When did Covid19 begin?
Covid19 outbreak was initially reported from Wuhan, China on 31st of December,2019. This outbreak has reached out of the hands of humans because of its rapid spread.
The World health organization (WHO) announced Covid19 as a global health emergency on the 30th of January 2020. As predicted, this became a global pandemic by March 2020 according to WHO.
The Covid19 pandemic broke into many countries and territories proving that it can be a major turning point in human existence on the planet. With the rapid spread, it has taken millions of lives away within a very short period.
By June 2021, there are 220 countries across the world dealing with the Covid19 pandemic. With so many behavioral restrictions, some countries have taken the virus into control. But with the rapid genetical modifications, the virus still keeps adapting and spreading in several ways.
What causes Covid19?
As you see the name, Covid19 is the abbreviation of “Corona Virus Disease 2019”. This novel virus belongs to the family of “Severe Acute Respiratory Syndrome” (SARS) viruses. And therefore it can also be addressed as “SARS-COV-2”.
Looking further into its structure, the Covid19 virus has been identified as a Beta coronavirus by its phylogenetic relationships. This virus comprises a single strand positive sense RNA as its nucleic acid component.
This RNA strand is housed by a matrix protein capsid. The matrix proteins include Spike glycoprotein, envelop small membrane proteins, membrane proteins, nucleoproteins, and Hemagglutinin esterase enzyme.
How Covid19 infects the human body
In the infection process of the Covid19 virus, there are 3 stages.
- 1st stage is the asymptomatic period. This can be 2-4 days according to the immunity of the person. When a person inhales the SARS-COV-2 virus, it goes with the airflow and binds with the nasal cavity ciliated columnar epithelial cells.
The receptor which is responsible for this is, ACE2. After binding with the epithelial cells, it starts replicating with the usage of RNA polymerase enzyme available in the epithelial cell.
- 2nd stage is the propagation of the virus into lower areas of the respiratory tract. This period can be a few days. In this period the disease can be clinically manifested. The innate immunity responses of the person trigger in this period.
For the clinical manifestations, the level of CXCL10 which is an innate response cytokine rises. In this stage, the worsening or the curing of the disease depends on the immunity of the host.
- 3rd stage is the most aggressive stage of the virus if it is kept untreated. The virus infiltration to the lungs and type 2 alveolar cells occur in this period. With rapid replication, most of the type 2 cells can be damaged. And as the type 2 cells act as the precursor of type 1 alveolar cells, the regeneration of cells can be delayed too.
With the alveolar damages caused by the SARS-COV-2 pathogen, accumulation of fibrin-rich hyaline and giant multinuclear cells occurs in the alveolar cells. This leads to more fibrosis and scarring in the alveolar cells.
Unless the patient possessing vigorous cellular regeneration and good innate immunity this condition cannot be reversed easily. In the end, the gas exchange becomes low and the patient will suffer from hypoxia conditions.
The 3rd stage can be only treated with the fixation of Oxygen ventilators and specific antiviral drugs. And the 2nd stage and 1st stage can be cured with regular steaming and consuming immune-boosting food and drinks.
With the uncontrollable spread of the Covid19 pandemic, so many countries kept a foot forward to develop vaccines. The vaccination synthesis procedure usually takes about 5 years to release a proper vaccine to the local market. But in this emergency, most of the pharmaceutical companies tried to experiment with different vaccines in an express mode.
Of every 100 vaccines, approximately 7 were eligible for human trials. In this case, you will doubt what the best vaccine is. But the vaccines released up to date were assured for their safety and efficacy by the WHO.
WHO recommends you to get any of the vaccines without waiting for the best. Vaccination prepares your body to fight productively with the virus by enhancing the innate immunity of the body.
This is done by letting the body prepare immunoglobulins or antibodies. If these antibodies are specified to fight against the SARS family of viruses, they will fight against SARS-COV-2 (COVID19) virus too.
Sometimes you can catch the COVID19 infection even though you have got the vaccine. But the severity of the disease can be reduced with prior vaccination. And the mortality rate can be reduced by a proper vaccination program in a country. Out of the vaccine brands, some are widely used in many countries.
COVID19 vaccine types
Vaccines usually provide an artificial active immunization or an artificial passive immunization. The COVID19 vaccines are mainly artificial active immunizations until today. The antibodies extracted against the specific SARS-COV-2 virus will give the artificial passive immunization. But that method is not currently practiced and hopefully, it will be developed in the future.
