Structure of COVID-19 virus
Function of Viral particles
Types of vaccine
Different types of vaccines
Future vaccination in India
4. Functions of proteins on virus:
1. S- Protein: Help in entry into host
2. N- Protein: Bound to RNA
genome to make up nucleocapsid
3. M- Protein: Shape of viral
4. E- Protein: Interact with m-
protein to form viral envelope
(Fig. 2: Functions of different proteins) 4
Pre-clinical Phase I Phase II In Use
Phase III Phase IV
Used in wide
Fig. 4: Vaccine development (https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section6.html) 6
7. Approved Vaccines (Worldwide):
• First COVID 19 vaccine released: Sputnik V (11th August 2020)
• First COVID 19 vaccine to be authorized: (8th December 2020)
1. Pfizer-BioNTech (90year old female)
• First COVID 19 vaccine to be authorized in India: (16th January 2021)
1. Covishield (Sanitation worker in AIIMS)
8. Vaccines Type of
Developer Efficacy Storage
95% -70C 2 (21 days apart) Unknown
Moderna M-RNA Moderna, America 94.50% -20C 2 (28 days apart) Unknown
Sputnik V 2 Adenovirus
91.60% Fridge (dry) 2 (21 days Apart) Unknown
Janssen Adenovirus Johnson and
66% Fridge One dose Protect against
moderately to severe
BARDA, OWS 62% 2-8C 2 doses (12-16
UK variant and SA
Covaxin Inactivated Bharat biotech
81% 2-8C 2 (28 days apart) UK variant, Brazil
Variant, South African
variant, Double mutant
(Table 1: Vaccines available worldwide)
9. Indian Scenario:
• The largest vaccination drive.
• Digitalized platform: Co-WIN (COVID-19 Vaccine Intelligence Network)
• Vaccinators: Doctors, staff nurse, Pharmacist, ANM, Health visitors
• Vaccination priorities:
Health care workers > Population above 60 years > Population 45-60
years with comorbidities> Population 45-60years > Population 18-45 year
Source: https://www.mohfw.gov.in/pdf/LiberalisedPricingandAcceleratedNational Covid19VaccinationStrategy2042021.pdf
10. COVID -19 Vaccines in India:
• Currently 3 vaccines are
available in India.
• Anyone above > 18years of age.
• Free for all by central
(Fig. 5: Vaccines available in India) 10
11. Vaccines in India:
Vaccines Manufacturer Special points
COVAXIN Bharat Biotech,
ICMR a/w NIV
• Indigenous vaccine
• Inactivated cell derived technology (Does not replicate)
• Boosts T- helper cell response and cell mediated immunity
• 2 doses (28 days apart)
• No subzero storage
COVISHIELD Serum Institute
of India, Pune
• Spike protein(S) carried by replication deficient Chimpanzee adenovirus
• 2 separate doses of 0.5ml each, 12-16 week apart
• No subzero storage
• Effective against alpha, beta and delta variant
• Boosts T cell immunity
SPUTNIK-V Dr. Reddy
• 2 distinct adenovirus carriers in 2 doses, 21 days apart
• Works against all variants of COVID-19
• Storage: -18C (Liquid) and 2-8C (Lyophilized)
• Sputnik Light: single dose vaccine
(Table 2: Available vaccines in India) https://www.mohfw.gov.in/covid_vaccination/vaccination/faqs.html 11
13. Vaccination during pregnancy and
• None of the vaccine replicates inside human body producing Infection. So
Vaccination in these group of women is relatively safe.
• MoHFW, GOI started vaccinating these group women.
Lactating women: 19th may 2021.
Pregnant women: 25th June 2021.
• Caution: Every pregnant and lactating mother should be informed that, there
is no proven study for long term complication in foetus.
14. Delayed Vaccination:
• Vaccination should be delayed in special circumstances: (30-90 days)
1. Individual with confirmed or suspected COVID 19 infection.
2. Patient treated with convalescent plasma therapy.
3. Acute illness requiring hospitalization.
4. Individuals who have taken another vaccine in recent 14 days.
• Patient who are treated with convalescent plasma or monoclonal antibody showed no re infection
within 90 days. So, to prevent further antibody interference it is advised to be vaccinated after 90
15. Vaccine interchangeability:
• Vaccine interchangeability is not allowed.
• Special circumstances: m-RNA vaccines can be interchangeable.
• An Oxford university study: Pfizer and Astrazeneca vaccine
interchangeability at an interval of 4 weeks induced high antibody against
COVID-19 (Astrazeneca followed by Pfizer).
• Interval between COVID and non COVID vaccine: 14 days (Except
16. Side effects:
• Tenderness, pain, warmth,
redness, itching, swelling or
bruising at the site of injection
• Generally feeling unwell, fatigue,
• Chills, feverish
• Headache, nausea
• Joint pain and myalgia
Other less common Side effects
• Lump at the injection site
• Fever, vomiting
• Flu like symptoms (high fever,
sore throat, runny nose, mild
cough and chills)
• Increased thirst
Uncommon side effects
• Decreased appetite
• Abdominal pain
• Enlarged lymph node
• Itchy skin/ rash
• Sudden increase in body weight
(Table 3: Side-effects of vaccination)
17. Rare Complications:
• Delayed local injection site reaction : T cell mediated.
• Transient thrombo-inflammation ( in pro-inflammatory and pro-coagulative
• Venous thromboembolism
• Immune thrombocytopenic purpura
• Myocarditis and pericarditis
• Death (rarest)
18. CDC guideline:
For all current vaccines:
May receive COVID 19 vaccine (Includes: immunocompromised, autoimmune conditions)
May take vaccine
Adolescent >18 years people are eligible for all types of vaccines
16-17 years are eligible for Pfizer-BionTech vaccine
Contraindications Severe allergic reactions (e.g. anaphylaxis) to previous dose of vaccine
Immediate allergic reaction of any severity to a previous known component of vaccine
Precaution Immediate allergic reaction to any other vaccine or therapy
30 mins: People with precaution to vaccination
15 mins: For all others
(Table 4: CDC guideline) https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html
19. Future vaccines:
Nasal Vaccine by Bharat Biotech:
• m-RNA carried by chimpanzee adeno virus.
• Stimulates broad immune response (neutralizing IgG, mucosal IgA
and T cell response)
• Immune response at the site of infection (blocks both infection and
• Non-invasive route, needle free.
• High compliance (Suitable for children and adults)
(Fig. 6: Nasal vaccine)
20. Zydus DNA Vaccine (Needle free vaccine):
• Fully indigenous by company Zydus Cadila.
• Name: Zycov-D
• 3 dose schedule (0th, 28th, 56th day)
• Storage: 2-8C
First DNA vaccine in world
Vaccine codes virus spike protein using Plasmid DNA
Needle free administration : Ordinary hypodermic needle
• Might be a preferred vaccine for children
(Fig. 7: Needle free
21. Booster Dose:
• Pfizer and Moderna recently announced their booster dose after 6
• DCGI gave permission to Bharat Biotech to conduct 3rd shot Covaxin
clinical trial. (6months after second dose).
22. COVAT study (Corona Virus Vaccine-Induced
• Seropositivity rate increased to 95% in India after 2 doses of vaccine, including
both recovered and vaccinated individuals.
• After 2 doses of complete vaccination seropositive rates were 97.8% and 79.3%.
• Covaxin has significant increase in seropositivity and antibody titer after 2
• Covishield has 4 fold increase in median antibody titer even after second dose.
• There is no significant difference with respect to age, sex, BMI and blood group.