Vaccines

Vaccines


Vaccine Type/ ManufacturerMechanism of ActionDosingEfficacyAdverse Effects
COVISHIELD
AstraZeneca/
Oxford

Serum Institute of India
Viral Vector vaccine, chimpanzee adenovirusTwo doses; 4-12 weeks apart
  • 70% against symptomatic COVID-19.
  • 100% against severe COVID-19 and death.
  • Common: Arm soreness, fatigue, chills, fever, body aches, headache.
  • Rare: Deep vein thrombosis and pulmonary emboli
  • Very rare: Cerebral venous sinus thrombosis, splanchnic vein thrombosis and arterial thrombosis with thrombocytopenia
COVAXIN
Bharat Biotech,India
Inactivated, adjuvanted whole virion vaccineTwo doses;4 weeks apart
  • 81% against symptomatic COVID-19.
  • Common: Arm soreness, fatigue, chills, fever, body aches, headache.
Sputnik V/
Gam-COVID-Vac

Gamaleya Research Institute,Russia
Viral vector vaccine, recombinant human adenovirus 26 and 5Two doses; 3 weeks apart
  • 91% against symptomatic COVID-19
  • 100% against severe COVID-19
  • Common: Injection site reaction, Flu like illness
  • Rare: Venous thrombosis, Urolithiasis

COVISHIELD:

Also known as ChAdOx1 nCoV-19 or AZD 1222, this is an Adenovirus Vector Vaccine. A chimpanzee adenovirus is used as a carrier to deliver the DNA encoding for the spike protein of the corona virus to human cells. The adenovirus is replication deficient i.e. it enters the human cell but cannot replicate within the cell. The DNA is released in the cell, enters the nucleus of the cell and stimulates the production of messenger RNA (mRNA) that then instructs the cell to make spike protein fragments. These spike protein fragments are expressed on the surface of the cell and stimulate the immune system to recognize the spike protein. 

Clinical Trials:
Pooled results from Phase 3 trials in UK, Brazil and South Africa comprising 23, 848 participants demonstrated 62% efficacy against symptomatic COVID-19. However, a subset of trial participants given a lower initial dose demonstrated higher efficacy of 90% against symptomatic COVID-19. Increasing the interval between the two doses to 12 weeks is believed to increase efficacy. Vaccine was 100% efficacious at preventing hospitalization and death. 

 A phase 3 clinical trial in the US demonstrated 76% efficacy. Results were comparable across age groups, with vaccine efficacy of 85% (CI: 58% to 95%) in adults 65 years and older. Vaccine was 100% efficacious at preventing severe or critical disease and hospitalization. The vaccine was well tolerated, and no safety concerns related to the vaccine were identified during the trial.

The trial in South Africa was halted early as the vaccine did not show efficacy against mild/ moderate COVID-19 but is still believed to be efficacious against severe disease and death. Real world data from Scotland suggests 90% efficacy. This vaccine is currently being administered in 94 countries. 

Storage:
It can be stored and transported at 2-8˚C for 6 months and does not require special preparation prior to administering.

Dosing Interval:
2 doses, 4-12 weeks apart.

Adverse Effects:
Common adverse effects: Arm soreness, fatigue, chills, fever, body aches, headache.
Rare: Certain serious clotting complications have been reported after vaccination. These include deep vein thrombosis (DVT), pulmonary emboli (PE). The World Health Organization and the European Medical Agency concluded that the rate of DVT and PE was not higher than that expected.
Very rare: Blood clots in veins in the brain (cerebral venous sinus thrombosis, CVST) and the abdomen (splanchnic vein thrombosis) and in arteries, together with thrombocytopenia and sometimes bleeding. These occur primarily in women under the age of 60 years, within 4 weeks of the first dose of vaccine. Based on UK data, this is estimated to occur at a frequency of 4 cases/million doses of vaccine

COVAXIN:

This is an adjuvanted, inactivated/ killed whole Virion vaccine. When injected, the killed virus delivers the spike protein to antigen presenting cells. This helps activate T-helper cells which in-turn can induce B cells to produce antibodies. 

Clinical Trials:
Bharat Biotech announced the results of an Interim analysis of a phase 3, placebo controlled trial comprising 25,800 participants, 18 years or older. 36 cases of COVID-19 were observed in the placebo group versus 7 cases in the vaccine group, resulting in a point estimate of vaccine efficacy of 81%. There was no information provided on severity of cases, rates of hospitalization or death. They also reported a 70% reduction in asymptomatic SARS-CoV-2 infection suggesting reduction in transmission. A peer reviewed publication on the safety and efficacy of this vaccine is expected to be published in June. 

Storage:
It can be stored and transported at 2-8˚C

Dosing Interval:
2 doses, 4 weeks apart.

