Please have a look at:

https://www.nature.com/articles/s41591-020-0820-9

"Rain falls at all the places, but it is the landscape which decides where the water is going to collect."

It is SARS-CoV-2 verses the immune response of the patient. Younger age patients have a strong immune system and usually are surviving, while those in older age group (with immunosenescence), patients with cancer or on immunosuppressants, and those with less resources to fight due to comorbidities have a bad outcome.

"This Coronavirus (SARS-Cov-2) has not read Medicine!" as has many other diseases.

Article The Rise of New Coronavirus Infection (COVID-19): A Recent Update

Good question. Apparently, this process has already begun. The justification for this thesis are data indicating slightly different responses and symptoms that occur in people undergoing severe Covid-19 disease in different climatic zones, in different living conditions, with different social characteristics, collective natural resistance to the SARS-CoV-2 Coronavirus etc. In this way, in the future, different mutated strains of Coronavirus can arise in different communities, in different countries, on different continents if there are no interpersonal contacts between different communities. It is rather unlikely if international tourism returns to normal, i.e. to the pre-pandemic state of the SARS-CoV-2 Coronavirus (causing Covid-19).

Greetings,

Dariusz Prokopowicz

Under 0.5 micron particle will go right to the end. SARS CoV2 is about 0.125 micron though it needs a vector. So we can calculate rest of the size. Fine pollution (under 2.5 micron which inculdes under 0.5!) of cities probably will help this virus journey right to alveolar space. Is this why more severe pulmonary problem in cities? Numbers suggest that