Souhrid Sarkar, Amity University Kolkata
What is COVID-19?
Coronaviruses are a family of viruses that may cause mild to severe respiratory disorders including death. The term ‘Corona’ means crown-like spikes on the surface of the virus. Some of the examples of coronavirus are Severe acute respiratory syndrome (SARS), the Middle East respiratory syndrome (MERS), and the common cold. The new strain of coronavirus was first reported in Wuhan, China in December 2019. The virus from then on has spread to all continents, except Antarctica.
Vaccine & Its Development
The vaccine is a preparation of genetic material, such as a strand of synthesized mRNA that is used by the cells of the body to produce an antigenic substance, such as a fragment of the virus spike protein.
To develop safe and effective vaccines usually five to ten years on average are required. Though nowadays, we have various resources and funding, and hence the process of developing a vaccine gets sped up. The development of a potential novel coronavirus vaccine is being partly led by experts who were already developing vaccines for other coronaviruses as it was identified as the biggest possible pandemic in the coming years after the outbreak of SARS and MERS.
The Process of Vaccine Development
Vaccine Candidates: It involves isolating the live virus before inactivating or weakening it and then determining whether it is a modified virus or not, this helps in producing immunity in people.
Pre-clinical testing: Testing is usually carried out in animals to give an idea of responses in humans. These are also used to check the effectiveness of the vaccine.
Clinical Trials: This step is when many promising potential vaccines fail. Mainly there are three phases of a clinical trial :
- Testing on a few dozen healthy volunteers (for checking the safety of administering the vaccine)
- Testing on several hundred people for efficacy – usually, it is given to the population who are at the risk of the disease to check the efficacy of the vaccine.
- Testing on thousands of people for efficacy and safety of the vaccine
Regulatory Approval & Production :
If similar kind of vaccine was approved in the past, then the approval process is accelerated and thus the vaccine is approved for production. And once a vaccine has been produced at a small scale and passed safety tests, it can be used in clinical trials. Though it is to be noted that, full licensure of vaccine can be considered in a public health emergency.
COVID Vaccines Available in India
Till now India has approved two vaccines – Covaxin and Covishield for emergency use in the country. So, now let us have a look at the difference.
COVAXIN :
Other Names : BBV152
Manufacturer : It was developed by Hyderabad-based Bharat Biotech.
Type : It is based on an inactivated whole SARS-CoV-2 virion, which in past was used to make polio vaccines.
Dose Interval : Two doses and the second dose should be administered four to six weeks after the 1st dosage.
Delivery Route : Through intramuscular injections.
Efficacy : 78 per cent in the second interim analysis and 100 per cent efficacy against ‘severe Covid-19 disease’.
Age group of beneficiaries : 12 years and above
Storage : 2 to 8 °C
COVISHIELD :
Other Names : AZD1222, ChAdOx1 nCoV-19, ChAdOx1-S, COVID-19 Vaccine AstraZeneca
Manufacturer: The Oxford-AstraZeneca vaccine is being locally manufactured by the Serum Institute of India (SII).
Type: It is based on the viral vector platform. A chimpanzee adenovirus known as ChAdOx1 is the vector that has been modified to carry the coronavirus spike protein into human cells.
Dose Interval: Two doses and the second dose should be administered six to eight weeks after the 1st shot.
Delivery Route: Through intramuscular injections.
Efficacy: 70 percent, but it can be over 90 percent when administered as a half dose followed by a full dose a month later.
The age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C
Other Authorised COVID Vaccines Across The World
The worldwide aim to create a safe and effective COVID-19 vaccine is being fruitful. More than a dozen vaccines now have been authorized around the globe, some of them are :
MODERNA :
Other Names: mRNA-1273, CX-024414, COVID-19 mRNA Vaccine Moderna.
Manufacturer: It is developed by Moderna in the United States National Institute of Allergy and Infectious Diseases and the Biomedical Advanced Research and Development Authority.
Type: It is based on nucleoside-modified mRNA encoding a spike protein of SARS-CoV-2, that is encapsulated in lipid nanoparticles.
Dose Interval: Two doses and the second dose should be administered 28 to 42 days after the 1st dosage.
