What to we know about COVID-19?

My answer in Quora.

A lot more than we did at the beginning of the year. The challenge here has always been to separate the fact from both the myth and the all too obvious misdirection of the political narrative. I have put together a list of several big ticket items that I believe are worth knowing about the virus and the pandemic in general. I have cross-referenced the sources. This is by no means all inclusive but I believe it to be helpful.

New Coronavirus Source: dailynews.mcmaster.ca

• The virus seems to have originated in a wet market in Wuhan , China in December 2019 (possibly earlier). The common belief is that this RNA virus has a history of incubating in bats, likely jumped into an intermediate species (once thought to be Pagolins although this does not seem to be the case) before moving into the human population. An alternative account is that the virus may have leaked from a virology research facility in Wuhan. It does not appear to be genetically engineered although there are some dissenting opinions on the issue. (1,5)
• It was officially first identified as a novel (ie. new) coronavirus on the 31st of December 2029. Although the real identification likely happened way earlier. (1,29)
• The initial global response to the virus was poor. This seems to be a function of cover-up by the Chinese Communist government and mishandling by the WHO. Its spread was grossly underestimated on many fronts. It took a while for China and the WHO to admit that human-to-human contact spreads the virus. The WHO was also late in declaring the Virus to be a pandemic. Early international travel spread the virus to hotspots such as Northern Italy. Mask usage in the west was only reluctantly embraced. The CDC acting on WHO information were also slow in response to the virus. (2,3,4)

Chinese whistleblower doctor - Li Wenliang source; BBC News

• The official name of the virus is SARS-COV-2. It belongs to the coronavirus family (corona means crown - the virus has a crown-like structure) and falls into the same grouping as the Common Cold, SARS and MERS. It is a RNA virus. It needs an animal cell to replicate but does not need to penetrate the host cell nucleus.Replication occurs in the cytoplasm and the host cell is often destroyed. Dead viral particles can linger for several months after infection. (6,8)

Source: talk.ictvonline.org

• The virus latches onto the ACE-2 receptors on cell which it uses to gain entry into the cell. ACE-2 receptors are common in the respiratory tract of humans. However they exist in our gastro-intestinal system as well which explains why diarrhea can sometimes be a disease symptom..(7)

The Virus and the ACE-2 Receptor - a match made in hell. Source: rndystems.org

• The symptoms exhibited by the infected are very similar to those shown by suffers of the flu however the lethality of the disease is significantly higher in the population as a whole. Although not so far those below age 40. (9)
• Influenza outbreaks roughly have a lethality of 0.1%. COVID-19 (the name of the disease…19 refers to 2019) has a lethality rate somewhere between 0.4–1.2% based on Antibody tests. The average seems to be around 0.7%. The antibody test is a serological test that looks for Immunoglobulins (IgG) made in response to the virus. Most diagnosis for COVID-19 though is carried out following a PCR antigen swab. (10,11,24,25)
• The virus is most deadly in elderly populations with poor outcomes often been linked to various comorbdities viz. hypertension, diabetes and cardiac issues. Both men and women are infected equally but the death rate in men seems to be higher than women. Scientists are not exactly sure why that is the case. (12)
• Comparatively speaking very few children or individuals less than 40 have died from this virus however there have been some tragic cases.This differs from the Spanish Flu pandemic where twenty somethings were disproportionately hit. (12)
• At present we have no vaccines for the virus but there are several dozen teams working across the planet that are in the process of developing one. The lead candidate looks to be the Oxford University team (although they had a setback recently in trials). Optimists believe that a vaccine may be ready in September but in reality we are looking more at an early 2021 time frame. (13)
• Several therapeutics offer hope but a great deal of the evidence presented so far is either anecdotal or in-vitro based. Many repurposed drugs such as Remdesivir offer hope. This is an ongoing research initiative. Monoclonal antibodies do seem promising. (14,15)
• Officially there are almost 5 million cases worldwide but this may be an underestimate of the true number by an order of magnitude of ten.. The death rate sits at 324.000. Both values are likely heavily unreported across the globe. There is a belief though that death numbers in the West may be overstated as it is not easy to discern which patients died of another cause while testing positive with COVID-19 and which patients died as a consequence of COVID-19. (16)
• One of the biggest problems with this virus is that a great deal of those who become infected are asymptomatic. Estimates as high as 80–90% have been given for those that fall into this category. These individuals shed the virus but don’t demonstrate the usual symptoms associated with the disease. They can infect others. It is this group that generally does not report to COVID-19 assessment centers. After all why would they? (17,18)
• For those who eventually become symptomatic the time frame of the disease reads as follows…0–5 days (no symptoms), 5–12 days (symptoms…..viral shedding..very infectious). Those taking a bad turn normally do so in around Day 10. Full incubation is 14 days (or more) to fully bracket the 12 day window, There is some variability around these numbers. (21)
• The principle reason for many of the bad turns (associated but not restricted to the vulnerable demographics) is a cytokine storm where the immune system overreacts to the antigen causing fluid build up around the alveoli in the lungs. Situation worsens as a result of inflammation and coagulation (19, 20)

