COVID-19 is an acronym for Corona Virus Disease 2019. It is caused by the virus SARS-CoV-2, an acronym for Severe Acute Respiratory Syndrome Coronavirus 2. The common symptoms of COVID-19 are
- dry cough
- aches and pains
- sore throat
- loss of taste or smell
- a rash on skin, or discolouration of fingers or toes
A Virus outside the host body is just a particle made up of genetic material in the form of DNA or RNA encapsulated by lipid and protein layers.
There is no clear classification of Virus as living or non-living. Virus shows some attributes of living organisms while some attributes are missing. Particularly the behaviour of Virus outside the host body are that of a non-living organism. Like outside the host body the Virus can’t replicate neither its active nor depending on its surroundings for nutrients. It is really the behaviour of the Virus inside the host body that qualifies it as living. Inside a host body the Virus replicates and mutates to different forms.
Russian biologist Dmitri Ivanovsky in the year 1892 and Dutch microbiologist Martinus Beijerinck in the year 1898 are credited for the discovery of the first Virus, “Tobacco Mosaic Virus” using the technology invented by French microbiologist Charles Chamberland in the year 1884
As the name indicates, the TMV primarily infects the Tobacco plant leaves and causes discoloration in some areas of the leaves turning them into a mosaic like pattern. The TMV is a positive sense single stranded RNA.
RNA acronym for Ribonucleic Acid is a polymer ( Greek poly-, “many” + -mer, “part”) of nucleotides. Nucleotides are building blocks of Nucleic Acid or RNA. A nucleotide consists of a 5-carbon sugar molecule, a phosphate group and a nitrogenous base. The four bases used in nucleotide of RNA are Adenine (A), Cytosine (C), Guanine (G), and Uracil (U).
During protein synthesis process in cells the information in the DNA of the nucleus must travel to the protein synthesis sites of the cytoplasm and endoplasmic reticulum. The information in the DNA is transferred to a mRNA (messenger RNA) during transcription. This mRNA carries the genetic material or copy of the DNA which will in the end decide the protein synthesis from the cell. In short, the mRNA has message which can be directly used by the cell for protein synthesis.
Those type of viruses which carry a single stranded RNA as genetic material capable of acting like a mRNA and when these viruses enter a host body and the RNA from virus can directly be read by the host for protein synthesis are called as Positive Sense Virus. These viruses with positive sense are highly infectious as the protein synthesis in the host body need not wait for any other mechanism.
American biologist and Nobel Prize winner David Baltimore in the 1970s developed a method to classify Viruses based on the production method of mRNA.
SARS-CoV-2 (virus causing COVID-19) is a Baltimore class IV positive-sense single-stranded RNA virus(ssRNA) which is highly contagious to humans.
|Species:||Severe acute respiratory syndrome–related coronavirus|
|Strain:||Severe acute respiratory syndrome coronavirus 2|
SARS or respiratory diseases are usually caused by Coronaviruses and affects both humans and animals. Coronaviruses were first discovered in the year 1930 affecting domestic poultry. In the year 1965 first human coronavirus was discovered. So far 7 coronavirus affecting humans are discovered:
- 229E (alpha coronavirus)
- NL63 (alpha coronavirus)
- OC43 (beta coronavirus)
- HKU1 (beta coronavirus)
- MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
- SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS)
- SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19)
229E, NL63, OC43, and HKU1 infections are very common and the symptoms are flu and common cold.
SARS coronavirus (SARS-CoV) – virus identified in 2003. SARS-CoV is thought to be an animal virus from an as-yet-uncertain animal reservoir, perhaps bats, that spread to other animals (civet cats) and first infected humans in the Guangdong province of southern China in 2002. An epidemic of SARS affected 26 countries and resulted in more than 8000 cases in 2003.Implementation of appropriate infection control practices brought the global outbreak to an end.
|Country or region||Cases||Deaths||Fatality (%)|
MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (Middle East respiratory syndrome coronavirus, or MERS‐CoV) that was first identified in Saudi Arabia in the year 2012. The MERS coronavirus travels to humans from infected camels, the camels are infected by bats carrying the virus.