Delivery Route: Through intramuscular injections.
Efficacy: 94.1 percent from the clinical analysis and 100 percent efficacy against ‘severe Covid-19 disease’.
The age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C
NOVAVAX COVID-19 VACCINE :
Other Names: NVX-CoV2373
Manufacturer: Novavax and Coalition for Epidemic Preparedness Innovations, US
Type: It is a recombinant nanoparticle vaccine consisting of both protein subunit and a virus-like particle.
Dose Interval: Two dosage vaccine and 2nd shot is taken 21 days apart.
Delivery Route: Through intramuscular injections.
Efficacy: 89% efficacy rate from interim analysis with 100% efficacy against severe disease.
The age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C
Pfizer–BioNTech COVID-19 VACCINE (INN: tozinameran ) :
Other Names: BNT162b2
Manufacturer: It is developed by Pfizer, Inc., and BioNTech
Type: It is based on nucleoside-modified mRNA encoding a mutated form of the full-length spike protein of SARS-CoV-2, that is encapsulated in lipid nanoparticles.
Dose Interval: Two doses and the second dose should be administered 21 days after the 1st shot.
Delivery Route: Through intramuscular injections.
Efficacy: 52% effective after the first dose, and about 95% effective after the second shot.
The age group of beneficiaries: 16 years and above
Storage: −80 and −60 °C, till 5 days before vaccination and then it has to be stored at 2 to 8 °C
SPUTNIK V COVID-19 VACCINE :
Other Names: Gam-COVID-Vac
Manufacturer: Gamaleya Research Institute of Epidemiology and Microbiology, Russia
Type: It is a vector vaccine that is based on adenovirus DNA, in which the SARS-CoV-2 coronavirus gene is integrated.
Dose Interval: Two slightly different versions of the vaccine for the first and the second dose given 21 days apart. Both the shots target the coronavirus’s distinctive “spike”, but they use different vectors – the neutralized virus that carries the spike to the body.
Delivery Route: Through intramuscular injections.
Efficacy: 91.6% efficacy rate from interim analysis with high response in curbing down severe complications of the disease.
The age group of beneficiaries: 18 years and above
Storage: A ready-to-use solution in water stored at −18 °C or 0 °F or below & a freeze-dried powder named as “Gam-COVID-Vac-Lyo” stored at 2–8 °C
SPUTNIK LIGHT VACCINE is a single shot vaccine with an efficacy of 79% has been also released to fight acute outbreaks allowing several people to get vaccinated fast. It contains the 1st dose of the Sputnik V vaccine, i.e., the Ad26 vector.
EpiVacCorona :
Manufacturer: VECTOR Center of Virology, Russia
Type: It is a peptide-based vaccine that provokes an immune reaction against COVID-19
Dose Interval: Two doses and the second dose should be administered 21 days or 3 weeks after the 1st shot.
Delivery Route: Through intramuscular injections.
Efficacy: 92% effective after the first dose, and 100% effective in preventing severe complications of the disease.
The age group of beneficiaries: Recommended for 18 years and above
Storage: 2 to 8 °C
SINOPHARM COVID-19 VACCINE :
Other Names: Sinopharm BBIBP-CorV
Manufacturer: Sinopharm and the Beijing Institute of Biological Products Co.
Type: It is an inactivated virus vaccine which has been used for many decades, such as vaccines against rabies, polio and hepatitis A.
Dose Interval: Two dose schedules and the second dose should be administered 3 to 4 weeks after the 1st shot.
Delivery Route: Through intramuscular injections.
Efficacy: 86% efficacy rate from interim trials with 100 percent efficacy against ‘moderate to severe Covid-19 disease’.
The age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C and also it can be stored at normal refrigeration temperatures
SINOVAC COVID-19 VACCINE :
Other Names : CoronaVac
Manufacturer: Sinovac Biotech., China
Type: It is an inactivated pathogen that is made by growing the whole virus in a lab and then killing it and is similar to the polio vaccine.
Dose Interval: Two dosage vaccines and the second dose should be administered 2 to 3 weeks after the 1st shot.
Delivery Route: Through intramuscular injections.
