COVID-19 Vaccine

COVID-19 vaccines have been shown to reduce the severity of coronavirus (SAR-CoV-2) infections and hospitalizations.

Many pharmaceutical companies have made various COVID-19 vaccines. To put an end to the pandemic, people are being encouraged to accept the vaccine when offered.

Many high risk groups such as frontline health workers and older adults have been vaccinated during mass vaccination campaigns going on globally.

For the World to return to business as usual, countries need to achieve herd immunity, which translates to 70% of population vaccinated. This herd immunity reduces person-to-person transmission of the Coronavirus.

COVID-19 Vaccine

The first COVID-19 vaccine to be approved by the FDA was Pfizer-BioNTech in December 2020. This is a Messenger RNA (mRNA) vaccine. This vaccine is given 2 doses 3 weeks apart.

The mRNA works by stimulating T-cell mediated immune response and the production of antibodies. The mRNA works in the cytosol which is the fluid within the cell after which the cell degrades the mRNA. The mRNA does not enter the nucleus of the cell or alter the DNA of the cell. In response to the mRNA, the cells make spike protein, that block the coronavirus from infecting the cells.

The second mRNA vaccine approved in USA was by Moderna. This vaccine is given as 2 doses, 4 weeks apart.

The first dose of the mRNA typically has very few side effects with mostly pain at the injection site, that can last for up to 3 days.

The second dose of mRNA is more reactogenic, and can cause fever, fatigue, body ache and pain at the injection site. Symptoms typically resolve with rest, hydration with water, and tylenol or paracetamol.

People who have had anaphylaxis from components of the mRNA vaccine would be advised to seek counsel from their provider and avoid taking the mRNA vaccine.

Long term safety data is not available for the mRNA vaccine because this is the first time mRNA technology has been used to make vaccines. The technology to create mRNA vaccine has been studied for 20 years. During the COVID-19 pandemic, pharmaceutical companies were able to accelerate clinical trials by simultaneously working on different processes to produce the vaccines.

The non mRNA vaccines for COVID-19 have been made using traditional vaccine manufacturing processes as we have seen for the various existing vaccines. We know that vaccines are safe. People have received vaccines for various bacterial infections; examples of which are tetanus and pneumovax vaccines, and vaccination against viral infections such as influenza, polio and smallpox vaccines as examples.

Vaccines have been around since the first smallpox vaccine was produced in the 1790s. Since that time, advances in medicine and science have allowed vaccines to be safely produced. We know vaccines work and prevent disease.

COVID-19 VaccineTypeEfficacy against severe diseaseStorage of vaccine
Pfizer-BioNTechmRNA95%Ultra-cold freezer between
-80°C and -60°C (-112°F and -76°F)
ModernamRNA94.1%Frozen between -25º to -15ºC (-13º to 5ºF)
Janssen by Johnson and JohnsonInactivated virus particle86%Store at refrigerated temperature of 2°C to 8°C (36°F and 46°F). Do not freeze.
AstraZenecaInactivated virus particle100%Store at refrigerated temperature of 2°C to 8°C (36°F and 46°F).
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The third vaccine approved by FDA is by Janssen COVID-19 Vaccine by Johnson and Johnson. This vaccine works through inactivated virus particle which primes the body’s immune system to fight off the coronavirus. It is a one time injection.

In the UK, the AstraZeneca COVID-19 vaccine was approved in December 2020, as a 2 dose injection given 4 to 12 weeks apart. The vaccine is made using inactivated virus particle.

There are many more vaccines that have been approved in different countries.

Currently, over 300 million vaccines have been given globally across over 110 countries.

Written by Dr. Onuoha.

Dr. Onuoha received a first dose of PfizerBioNTech vaccine in December 2020, followed by a second dose in January 2021.

Disclaimer: This post serves as medical education for a general audience. This is not medical advise. Information data can change at anytime.

Additional resources:

https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/covid-19-vaccines

https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-02/28-03-01/02-COVID-Douoguih.pdf

https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(20)30773-8.pdf

https://www.astrazeneca.com/media-centre/press-releases/2021/covid-19-vaccine-astrazeneca-confirms-protection-against-severe-disease-hospitalisation-and-death-in-the-primary-analysis-of-phase-iii-trials.html

https://www.yalemedicine.org/news/covid-19-vaccine-comparison

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