When producing artificial active immunization there are 4 main types.
- Whole virus- when giving the whole vaccine, the live attenuated viruses, inactive viruses are administered. These viruses cannot replicate inside the body. But as it is a foreign pathogen body will prepare antibodies to fight against it. And these antibodies can last long to fight a live active virus of the same virus family.
- Protein subunits of the virus- protein subunits of a virus can also trigger the synthesis of antibodies inside our body. But this immunization can be weaker than injecting the whole virus. In the case of Covid19, the virus spike proteins are given this way.
- Viral vector- in this case, a weaker live virus is injected. They can be replicating or non replicating. Usually, some adenoviruses are given in this manner. This method triggers an effective synthesis of antibodies. In some COVID19 vaccines, this method is preferred.
- virus nucleic acids (RNA or DNA) – in these vaccines the genetic substances of the virus will be given. But these vaccines consume extreme conditions such as -70C to keep in the good condition. This RNA and DNA are recognized by our body as foreign pathogens and it helps to boost up immunity.
In addition to these 4 types virus-like particles, antigen-presenting cells, cell-based vaccines, and many other inclusions are also produced.
Available vaccines for COVID19
Although many countries started experimenting on different vaccines, a few vaccines were only assured for minimal side effects. This review process is done by the Strategy Advisory Group of Experts on Immunization (SAGE) of WHO. This is the list of Covid19 vaccines approved by WHO so far.
- Pfizer-BioNTech Covid19 vaccine
- Moderna Covid19 vaccine
- Johnson & Johnson’s Janssen Covid19 vaccine
- Oxford AstraZeneca Covid19 vaccine
- Novavax Covid19 vaccine
- Sputnik V Covid19 vaccine’
- Sinovac Covid19 vaccine
- Sinopharm Covid19 vaccine
- Covishield, Serum Institute of India Pvt. Ltd. Covid19 vaccine
- Covax, Bharath Biotech covid19 vaccine
|Vaccine||Origin||Inclusions and type||Storage conditions||Dosage given||cautions||side effects|
|Pfizer-BioNTech Covid19 vaccine||Collaboration of BioNTech company of Germany with Pfizer company in USA||mRNA and lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6-1-diyl)bis(2-hexyldecanoate), 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3-phosphocholine, and cholesterol), Potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodiuphosphate dehydrate, and sucrose.||-80C to -60C temperature for 6 months. Or 2C to 8C for 5 days||2 doses 3 weeks apart||allergies, fever, bleeding disorders or blood-thinning disorders, on immunocompromising medications, pregnancy, breastfeeding, have received another type of COVID19 vaccination, have ever fainted with previous vaccinations||severe allergic reactions, non-severe allergic reactions (such as rash, itching, hives, swelling), injection site pain, tiredness, headache, muscle pain, chills, joint pain, fever, injection site swelling, injection site redness, nausea, swollen lymph nodes, diarrhea, vomiting, arm pain.|
|Moderna covid19 vaccine||Cambridge, Massachusettes, USA||mRNA modified nucleoside||-25C to -15C temperature for 6 months. Or 2C to 8C for 30 days||2 doses 28 days(month) apart||severe anaphylaxis for any ingredient in COVID19 vaccine such as polyethylene glycol, and severe anaphylaxis after getting the first dose of the vaccine, hives, swelling, respiratory distress||redness, pain, swelling in the arm you got vaccinated, tiredness, headache, muscle pains, chills, fever, nausea|
|Johnson and Johnson’s Janssen covid19 vaccine||Janssen- Cilag international NV, Belgium||Viral vector||2C to 8C temperature for 3 months||1 dose||severe allergic conditions, hives, swelling, wheezing||pain, redness, and swelling of the arm you got vaccinated, tiredness, headache, muscle pain, chills, fever, nausea|
|Oxford AstraZeneca covid19 vaccine||Oxford University, England collaborated with AstraZeneca multinational company in Sweden||Viral vector, genetic code of SARS-COV-2 spike protein, Sucrose, acidity regulators such as histidine, sodium, and potassium salts||2C to 8C temperature for 6 months||Intramuscular doses o 0.5ml with an interval of 8-12 weeks||chronic respiratory disorders, chronic heart diseases, chronic kidney diseases, chronic liver diseases, chronic neurological diseases, diabetes, immunosuppression medications, spleen dysfunction, morbid obesity, severe mental illness, adult cares, younger adults in long-stay care homes||Arm pain, chills, fever, joint pains, muscle pains, fatigue, headache|
