Many are trying to explain the declining mortality rate, esp in the 2nd wave of countries like Spain 🇪🇸 , France 🇫🇷 and Italy 🇮🇹. Some suggested Memory T-cells from prior infections. The most logical explanation is weather / Climate / Summer. Here are some thoughts with ref. 1/ 
The Drop in COVID-19 deaths must be at least partially related to weather. Early on, many suspected a role for climate contributing to overall impact of COVID-19 pandemic, but continued spread around the world in May & June, even in warmer and humid countries, dampened that hope
Here are thoughts on why I think it’s real and playing out as we speak:
3 days ago during my daily review of cases/, I saw an unusual drop in most countries around the world. First I thought it was a fluke, but the trend continued. This is on the backdrop of a falling CFR
3 days ago during my daily review of cases/, I saw an unusual drop in most countries around the world. First I thought it was a fluke, but the trend continued. This is on the backdrop of a falling CFR
The worldwide drop in deaths simultaneously can’t be explained by local factors, such as each country’s place on the pandemic-spread curve, containment/mitigation measures, human behavior, testing, or treatment. /4
We know for a fact the strong seasonality of the 4 ‘Seasonal’ Coronaviruses with August being the lowest point in spread and illness.
In SARS-CoV-1: 1st index case: November 16,2002 and mysteriously ended worldwide around June-July 2003. /5
In SARS-CoV-1: 1st index case: November 16,2002 and mysteriously ended worldwide around June-July 2003. /5
There was strong suspicion that weather played an important role in that termination. SARS-COV-1 and 2 are very similar, so plausible. Paradoxically SARS-CoV2 is more dangerous than the 1st because it’s less severe i.e. less symptomatic so much more spread = more total deaths /6
jamanetwork.com/journals/jaman… We know for a fact that SARS-CoV2 thrives and lives much longer and more transmissible in cold and dry environment. Even when it spreads in warmer and more humid weather, it might be less virulent, hence less COVID-19 severity. /7
theconversation.com/research-shows…
There is a propensity for respiratory viral infections to cause more illness in winter time. This is due to factors related to the virus itself or host factors. +/- effects of solar radiation +in extreme hot humid weath people congregate in AC rooms /8
There is a propensity for respiratory viral infections to cause more illness in winter time. This is due to factors related to the virus itself or host factors. +/- effects of solar radiation +in extreme hot humid weath people congregate in AC rooms /8
The virus can still spread during summer but might cause less severe illness. We don’t usually test on mass scale like we do now. I think this better explains the recent drop in mortality rate worldwide despite increasing cases. Can’t explain solely by an increase in testing. /9
This is a much more plausible explanation than attributing a more benign second wave in some countries to previous Memory T-cell / prior immunity. I think time will show that this is the most logical explanation for the low death rates occurring worldwide.
Gompertz curve doesn’t predict the outcome or peak, but once on the decelerating part, it predicts slow decay, which is different from the fast accel. at the start, in distinction with the usual mathematically predicted symmetrical sigmoid. In that sense Gompertz is better /10
Some are suggesting the drop in mortality as the natural burnout predicted by this equation, but the Gompertz function can only be accurate if no other confounding variables. It wouldn’t explain the drop across the world /11
Needless to say there are many other factors that can affect the trajectory of outcome in each country including: demographics, number of people already infected, measures taken to control the spread etc... /12
When trying to look at the Southern Hemisphere for parallels, remember that winter in the south is overall milder than the northern hemisphere because of the presence of oceans that buffer the climate. /13
If I had to guess, I would say death rates keep dropping in September, but might have another peak Dec 2000- March 2021, hopefully a milder one, or at least we’d be more prepared and know how to manage it. Not holding by breath for a vaccine /14
Since it’s a new virus with little prior specific immunity for most, and a tremendous ability to spread, we shouldn’t expect a dramatic stop of cases or deaths, since many factors can also play a role eg control measures, human behavior, viral load, host immunity, age etc /15
The response will not be binary, that is either large spread or none at all. It is a balance of forces that drive the spread and death rate, versus forces that counteract this. Weather is one of them.
Any thoughts welcome medicalnewstoday.com/articles/how-d…
Any thoughts welcome medicalnewstoday.com/articles/how-d…
SARS-CoV1 spread, peak and disappearance, notice the months. Again, unfortunately COVID-19 not going anywhere, is here to stay and likely become another seasonal Corona. We won’t notice it much better most will be immune. End
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