Vaccsbook

The COVID-19 virus pandemic began in late 2019 in Wuhan China and has spread to over 220 countries on all continents . . . including Antarctica.
(The U.N. recognizes a total of 251 countries.)

At the time of writing, the prognosis for the COVID-19 pandemic is uncertain.
Most countries are reporting that cases/deaths increase, subside, then increase again in "waves".
Vaccines have been authorized for emergency use, but their effectiveness is unestablished.
What follows may be outdated or superseeded within a few days. (Last updated November 2021)

Type of Infection

COVID-19 is a disease caused by a coronavirus called SARS-CoV-2. It was first identified late 2019 in Wuhan, China.
In 2020, the virus began to mutate resulting in several "Variants of Interest" (VOI). VOIs known to be more easily transmitted from person to person, and/or cause more severe disease are reclassified as "variants of concern" (VOC). The variants are usually referred to by the location where first discovered and/or an assigned "lineage" code.
As of November 2021, the most frequently diagnosed variants are:

Identified in	Lineage	W.H.O. label
Italy	B.1	n/a
UK	B.1.1.7	Alpha
South Africa	B.1.1.529	Omicron
South Africa	B.1.351	Beta
California	B.1.427/B.1.429	Epsilon
USA	B.1.525	Eta
USA	B.1.526	Iota
India	B.1.617.1	Kappa
India	B.1.617.2	Delta
Colombia	B.1.621	Mu
South Africa	C.1.2	(tba)
Peru	C.37	Lambda
Brazil/Japan	P.1	Gamma
Brazil	P.2	Zeta
Philippines	P.3	Theta

The effectiveness of each COVID-19 vaccine against each variant is still under intense investigation.

Also known as

SARS-CoV-2 pandemic, and Severe Acute Respiratory Syndrome Coronavirus 2.

Disease

Infection with COVID-19 can be asymptomatic, cause mild respiratory symptoms, or causes pneumonia and multi-system organ failure (MSOF) and be fatal.
It is belived that the virus enters the lungs by attaching to an "Angiotensin Converting Enzyme" (ACE) Receptor in lung cells. Many patients take medications called ACE-inhibitors to control blood pressure. In animal studies, ACE Inhibitors cause an increase the number of Receptors; some suggest this increases a patient's susceptibilty to COVID-19.
Alternatively, ACE Inhibitors occupy the receptors and may have a protective effect.

Vaccination

Vaccines have been developed and authorized for emergency use, mostly in devloped countries, click Vaccines for more details.
The long term effectiveness of each COVID-19 vaccine against each variant is still under intense investigation.

Acquisition & Transmission

The origin of COVID-19 is debatable.
Wuhan is the location of a bio-safety level 4 virology lab (BSL-4 is the most secure level). There is speculation that this lab does research on coronaviruses and that COVID-19 was created in this lab.
Others believe the viral genetics indicate it originated in bats or other animals such as the Pangolin (aka Scaly Anteater), and humans acquired it through contact at a Wuhan "wet market" where live animals were sold.
As yet, there is no convincing evidence for or against COVID-19 having an environmental vs. bioenginered origins.

When initially diagnosed outside of China, many countries stated there was no evidence of human-to-human transmission and cases were labelled "travel related" (implying everyone had been to the same wet market ?).
Human-to-human transmission through airborne respiratory droplets, created by an infected person coughing, sneezing, or talking, was soon established.
Moreover, even if an infected person appears well, transmission to others is still possible. Whether fully vaccinated people can still trasnmit to others is currently unknown.
Most "experts" now accept that the virus exists in aerosolized form, as airborne virions without encasing droplets.
The virus has been shown to survive on surfaces and objects for up to 72 hours; whether it can be acquired by touch to the nose and mouth in sufficient numbers to cause disease is unclear.

Signs and Symptoms

The majority of infected patients have very mild signs and symptoms or none at all, and COVID-19 is only detected in these by population-wide testing.
Signs are an elevated temperature of at least 38C. Symptoms are shortness of breath, muscle pain, cough, lethargy, sore throat, abdominal pain, and possibly loss of the sense of smell.