MERS has a very high mortality rate, out of 2519 cases 35 % people have died so far since 2012.
|Country or region||Cases||Deaths||Fatality|
|United Arab Emirates||74||10||0.14|
Other historic pandemics:
1918 H1N1 (Spanish flu): Killed around 50 million people worldwide
1957 H2N2 (Asian flu): Killed around 4 million people worldwide
1968 H3N2 (Hong Kong flu): Killed 1 million people worldwide
2005 H5N1 (Bird flu): Which mostly affected more birds and few human causalities
2009 H1N1 (Swine flu): Killed around 18,000 people worldwide
Structure of SARS-CoV-2
The coronavirus has four structural proteins, Nucleocapsid (N) protein, Membrane (M) protein, Spike (S) protein and Envelop (E) protein and several non-structural proteins. The capsid is the protein shell, inside the capsid, there is nuclear capsid or N-protein which is bound to the virus single positive strand RNA that allows the virus to hijack human cells and turn them into virus factories. The N protein coats the viral RNA genome which plays a vital role in its replication and transcription.
The coronavirus spike (S) protein attaches to angiotensin converting enzyme 2 (ACE2) receptors that is found on the surface of many human cells, including those in the lungs allowing virus entry. From there, the virus makes its way down into the air sacs inside your lungs, known as alveoli.
Once inside the body the viral proteins begin making copies of the viral genetic instructions and new viral proteins using the virus’s genetic instructions and the cell’s enzyme machinery. Once the new viruses are made, they leave the host cell by breaking the cell membrane destroying the host cell in the process. Sometimes the virus travel inside the membrane coat and hence the body takes time to detect the foreign body. Once the host body detects the pathogen, it releases pyrogens which increases the body temperature and hence the fever that follows the viral infection. SARS-Cov2 virus affects both the lower and upper respiratory tracts.
Phase -1: Early Infection
- Transmission: A healthy person inhales the virus through various means of transmission. The disease spreads primarily from person to person through small droplets from the nose or mouth, which are expelled when a person with COVID-19 coughs, sneezes, or speaks. These droplets are relatively heavy, do not travel far and quickly sink to the ground. People can catch COVID-19 if they breathe in these droplets from a person infected with the virus. Therefore, it is important to stay at least 1 meter) away from others. These droplets can land on objects and surfaces around the person such as tables, doorknobs and handrails. People can become infected by touching these objects or surfaces, then touching their eyes, nose or mouth. Therefore, it is important to wash your hands regularly with soap and water or clean with alcohol-based hand rub.
- Infection: The virus enters and attaches itself to the human body as explained earlier.
- Incubation: The virus keeps replicating inside the body without any signs like fever
- Body defence and symptoms: 14 days from infection the body will start producing antibodies and symptoms will start to appear. At this stage hospitalization and medical care would be required to mage symptoms like lack of oxygen in blood due to lung infections and lung’s ability to supply oxygenated blood to the body.
Phase-2: Pulmonary phase: Due to puss filled in the air sacs of the lungs pneumonia onsets and blood oxygen levels fall and patient may require external oxygen supply.
Phase 2A: Pneumonia without hypoxia (acute lack of oxygen in body parts)
Phase 2B: Pneumonia without hypoxia. Hypoxia can show symptoms like change in colour of skin, wheezing, sweating etc.
Phase-3: Hyperinflammation phase: During this phase there is total loss of blood oxygen and hence patients will need ventilator support
So far there is no approved drug for the treatment of COVID-19, however below drugs have been used worldwide with mixed results:
Dexamethasone is a corticosteroid used in a wide range of conditions for its anti-inflammatory and immunosuppressant effects.
It was tested in hospitalized patients with COVID-19 in the United Kingdom’s national clinical trial RECOVERY and was found to have benefits for critically ill patients.
According to preliminary findings shared with WHO (and now available as a preprint), for patients on ventilators, the treatment was shown to reduce mortality by about one third, and for patients requiring only oxygen, mortality was cut by about one fifth.
Chloroquine/Hydroxychloroquine and Azithromycin
Hydroxychloroquine and chloroquine have been shown to kill the COVID-19 virus in the laboratory dish. The drugs appear to work through two mechanisms. First, they make it harder for the virus to attach itself to the cell, inhibiting the virus from entering the cell and multiplying within it. Second, if the virus does manage to get inside the cell, the drugs kill it before it can multiply.
