Dear Dr. in this RE open question we attempt to analyse the Lombardia dramatic event in mortality rate, but now, also for other Europea key areas (Madrid, Catalonia, London, Netherlands). Some work hypothesis are: oro-fecal transmission; Diamond Princess passengers return as spreaders (according to insufficient quarantine and positive intestinal tests but negative in nasal-oral tests); additional animal reservoirs; urban-river effect.

https://www.researchgate.net/post/The_novel_Coronavirus_in_N_Italy_Lombardia_COVID19_2019nCoV_SARSCoV2_shows_a_fatality_rate_compatible_with_SARS_Why2

Dmitry Nikolaenko can you please stop spamming questions with your preprint, especially when it does not address the question in hand.

If you want to get people involved in your work open your own discussion on Researchgate please.

Transmission rate (described as Ro) was initially estimated to be 2, now it is above 3.

On average all over the world (data on worldometers/coronavirus), taking known deaths and the total documented COVID-19 cases, mortality is around 5.85%. However, it is highly variable in different countries, with figures as low as 10% in Spain and Italy. Other countries are in between. The definitive mortality rate would be known, once the data is available at the end of pandemic.

https://www.worldometers.info/coronavirus/

(Calculate crude mortality rate by world data, and the mortality rate by individual country data. Transmission rate or R zero is given in the discussion at this site)

Dear Ashif Sajjad

For case fatality rates of different countries, ever changing almost every day, you can get the data from:

Global Covid-19 Case Fatality Rates - CEBM

https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/

The current estimates of numbers of COVID-19 cases and deaths are very inaccurate. The sensitivity and specificity of the diagnostic tests for COVID-19 are not yet known in vivo. There are reports of very high sensitivity and specificity in vitro. However a number of confounding factors (e.g. the stage of illness and the way the swab was taken) mean that the false negative rate of these tests may be high in clinical practice.

Wenling Wang; Yanli Xu; Ruqin Gao; et al Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Jama 2020 (in press).

The numbers of cases reported will also depend on strategies used for screening. Many countries are only screening symptomatic patients presenting to healthcare facilities. Others are attempting to screen a significant proportion of the population.

I believe the total number of cases of COVID-19 is significantly higher than that being reported. There are many confounding factors (both political and diagnostic) that make the initial number of deaths reported as being due to COVID-19 extremely difficult to interpret.

The availability of healthcare in general and specifically critical care will affect case fatality. In China and Italy where large numbers of healthcare professionals were infected the capacity to deliver healthcare was substantially reduced.

Another important factor to consider when trying to interpret variation in mortality rates between countries is differences in cultural interpretation of quality of life. This impacts the social and medical ethics and the delivery, limitation and withdrawal of life sustaining therapies.

In many Western cultures quality of life is valued far more than quantity of life. In those settings limitation and even withdrawal of life sustaining therapies resulting in cardiac arrest are a common mode of death.

In many Eastern cultures quantity of life is valued more than quality of life. In these settings treatment limitations and withdrawals of therapy are rare. Admission to intensive therapy units and prolonged organ support are common. Mode of death is often failure of resuscitation after cardiac arrest.

These differences are magnified when there are limited resources particularly in Western countries. The social and medical acceptance of treatment limitations is increased; this may significantly increase case fatality rates.

An unfortunate adverse effect of social distancing for the Covid-19 pandemic has arisen. There has been a dramatic fall in the number of blood donors in Saudi Arabia a result of social isolation during the Covid-19 Pandemic. Supplies of blood are being depleted. This is likely to be a global phenomenon

If insufficient blood of the correct type is available a woman may die as a result of not being transfused blood for severe acute bleeding following delivery of a child, for example. This will be most challenging for patients with rare blood group

Patients may die as a result of not being transfused blood severe acute bleeding due to stress ulceration, for example. If the patient has severe or critical Covid-19, the cause of death is actually the Covid-19 but it is likely to be coded as GI tract bleeding.

See

https://www.researchgate.net/post/Measuring_mortality_rate_for_COVID-19

There is an indication that a genetic defect in some patients is responsible for some of the most severe effects of a Covid-19 infection. Some patients are experiencing what is commonly described in viral infections of this type as a cytokine storm which in effect means that their secondary immune response runs out of control causing potentially massive organ failure. 

The genetic defect results in an instability in the human IFN-beta gene responsible for the production and synthesis of interferon, which is in effect the first line of defence to a vial infection. The secondary immune response causing the cytokine storm is known to have been responsible for huge numbers of deaths in the 1918 H1N1 outbreak and the later avian flu H5N1 epidemic.

This defect is uncharted in the general population but a polymorphism such as this could be responsible for the variation in infections and fatalities.

The lethality rate varies greatly and is lower above the 40th parallel but also around the equator (it seems that the virus loves temperate climates and hates too dry and too humid)

Mauro Giovanni Carta Dear Professor, please note that Case Fatality Rate (CFR) and Mortality Rate (MR) are two diverse variables that refer to the number of deaths due to a specific disease. Which one were you referring to?

In addition, some of these variables can refer to distinct stages of the disease (e.g., pre-symptomatic, mild or severe clinical pictures).

In my opinion, only a part of these variables can be reliably calculated for COVID-19

Lethality stands for CFR, is an incidence rate, most relevant institutions are calculating it form 21 February. Sorry is above 50th North and under 40th South (i.e. Falklands). Now a new Work from Brazil found that the virus is much less aggressive above a temperature of 25.8

currently, global mortality is around 7%, but I have the impression that this data is highly underestimated

It is certainly underestimated. In Italy there is an excess of mortality in February March, compared to the previous 5 years which cannot be explained only with the proven Covids. For example in the Lombardy region the excess mortality compared to the previous 5 years, is 186% but only 30% can be explained with the official covid deaths.

Mortality due to COVID-19 is overestimated and depends on testing capability of a country, diagnostic labeling, and percentage of older population in a country.

It is lowest in Qatar and Singapore ( 14%).

Final mortality will be determined after the end of COVID-19 pandemic by calculating the excess mortality per year for the duration of the pandemic.