Some unconnected observations.
As expected, the hospitalization rates are increasing in those states that opened a month ago. There has been the anticipated lag, and now the slope of those increases has begun to parallel the identified case increase.
Deaths have begun to follow the hospitalization rates, again, totally as expected with the concomitant lag. Death rates can be expected to be below those seen during March and April because of several when we are testing people with less severe symptoms.
- Also, medical protocols for treatment of patients have evolved as we have learned more including high volume oxygen treatments in place of early use of ventilators, the use of Remdesivir and steroids to reduce inflammation and treat the virus directly.
- And finally, the current increases in infection, having been triggered by impatient reopening has skewed infections towards a younger cohort who, although still potentially vulnerable to lethality, have a far lower mortality than earlier, older populations.
There is effectively no data suggesting that the decrease in death rate is due to some change in the virus itself. The death rate decrease is easily understood by the effects listed above.
One of the interesting differences between COVID-19 and influenza is that with COVID-19, viral shedding occurs in the throat and upper sections of the respiratory system, while in influenza, viral shedding occurs much deeper in the respiratory system. The net result is that with COVID-19 the path for the virus from the infected body to the outside is shorter and easier. This may be one explanation about why COVID-19 is so much more transmissible than flu.
The misnomer of “asymptomatic.”
We want to be able to hold onto the fact that as many as 80% of individuals who are tests are “asymptomatic”. We make the unfortunate intellectual jump, from “asymptomatic” to “disease-free”. This is absolutely wrong; let’s see why.
Let’s say you test 300 people. 100 come back positive. Of those 100, only factors previously discussed.
- Previous testing was restricted only to those patients presenting at hospitals with significant disease, so the likelihood of them having fatal consequences would necessarily be significantly higher than now
20% are currently showing symptoms, so we say that the balance, or 80% are “asymptomatic.” Factually, this is true, but it is very important to look inside the number.
Of those 80 asymptomatic people, about 40 of them are actually “pre-symptomatic”, i.e., the incubation period of this disease is anywhere form 5-14 days, meaning that someone who shows no signs but tests positive will quite likely develop disease within the next couple of weeks.
Of the remaining 40 who do not develop symptomatic disease, about 20 will show lung involvement if a CAT scan is performed. These “walking pneumonia” like diseases are people who are fully functional even though there is internal involvement of which they are unaware. At this point the optimistic medical prognosis for these patients is that they will recover, and the lung damage will reverse. However, we are still early on in this disease and long-term effects are not understood.
Bottom line: The 80% “asymptomatic” group of positive tested individuals is more likely between 15-40% disease free.
Of course, we all understand that asymptomatic, pre-symptomatic and all other positively-tested individuals can transmit the disease.
An interesting study this week looked at children and adults in regard to virus shedding. Although, in most (but not all) cases, young children are not seriously affected by COVID-19, this study showed that the amount of virus shed from a child is equal to the amount of virus shed by an adult.
When considering opening schools, we need to keep in mind that although infected children will have a low lethality index, their transmissibility index will be equal to adults. Your chance of being infected by being too close to an infected child is the same as your chance of being infected by being too close to an infected spring-breaker or bar hopper.