Azithromycin is never used for viral infections. However, this antibiotic does have some anti-inflammatory action. There has been speculation, though never proven, that azithromycin may help to dampen an overactive immune response to the COVID-19 infection.
Remdesivir is an investigational nucleotide analog with broad-spectrum antiviral activity – it is not approved anywhere globally for any use. Remdesivir has demonstrated in vitro and in vivo activity in animal models against the viral pathogens MERS and SARS, which are also coronaviruses and are structurally like COVID-19. The limited preclinical data on Remdesivir in MERS and SARS indicate that Remdesivir may have potential activity against COVID-19. Remdesivir is an experimental medicine that does not have established safety or efficacy for the treatment of any condition.
Drugs not so effective on COVID-19
Kaletra: A combination of lopinavir and ritonavir used as an antiviral drug for HIV patients has been proposed initially as a treatment of COVID-19. Later studies have proven that Kaletra is no so effective in managing the symptoms of COVID-19.
Myths: Antibacterial drugs do not work on COVID-19 as COVID-19 is caused due to the virus SARS-CoV-2 and not a bacteria. Viruses change the molecular programming of the body while bacteria work by attacking the cells by various means.
Plasms Transfusion: Convalescent Plasma: Convalescent refers to anyone recovering from a disease. Plasma is the yellow, liquid part of blood that contains antibodies. Antibodies are proteins made by the body in response to infections. Convalescent plasma from patients who have already recovered from coronavirus disease 2019 (COVID-19) may contain antibodies against COVID-19. Giving this convalescent plasma to hospitalized people currently fighting COVID-19 may help them recover.
There are at least 50 vaccine trials going on worldwide for COVID-19.
|Ad5-nCoV||Recombinant vaccine (adenovirus type 5 vector)||CanSino Biologics||Phase 3||Tongji Hospital; Wuhan, China|
|AZD1222||Replication-deficient viral vector vaccine (adenovirus from chimpanzees)||The University of Oxford; AstraZeneca; IQVIA; Serum Institute of India||Phase 3||The University of Oxford, the Jenner Institute|
|CoronaVac||Inactivated vaccine (formalin with alum adjuvant)||Sinovac||Phase 3||Sinovac Research and Development Co., Ltd.|
|JNJ-78436735 (formerly Ad26.COV2-S)||Non-replicating viral vector||Johnson & Johnson||Phase 3||Johnson & Johnson|
|mRNA-1273||mRNA-based vaccine||Moderna||Phase 3||Kaiser Permanente Washington Health Research Institute|
|No name announced||Inactivated vaccine||Wuhan Institute of Biological Products; China National Pharmaceutical Group (Sinopharm)||Phase 3||Henan Provincial Center for Disease Control and Prevention|
|NVX-CoV2373||Nanoparticle vaccine||Novavax||Phase 3||Novavax|
|Bacillus Calmette-Guerin (BCG) vaccine||Live-attenuated vaccine||University of Melbourne and Murdoch Children’s Research Institute; Radboud University Medical Center; Faustman Lab at Massachusetts General Hospital||Phase 2/3||University of Melbourne and Murdoch Children’s Research Institute; Radboud University Medical Center; Faustman Lab at Massachusetts General Hospital|
|BNT162||mRNA-based vaccine||Pfizer, BioNTech||Phase 2/3||Multiple study sites in Europe and North America|
|Covaxin||Inactivated vaccine||Bharat Biotech; National Institute of Virology||Phase 2|
|No name announced||Recombinant vaccine||Anhui Zhifei Longcom Biopharmaceutical, Institute of Microbiology of the Chinese Academy of Sciences||Phase 2|
|ZyCoV-D||DNA vaccine (plasmid)||Zydus Cadila||Phase 2||Zydus Cadila|
|AG0301-COVID19||DNA vaccine||AnGes, Inc.||Phase 1/2||AnGes, Inc.; Japan Agency for Medical Research and Development|
|BBIBP-CorV||Inactivated vaccine||Beijing Institute of Biological Products; China National Pharmaceutical Group (Sinopharm)||Phase 1/2||Henan Provincial Center for Disease Control and Prevention|
|GX-19||DNA vaccine||Genexine||Phase 1/2|
