Dear Reader:

I want to clean up my above post/ edit it so to correct mistakes:

The official name of the disease behind the current pandemic is COVID-19, an acronym for Coronavirus Disease- 2019 (I personally type “Covid-19”). The official name of the virus causing the disease is SARS-Cov-2, an acronym for Severe Acute Respiratory Disease Corona Virus 2.

There are currently 7 known coronaviruses that infect humans, all of them attack the respiratory system, a few are mild, others are severe. They differ in how contagious they are (their basic reproductive number, R0 is different. Ro is number indicating how many healthy individuals get infected by one infected individual, ex.:  An Ro of 2 indicates that one infected individual proceeds to infect two healthy individuals). Viruses also differ in how deadly they are (their mortality/ fatality rates are different).

The first two coronaviruses that attack humans  were discovered in the 1960s, and both cause the common cold (in combination with other viruses).

Another coronavirus (SARS-Cov) was discovered in 2003 in China, and it was responsible for the first SARS outbreak of 2002-2003– 8,422 cases, spread to 17 countries. The seventh known coronavirus (SARS-Cov-2) is responsible for the current, ongoing second SARS outbreak turned pandemic, December 2019- (?) over 16 million cases today, July 25, and growing.

SARS-Cov had a lower Ro and a higher mortality rate (11%) than the current SARS-Cov-2.

MERS-Cov is the coronavirus behind the Middle East Respiratory Syndrome (MERS)  outbreak of 2012 in the middle east, having spread to South Korea and a bit elsewhere, total under 2,000 cases.

MERS-Cov had a lower R0 than SARS-Cov-2, and a higher mortality rate (36%) than both SARS-Cov and SARS-Cov-2. But it was way less contagious than our current SARS-Cov-2, and therefore, the latter, over time, is more deadly.

Smallpox (Ro= 3.5-6), Mumps (Ro= 4-7), Rubella (Ro= 5-7), Polio (Ro= 5-7) and Measles (Ro 12-18) are all  more contagious than SARS-Cov-2 (Ro= 1.4-3.9). The reason for SAR-Cov-2 being as deadly as it is, is that too many people in different areas in the world were infected: more people die when a much higher number of people get infected with a lower R0 virus, than when a significantly lower number of people get infected with a higher R0 virus.

Another factor that influences how infectious a virus is- is the method by which it gets transferred from one individual to the next. Some viruses are transferred from one individual to the next by sexual intercourse. At any one time, only two people are engaged in sexual intercourse and people normally don’t have sexual intercourse all day and all night long. But at any one time, more than 2 people share the air, and we do breathe all day and all night long. (Also, t is possible to avoid sexual intercourse, but it is impossible to avoid breathing).

Of the viruses that are transferred through the air, those that are transferred in bigger droplets of liquid are less contagious than those transferred in very small droplets, aka airborne viruses, because bigger droplets respond to gravity and fall down way sooner than very small droplets that remain suspended in the air for a long, long time.

Regarding the viral diseases I mentioned above, those with high R0’s-  there are effective vaccines for all thee, but none yet for SARS-Cov-2.

-Summary and editing to continue later.

anita

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