The Cytokine storm (no unusual in influenza).source: nature

• It appears that you can’t catch the virus twice. This was a concern about six weeks ago. The primary means of transmission is through human-to-human contact via aerosol and water droplets that are expelled by an infected person in close distance to another. This rationale drives the policies of social distancing and mask wearing. (22,23)
• Estimates vary as to what the viral R0 (R nought or naught) is. This is a measure of the average number of people who pick up the infection from a contaminated individual. An R0 below 1.0 generally bodes well in an epidemic/pandemic. Common wisdom is that a maintained R0 below 1.0 will cause the disease to eventually die out. There is some debate though as the usefulness of this metric. (26)
• There seems to be multiple viral strains but the virus itself has a low mutation rate that should prove helpful in vaccine development (27,28)

NOTE - I will probably update this answer as New Information becomes available.

Sources:

1. WHO Timeline - COVID-19
2. China’s COVID-19 disinformation push, aided by Canadian group, raises concerns about next pandemic
3. Coronavirus Crisis Shows China’s Governance Failure
4. Anger erupts after virus whistleblower doctor dies
5. SARS-CoV-2: an Emerging Coronavirus that Causes a Global Threat
6. SARS-CoV-2 is an appropriate name for the new coronavirus
7. How Coronaviruses Cause Infection—from Colds to Deadly Pneumonia
8. The Baltimore Classification System
9. Coronavirus Age, Sex, Demographics (COVID-19)
10. 1 in 5 people tested in New York City had antibodies for the coronavirus
11. Dutch study suggests 3% of population may have coronavirus antibodies
12. Coronavirus COVID-19 (SARS-CoV-2) | Johns Hopkins ABX Guide
13. U.S. commits $1.2 billion to production of Oxford coronavirus vaccine
14. Drug inspired by an old treatment could be the 'next big thing for Covid-19'
15. How Remdesivir Moved From Back Shelf to Best Hope for Treating COVID-19
16. Coronavirus Update (Live): 5,165,782 Cases and 332,808 Deaths from COVID-19 Virus Pandemic
17. Two-thirds of Covid-19 cases may be undiagnosed
18. Testing Reveals 'Stunning' Asymptomatic Coronavirus Spread Among Boston's Homeless
19. This is Why Some Patients Get so Sick With COVID-19 and Others Don't
20. COVID-19 cytokine storm: the interplay between inflammation and coagulation
21. Coronavirus Incubation Period (COVID-19)
22. Coronavirus: Scientists conclude people cannot be infected twice
23. How are people being infected with COVID-19?
24. Q&A: Influenza and COVID-19 - similarities and differences
25. Spanish antibody study suggests 5% of population affected by coronavirus
26. Coronavirus: is the R number still useful?
27. A mutated coronavirus strain seems responsible for most of the world's COVID-19 infections. That doesn't mean it's more dangerous than the original.
28. Coronavirus seems to mutate much slower than seasonal flu
29. First Covid-19 case happened in November, China government records show - report