|Novavax Covid-19 vaccine||USA||protein subunits of spike proteins synthesized using recombinant nanotechnology (therefore these vaccines are stored in 2-8C temperature)||2C to 8C temperature||an intramuscular vaccine of 0.5ml. 2 doses with an interval of 21 days||not indicated||no serious adverse effects have been reported. Headache, fatigue, myalgia|
|Sputnik V (Gmaleya) covid19 vaccine||Gamaleya research institute of epidemiology, Russia||Adenovirus viral vector that uses a serotype 26 human adenovirus carrying SARS-COV-2 protein S gene, and serotype 5 human adenovirus vector carrying a SARS-COV-2 protein S gene||-18.5C temperature in liquid form or 2C to 8C temperature in dry form||2 doses of 0.5ml with a gap of 21 days||pregnant and breastfeeding women, individuals with thrombocytopenia||headache, fatigue, injection site adverse effects, non-severe allergic reactions (such as rash, itching, hives, swelling), injection site pain, muscle pain, chills, joint pain, fever, injection site swelling, injection site redness, nausea, swollen lymph nodes, diarrhea, vomiting, arm pain.|
|Sinovac covid19 vaccine. (Vero cell inactivated) CoronaVac||Sinovac Biotech Ltd., China||aluminum hydroxide adjuvanted, inactivated whole virus vaccine||2C to 8C temperature||intramuscular 2 doses of 0.5ml within 2-4 weeks||individuals with anaphylaxis for any component of the vaccine are contraindicated. If anaphylaxis caused after the first dose, the second dose wouldn’t be given, children under 18 years, pregnant women, breastfeeding women, immunosuppressant persons, persons who have previously vaccinated for SARS-COV-2 infection, persons with current acute covid19 infection, persons who have already received passive antibody therapy for covid19||injection site pain, injection site reactions, fatigue, diarrhea, muscle pain (these side effects may last for 2 days)|
|Covaxin covid19 vaccine||Bharath Biotech, India||6 micrograms of the whole virion inactivated SARS-COV-2 antigen, other inactive ingredients such as aluminum hydroxide gel, TLR agonist (imidazoquinolinone), 2- phenoxyethanol, phosphate buffer saline.||2C to 8C temperature||2 doses given 4 weeks apart||Individuals on regular medications for any illnesses, allergies, fever, bleeding disorders and blood-thinning disorders, immunocompromised medications, pregnant and breastfeeding women, received any covid19 vaccine before.||Injection site pain, headache, fever, malaise, nausea, vomiting, rashes, allergic reactions.|
|Sinopharm covid19 vaccine||Sinopharm pharmaceutical company, China||mRNA||2C to 8C temperature||2 doses of 0.5ml intramuscular vaccines with an interval of 3-4 weeks||individuals with a history of anaphylaxis, anyone with a body temperature over 38.5C, individuals with HIV are considered as high risk, pregnant and lactating women||fever, pain at the injection site, headaches, fatigue, injection site reactions. The severe side effects can be serious nausea and a rare neurological disorder called “acute disseminated encephalomyelitis”, blood clotting, redness, swelling at the injection site.|
|Covishield Covid19 vaccine||Serum Institute of India Pvt. Ltd.||ChAdOx1 nCoV-19 corona virus vaccine (recombinant) 5 * 10 viral particles. Recombinant replication-deficient chimpanzee adenovirus vector encoding the SARS-COV-2 spike glycoprotein. Produced in genetically modified human embryonic kidney (HEK) 293 cells, L- Histidine, L- Histidine hydrochloride monohydrate, magnesium chloride hexahydrate, polysorbate 80, ethanol, sucrose, sodium chloride, disodium edetate dihydrate (EDTA), water for injections.||2C to 8C temperature||2 doses of 0.5ml with an interval of 4-12 weeks||Previous anaphylaxis conditions to any inclusion of the covishield vaccine, fever, bleeding disorders, and blood thinning disorders, individuals getting immunocompromised medications, pregnant, breastfeeding women, if you have received another Covid19 vaccine||Tenderness, pain, warmth, redness, itching, swelling or bruising of the injection site, feeling unwell, feeling fatigued, chills, headaches, nausea, muscle pain, getting a lump at the injection site, vomiting, feeling dizzy, decreased appetite, abdominal pain, enlarged lymph nodes, excessive sweating, itchy skin, rashes|