Efficacy: CoronaVac’s efficacy at just above 50% with 80-85 percent efficacy against disease complication.
Age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C
CONVIDICEA VACCINE :
Other Names : AD5-nCOV
Manufacturer : CanSino Biologics,China
Type: It is based on replication-defective adenovirus type 5
Dose Interval: Single-dose vaccine.
Delivery Route: Through intramuscular injections and nasal administration
Efficacy: 65.28% efficacy rate from interim analysis with 90.07 to 95.47% efficacy against severe disease.
The age group of beneficiaries: 18 years and above
Storage: 2 to 8 °C
JOHNSON & JOHNSON COVID-19 VACCINE :
Other Names : Janssen COVID-19 Vaccine , Ad26.COV2.S , JNJ-78436735 , Ad26COVS1 , VAC31518
Manufacturer: Janssen Vaccines, Netherlands, and its Belgian parent company Janssen Pharmaceuticals and subsidiary of American company Johnson & Johnson.
Type: It is a viral vector vaccine that is based on a human adenovirus which has been modified to carry the gene for making the spike protein of the SARS-CoV-2 virus.
Dose Interval: A single dose vaccine.
Delivery Route: Through intramuscular injections.
Efficacy: 66% efficacy rate from clinical trials with 100% efficacy against severe complications caused by the disease.
The age group of beneficiaries: Not reported
Storage: 2 to 8 °C
CONCLUSION
As of March 2021, 308 vaccine candidates are in various stages of development, with 73 in clinical research, including 24 in Phase I trials, 33 in Phase I–II trials, whereas16 in Phase III development.
Some of the examples of such vaccine are :
ZyCoV-D ( DNA vaccine which is in phase 3 trial and is manufactured by Zydus Cadila, India)
Valneva or VLA2001(Inactivated SARS-CoV-2 vaccine which is in phase 3 trial and is manufactured by French biotechnology company Valneva SE, France)
Sanofi–GSK COVID-19 vaccine or VAT00002 (Adjuveneted recombinant protein-based vaccine which is in phase 3 trial and is manufactured by Sanofi Pasteur and GSK, France & UK)
BBV154 (Adenovirus vector intranasal vaccine which is in phase 1 trial and is manufactured by Bharat Biotech, India)
INO-4800 (DNA plasmid vaccine which is in phase 2 trial and is manufactured by Inovio Pharmaceuticals, South Korea in collaboration with USA and China)
CureVac COVID-19 vaccine or CVnCoV (Unmodified RNA vaccine which is in phase 3 clinical trial and is manufactured by CureVac N.V. and the Coalition for Epidemic Preparedness Innovations (CEPI), Germany)
While vaccines gradually reduce the possibility of infection so it is possible for fully vaccinated people to contract and spread COVID-19. Hence even if you are vaccinated, you are recommended to wear face masks, maintain social distance, and regularly wash hands. So together we can fight Covid-19 and make the world safe and healthier.
“Hope begins in the dark. The stubborn hope that if you just show up and try to do the right thing, the dawn will come. You wait and watch and work: you don’t give up.” – Anne Lamott
Also read: PurZ : A new virus genome on the block!!!
REFERENCES :
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2. “Coronavirus vaccine development: from SARS and MERS to COVID-19”. Journal of Biomedical Science. 27 (1): 104. doi:10.1186/s12929-020-00695-2. PMC 7749790. PMID 33341119
3. “Moderna develops new vaccine to tackle mutant Covid strain”. Financial Times.
4. “Johnson & Johnson Announces Single-Shot Janssen COVID-19 Vaccine Candidate Met Primary Endpoints in Interim Analysis of its Phase 3 ENSEMBLE Trial” Johnson & Johnson
5. “Covid-19: Oxford-AstraZeneca vaccine approved for use in UK”. BBC
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7. “Sanofi and Translate Bio initiate Phase 1/2 clinical trial of mRNA COVID-19 vaccine candidate” (Press release). Sanofi.
8. “Safety, Tolerability, and Immunogenicity of the COVID-19 Vaccine Candidate (VBI-2902a)”, United States National Library of Medicine.
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