|INO-4800||DNA vaccine (plasmid)||Inovio Pharmaceuticals||Phase 1/2||Center for Pharmaceutical Research, Kansas City. Mo.; University of Pennsylvania, Philadelphia|
|LUNAR-COV19 (ARCT-021)||Self-replicating RNA vaccine||Arcturus Therapeutics and Duke-NUS Medical School||Phase 1/2||Duke-NUS Medical School, Singapore|
|No name announced||Self-amplifying RNA vaccine||Imperial College London||Phase 1/2||Imperial College London|
|No name announced||Protein subunit vaccine||Sanofi; GlaxoSmithKline||Phase 1/2||Various|
|Sputnik V||Non-replicating viral vector||Gamaleya Research Institute, Acellena Contract Drug Research and Development||Phase 1/2||Various|
|EpiVacCorona||Peptide vaccine||Federal Budgetary Research Institution State Research Center of Virology and Biotechnology||Phase 1/2||Federal Budgetary Research Institution State Research Center of Virology and Biotechnology|
|AdimrSC-2f||Protein subunit vaccine||Adimmune||Phase 1||Adimmune|
|COVAX-19||Monovalent recombinant protein vaccine||Vaxine Pty Ltd.||Phase 1||Royal Adelaide Hospital|
|CVnCoV||mRNA-based vaccine||CureVac||Phase 1||CureVac|
|GRAd-COV2||Adenovirus-based vaccine||ReiThera; Leukocare; Univercells||Phase 1||Lazzaro Spallanzani National Institute for Infectious Diseases|
|No name announced||Plant-based adjutant vaccine||Medicago; GSK; Dynavax||Phase 1||Medicago|
|No name announced||Protein subunit vaccine||CSL; The University of Queensland||Phase 1|
|SCB-2019||Protein subunit vaccine||GlaxoSmithKline, Sanofi, Clover Biopharmaceuticals, Dynavax and Xiamen Innovax||Phase 1||Linear Clinical Research (Australia)|
|V590||Recombinant vaccine (vesicular stomatitis virus)||Merck; IAVI||Phase 1|
|V591||Measles vector vaccine||University of Pittsburgh’s Center for Vaccine Research||Phase 1||University of Pittsburgh; Themis Biosciences; Institut Pasteur|
|UB-612||Multitope peptide-based vaccine||COVAXX||Phase 1||United Biomedical Inc. (UBI)|
|AAVCOVID||Gene-based vaccine||Massachusetts Eye and Ear; Massachusetts General Hospital; University of Pennsylvania||Pre-clinical|
|AdCOVID||Intranasal vaccine||Altimmune||Pre-clinical||University of Alabama at Birmingham|
|bacTRL-Spike||Monovalent oral vaccine (bifidobacteria)||Symvivo||Pre-clinical||Symvivo Corporation|
|ChAd-SARS-CoV-2-S||Adenovirus-based vaccine||Washington University School of Medicine in St. Louis||Pre-clinical||Washington University School of Medicine in St. Louis|
|HaloVax||Self-assembling vaccine||Voltron Therapeutics, Inc.; Hoth Therapeutics, Inc.||Pre-clinical||MGH Vaccine and Immunotherapy Center|
|HDT-301||RNA vaccine||University of Washington; National Institutes of Health Rocky Mountain Laboratories; HDT Bio Corp||Pre-clinical|
|LineaDNA||DNA vaccine||Takis Biotech||Pre-clinical||Takis Biotech|
|No name announced||Ii-Key peptide COVID-19 vaccine||Generex Biotechnology||Pre-clinical||Generex|
|No name announced||Recombinant vaccine||Vaxart||Pre-clinical||Vaxart|
|No name announced||Protein subunit vaccine||University of Saskatchewan Vaccine and Infectious Disease Organization-International Vaccine Centre||Pre-clinical||University of Saskatchewan Vaccine and Infectious Disease Organization-International Vaccine Centre|
|No name announced||Adenovirus-based vaccine||ImmunityBio; NantKwest||Pre-clinical|
|No name announced||Recombinant vaccine||Sanofi, Translate Bio||Pre-clinical|
|No name announced||mRNA-based vaccine||Chulalongkorn University’s Center of Excellence in Vaccine Research and Development||Pre-clinical|
|No name announced||gp96-based vaccine||Heat Biologics||Pre-clinical||University of Miami Miller School of Medicine|
|PittCoVacc||Recombinant protein subunit vaccine (delivered through microneedle array)||UPMC/University of Pittsburgh School of Medicine||Pre-clinical||University of Pittsburgh|
|No name announced||Inactivated vaccine||Shenzhen Kangtai Biological Products||Pre-clinical|
|No name announced||mRNA lipid nanoparticle (mRNA-LNP) vaccine||CanSino Biologics, Precision NanoSystems||Early research|
Preclinical Stage: How will this vaccine work?