Timeline

Incubation, from time of exposure to the onset of symptoms, is about 5 days (range 2 to 14 days). Symptoms, when they occur, last 1 to 2 weeks in mild cases, but up to 6 weeks in severe cases. When death occurs, it can be from a few days to 8 weeks after the onset of symptoms.
Recovery may result in antibodies, as usually occurs following most other infectious diseases. However, at present it is unclear how effective these antibodies are in preventing re-infection or how long they last.

Contagion

COVID-19 is highly contagious.
Infected patients are probably contagious within a few days of exposure, then peaking about 3 days after the onset of symptoms. Many patients who are infected have mild or no symptoms, but can still pass the infection to others. Whether fully vaccinated people can still trasnmit to others is currently unknown.

Diagnosis

Diagnosis is made on the basis of symptoms, a history of contact with another infected person, chest x-ray or CT scan.
Testing on both symptomatic and asymptomatic people is by a specimen taken by swab from the nose/throat.
PCR (Polymerase Chain Reaction) tests are done in a laboratory and can detect disease at its very early stages.
Screening asymptomatic patients can be done by Rapid Antigen tests which give results in a few minutes. However, these tests often yield false negatives in the early stages of disease, and any positive test need to be confirmed by a PCR.

Body Systems Affected

COVID-19 primarily affects the lungs, causing a pneumonia that affects all lobes of the lungs (many pneumonias only affect 1 of the 5 lobes of the lungs).
In severe cases, an excessive response of the immune system leads to dysfunction of the liver, kidney, intestines and blood systems, which is fatal in approximately 50% of patients

Treatment

Treatment is supportive; intavenous fluids, oxygen, and intubation with mechanical ventilation when necessary. Antiviral medications are being evaluated worldwide, as are antibiotics usually used for malaria.

Prevention

Prevention consists of frequent hand-washing and maintaining 2 meters distance from all others, the use of personal protective equipment (PPE) by health care workers, and strict infection control practices.

Only specific medical grade masks can prevent the virus from being inhaled.
Paper/cloth masks intended to prevent asymptomatic persons from transmitting the virus to others have been widely recommended. In many jurisdictions, mask wearing was made mandatory in mid-2020, but daily case loads started to increase soon after and continue to recur in waves.
Prospective studies released in late 2020 suggest non-medical grade masks are ineffective in preventing spread of the virus; many have suggested they give a false sense of security and cause neglect of sensible prevention measures mentioned above.

Complications

Some patients who recover from the acute pneumonia under many months of generalized sysmptoms such as fatigue, headache, shortness of breath, joint and muscle pain, and memory/concentration/sleep deficits.
As previously mentioned, an excessive or dysfunctional response of the immune system can lead to dysfunction of the liver, kidney, intestines and blood systems (both abnormal clots in the circulation and bleeding), which is fatal in approximately 50% of patients.

Fatalities

The first fatalities occurred in China in November or December 2019.
The first fatalities in North America occurred in early March 2020.
By April 2020, 80,000 deaths had been recorded worldwide with 4,000 deaths occurring daily.
By May 2020, almost 300,000 deaths had been recorded with 2,500 deaths occurring daily.
By November 2020, 1,300,000 deaths had been recorded with 2,000 deaths s occurring daily.
By April 2021, 3,000,000 deaths had been recorded with 4,800 occuring daily, confirming the wave-like pattern of the pandemic.

The worst hit countries, with almost 1 death per 400 of the population, are in eastern Europe and the Balkan peninsula.
Brazil, Belgium, Spain, Italy, France, Portugal, USA, and UK have experienced 1 death per 500-600 of the population.
Germany, Greece, and Canada have experienced 1 death per 1,000-1,500 of the population.
Most African countries are reporting 1 death per 5,000-100,000 of the population suggesting incomplete data.

However, China, the origin of the virus, is only reporting 1 death per 300,000 of the population, raising suspicion about the accuracy of reporting.

Geography

Unlike SARS (2003), almost every country in the world has reported cases of COVID-19. In general, industrialized countries have the largest number of cases per capita, and highest death rate per capita.
Many African and Caribbean countries, and smaller island nations, appear less severely affected (subject to data recording inaccuracies).