goes down in the most vulnerable groups. Another factor is that basic understanding of Covid 19 is better, so treatment is better, avoiding intensive care or worse.
Here in Sweden we have seen a strong correlation between fatality and elderly care. Those numbers were reduced due to efforts in basal hygiene and reducing spread.
One consideration I may have that health care may be a source of spread. Lot’s of infections within a small locale. Added the possibility that some of the spread is aerosol based. Also, health care personnel also have a live in the other (normal) world and they certainly deserve it.
For some reasons, infection rate and positivity ratio are going down in Sweden, all of sudden. Perhaps people living more outdoors?
People in California tend to be outside quite a lot given the favorable warm weather and climate. It is very densely populated however and people are very social. The geography also facilitates lots of travel and cross pollination amongst the population. I live in a less populated northern state with relatively cooler weather but more mountainous and rural and out numbers have been going straight down all throughout the re-opening.