COVID 19 Vaccines UPSC
There are two categories of COVID-19 Vaccines: Component Viral Vaccines and Whole Virus Vaccines.
Component Viral Vaccines
- Protein Subunit: Contains isolated and purified viral proteins e.g. Epivaccorona, Novavax.
- Virus-like Particles (VLP): Contains viral proteins that mimic the structure of the virus, but no genetic material
- DNA-based and RNA-based: Contains viral genetic material (such as mRNA) which provides the instructions for making viral proteins e.g. Pfizer, Moderna
- Non-Replicated Viral Vector: Contains viral genetic material packaged inside another harmless virus that cannot copy itself. e.g. Sputnik V, Astrazeneca and Oxford (COVISHIELD), Johnson and Johnson.
- Replicating Viral Vector: Contains viral genetic material packaged inside another harmless virus that can copy itself
Whole Virus Vaccines
- Inactivated: Contains copies of the virus that have been killed (inactivated) e.g. Sinopharm, Sinovac, Covaxin
- Live-Attenuated: Contains copies of the virus that have been weakened (attenuated)
COVID VACCINES IN INDIA
Two vaccines were granted emergency use authorization by the Central Drugs Standard Control Organization (CDSCO) in India, Covishield® (AstraZeneca’s vaccine manufactured by Serum Institute of India) and Covaxin® (manufactured by Bharat Biotech Limited).
COVISHIELD
- Covishield® vaccine, manufactured by the Serum Institute of India, is a Viral Vector-based Technology which is also used to manufacture Ebola vaccine.
- Composition of Covishield includes inactivated adenovirus with segments of Coronavirus, Aluminium Hydroxide Gel, L-Histidine, L-Histidine Hydrochloride Monohydrate, Magnesium Chloride Hexahydrate, Polysorbate 80, Ethanol, Sucrose, Sodium Chloride, and Disodium Edetate Dihydrate (EDTA).
- The time interval between two doses of the Covishield vaccine has been extended from four-eight weeks to 12-16 weeks.
COVAXIN
- Covaxin® vaccine, manufactured by the Bharat Biotech, is a Whole-virion Inactivated Coronavirus Vaccine which is also used to manufacture vaccines like Influenza, Rabies and Hepatitis- A.
- Composition of Covaxin includes inactivated Coronavirus, Aluminum Hydroxide Gel, TLR 7/8 Agonist, 2-Phenoxyethanol and Phosphate Buffered Saline [NKA1].
- The second dose of Covaxin can be taken four to six weeks after the first.
As the vaccines available are not interchangeable, it is important to receive the second dose of same vaccine as the first one. The Co-WIN portal is also going to help to ensure that everyone receives the same vaccine.
Both vaccines need to be stored and transported at +20 to +8⁰ Celsius.
Contraindications
Persons with history of:
- Anaphylactic or allergic reaction to a previous dose of COVID-19 vaccine
- Immediate or delayed-onset anaphylaxis or allergic reaction to vaccines or injectable therapies, pharmaceutical products, food-items etc.
Pregnancy & Lactation:
- Pregnant & Lactating women have not been part of any COVID-19 vaccine clinical trial so far. Therefore, women who are pregnant or not sure of their pregnancy; and lactating women should not receive COVID-19 vaccine at this time
Provisional / temporary contraindications:
In these conditions, COVID-19 vaccination is to be deferred for 4-8 weeks after recovery
- Persons having active symptoms of SARS-CoV-2 infection.
- SARS-COV-2 patients who have been given anti-SARS-CoV-2 monoclonal antibodies or convalescent plasma
- Acutely unwell and hospitalized (with or without intensive care) patients due to any illness.
APRIL 2021
Sputnik – V has been granted EUA in the month of April 2021.
Sputnik V is an adenovirus viral vector vaccine for COVID-19 developed by the Gamaleya Research Institute of Epidemiology and Microbiology in Russia. It is the world’s first registered combination vector vaccine for the prevention of COVID-19.
Given IM (Day 01 and Day 21). Sputnik lite-Only single dose.
AUGUST 2021
ZyCov-D
August, the government of India granted Emergency Use Authorization to a COVID-19 DNA vaccine. Pharmaceutical firm Zydus Cadila, in partnership with India’s Department of Biotechnology, developed the 3-dose intradermal vaccine, called ZyCov-D, which is authorized there for use in people aged 12 years or older. The endorsement marks the first clinical use of a DNA vaccine in humans.
APRIL 2022
The national drugs controller has cleared children as young as 5 years old to be vaccinated with Biological E’s Corbevax.
Corbevax is a “recombinant protein sub-unit” vaccine. It is administered through an intramuscular route with two doses scheduled 28 days apart and is stored at 2 to 8 degrees.
SEPTEMBER 2022
India gets its first Nasal Covid-19 vaccine
- iNCOVACC
- ChAd36-SARS-CoV-S COVID-19 (Chimpanzee Adenovirus Vectored) Recombinant vaccine
- Storage temperature 2-6 degree celsius
- Developed by Bharat Biotech
- Approved for primary immunization in those 18 years and above (CDSCO restricted use in emergencies/Drugs Controller General of India (DCGI))
- It’s only the second such vaccine in the world, after CanSino Biologics’ vaccine in China, to get regulatory approval.
- Induce local/Mucosal immunity
Key attributes of iNCOVACC
- Stimulates a broad immune response, neutralising antibody (IgG, mucosalIgA) and T cell responses
- Immune responses at the site of infection (nasal mucosa) essential for blocking both infection and transmission of Covid-19
- Non-invasive, needle-free
Ease of administration:
- Does not require trained health care workers
- Scalable manufacturing