Adverse Effects:
Reported adverse effects include injection site reactions, headache, fever, nausea, myalgia, nausea and rash. More details pending peer reviewed publication of Phase 3 trial results.

Sputnik V/ Gam-COVID-Vac:

Introduction:
This is a heterologous recombinant adenovirus (rAd) based vaccine. The vaccine course consists of two doses, one of which contains rAd type 26 and the other rAd type 5, both of which carry the DNA encoding for SARS-CoV-2 spike protein. After injection, the adenovirus vector releases the DNA is released in the cell, This enters the nucleus of the cell and stimulates the production of messenger RNA (mRNA) that then instructs the cell to make spike protein fragments. These spike protein fragments are expressed on the surface of the cell and stimulate the immune system to recognize the spike protein.  

Clinical Trials:
A randomized, placebo controlled, phase 3 trial in Russia comprising 21, 977 reported 91% efficacy against symptomatic COVID-19 at day 21 after the first dose. 100% efficacy was reported against severe disease. This vaccine is now authorized in 12 countries. 

Storage:
It can be stored and transported at 2-8˚C for two months

Dosing Interval:
2 doses 21 days apart.

Adverse Effects:
Common adverse effects are mild and include injection site reactions, flu like symptoms, fatigue and headacheSingle cases of renal colic and deep venous thrombosis were reported in the vaccine group. It is not clear that this was related to vaccine administration.



Contra-indications to the vaccine are:

  • A known allergy to an ingredient in the vaccine (see ingredient list below)
  • A severe allergic reaction to a previous dose of vaccine is a contra-indication to the second dose of vaccine.

It should be safe for people with other types of allergies to receive the vaccine. An allergy to antibiotics such as penicillins or sulfas, allergies to foods, pollen etc. are NOT contra-indications to the vaccine.
List of ingredients in COVISHIELD:

  • Inactivated adenovirus with segments of Coronavirus
  • L-Histidine
  • L-Histidine hydrochloride monohydrate
  • Magnesium chloride hexahydrate
  • Polysorbate 80
  • Ethanol
  • Sucrose
  • Sodium chloride
  • Disodium edetate dihydrate

List of ingredients in COVAXIN:

  • Inactivated coronavirus
  • Aluminum Hydroxide gel
  • TLR 7/8 Agonist
  • 2-Phenoxyethanol
  • Phosphate Buffered Saline

List of ingredients in Sputnik V:
Component I:

  • Active substance: recombinant serotype 26 adenoviral particles, containing the SARS-CoV-2 protein S gene

Component II:

  • Active substance: recombinant serotype 5 adenoviral particles, containing the SARS-CoV-2 protein S gene
  • Additional ingredients in both components:
  • Tris- (hydroxymethyl)aminomethane
  • Sodium chloride
  • Sucrose
  • Magnesium chloride hexahydrate
  • EDTA-disodium salt dihydrate
  • Polysorbate 80
  • Ethanol

No. None of the COVID vaccines contain live virus and you CANNOT get COVID-19 from the vaccine. The immune response to the vaccine can give you symptoms such as fever and body aches. These typically last 1-3 days and then resolve. It takes at least 2 weeks for the body to develop immunity after vaccination. If you are exposed to COVID-19 just before or soon after vaccination, you could get sick with COVID-19 because you are not yet protected by vaccination.

Yes, it is advisable to receive the COVID vaccine even if one has had infection with COVID-19. The vaccine provides a stronger immune response against COVID than natural infection. Therefore, it is recommended to receive vaccine even after COVID-19 infection.
The MoHFW recommends waiting for 3 months after recovery from COVID-19 to get vaccinated. For more information, please visit: https://www.mohfw.gov.in/covid_vaccination/vaccination/faqs.html

Yes, as of July 2, 2021 the Union Ministry of Health and family Welfare (MoHFW) approved the vaccination of pregnant women against COVID-19.
Women may be vaccinated during any trimester of pregnancy with any approved vaccine.
See operational guidance (link to https://www.mohfw.gov.in/pdf/OperationalGuidanceforCOVID19vaccinationofPregnantWoman.pdf)for additional details including fact sheets, counseling of pregnant women and reporting of adverse events.

Pregnant women are at increased risk of complications from COVID-19 infection, and benefits from vaccine outweigh the risks.

Yes, all the COVID vaccines can be given to breastfeeding women. Neither the person who receives the vaccine nor the infant is harmed by the vaccine. Breastfeeding is NOT a contra-indication to vaccination

Yes, all the COVID vaccines can be administered to women who are menstruating. Menstruation is NOT a contra-indication to vaccination

-Content Created by

Pratibha Seshadri, MD
Medford, Oregon, USA
AND
Priya Sampathkumar, MD
Mayo Clinic, USA

Last Updated on June 2, 2021

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