This research-intensive stage is designed to find natural or synthetic antigens—foreign substances that induce an immune reaction in your body—that trigger the same reaction an actual virus or bacteria would. Identifying the right antigen or antigens can often take up to four years.
Phases 1/2a and 2b: Is it safe, and what’s the right dose?
Phase 1 testing marks the first time the vaccine is tested in a small group of adults, usually between 20 to 80 people, to evaluate its safety and measure the immune response it generates. Phase 2a studies aim to determine the most effective dose and expand the safety experience with the vaccine. Phase 1 and 2a clinical trials normally last several months to even a year before proceeding to Phase 2b or Phase 3 trials, in which the pool of people receiving the vaccine increases.
Phase 3: How effective is the vaccine?
In this stage of the clinical trial, even more volunteers receive the vaccine to study whether it’s effective. Before volunteers are vaccinated, they will be tested to make sure they currently do not have the SARS-CoV-2 virus. Half of the group will be assigned to receive the vaccine; the other half will receive a placebo. Then they will all be followed closely for up to two years to see if they do develop COVID-19-related symptoms, such as fever, headache, shortness of breath, dry cough or gastrointestinal distress.
Phase 4: Regulatory approval and licensure: Is it ready for the world?
After a successful Phase 3 trial, vaccine manufacturers apply to regulatory bodies such as the European Commission or the U.S. Food and Drug Administration (FDA). At this stage, clinical trial data is reviewed to make sure the vaccine is safe and effective. the manufacturing process is also reviewed.
Phase 5: Will it stay safe down the road?
Even after the vaccine is approved and licensed, regulatory agencies stay involved, continuing to monitor production; inspecting manufacturing facilities; and testing vaccines for potency, safety and purity.
Note: Typically, a vaccine development cycle takes 10 -14 years. In the case of COVID-19 the goal is to identify a potential mass-produced vaccination in next 2 years and get people vaccinated for less cost or free.
- World economy/ global GDP may shrink by a baseline of 5.2 % in 2020 due to COVID-19
- Global airlines have taken a big hit on revenue due to reduced number of flight and travel restrictions. Daily flights have shrunk by 48 %.
- Crude Oil: Crude oil is stabilized at 5-year low levels.
- Poverty projections suggest that the social and economic impacts of the crisis are likely to be
quite significant. Estimates based on growth projections from the June 2020 Global Economic
Prospects report show that, when compared with pre-crisis forecasts, COVID-19 could push 71
million people into extreme poverty in 2020 under the baseline scenario and 100 million under the
downside scenario. As a result, the global extreme poverty rate would increase from 8.23% in 2019
to 8.82% under the baseline scenario or 9.18% under the downside scenario, representing the first
increase in global extreme poverty since 1998, effectively wiping out progress made since 2017.
While a small decline in poverty is expected in 2021 under the baseline scenario, projected impacts
are likely to be long-lasting.
- Under the baseline scenario, COVID-19 could generate 176 million additional poor at $3.20 and 177 million additional poor at $5.50. This is equivalent to an increase in the poverty rate of 2.3 percentage points compared to a no-COVID-19 scenario. Almost half of the projected new poor will be in South Asia, and more than a third in Sub-Saharan Africa. Under the baseline scenario, the number of extreme poor in IDA, Blend and FCV countries is projected to increase by 21, 10 and 18 million, respectively