COVID19 is a serious infectious disease that is caused by a new coronavirus. People who suffer from this virus experience mild to moderate respiratory illness and recover without any special treatment. Older people and those who suffer from underlying medical conditions like cardiovascular disease, diabetes, chronic respiratory disease, and cancer are more likely to develop serious illnesses. The mass vaccination process for COVID 19 disease started in 2020. Currently, four vaccines are authorized and recommended by the WHO: AstraZeneca, Pfizer, Moderna, and Janssen (J&J).
What is AstraZeneca?
AstraZeneca is a DNA vaccine used against COVID 19 disease. AstraZeneca company collaborated with Oxford University to make this vaccine in 2020. It shows 90% efficacy against COVID 19 disease. Through this vaccine, the genetic instructions are given to the cell to make the spike protein of the COVID19 virus, which stimulates the immune response in humans. In this vaccine, DNA is actually used as the genetic instruction to trigger the cell to make the spike protein. AstraZeneca vaccine uses a different approach to introduce its genetic instruction into the cell. Therefore, this vaccine uses adenovirus, which normally infects chimpanzee as a vector to deliver DNA into the cell.
The genetic instructions are inserted into the adenovirus vector for making the SARS COV2 spike protein. The adenovirus infects the human cell and delivers the DNA into the cytoplasm of the human cell. The cell recognizes the DNA material and places it in the nucleus. The ribosomes transcribe the instruction set to make the spike protein. Then the spike protein causes the immune response to make antibodies and activates T cells, B cells, etc.
What is Pfizer?
Pfizer is an mRNA vaccine used against COVID-19 disease. This vaccine was made by Pfizer-BioNTech company in 2020. It is also called “Tozinameran or BNT162b2”. This vaccine is approved for people who are 12 years of age or older. Health Canada first authorized this vaccine with conditions in December 2020. The vaccine uses an mRNA that human cells read to make proteins. To protect the mRNA vaccine, Pfizer-BioNTech wraps the mRNA in oily bubbles made of lipid nanoparticles before delivery to the cell.
The cell reads the mRNA sequence and builds spike proteins. Then the mRNA from the vaccine is eventually destroyed by the cell. Later, these spike proteins are recognized by the immune system. This causes immune responses (antibody production and T cell and B cell activation) and protection from COVID19 infection in future. Pfizer mRNA vaccine has a 95% efficacy. Furthermore, this vaccine should be stored in an ultra-cold freezer between -80 °C and -60 °C temperatures.
What are the Similarities Between AstraZeneca and Pfizer?
- Both are types of vaccines.
- They are both used against the COVID19 virus.
- Both have approximately 90% efficacy.
- These vaccines use genetic material such as DNA or mRNA.
- They show side effects.
What is the Difference Between AstraZeneca and Pfizer?
AstraZeneca is a DNA vaccine used against COVID19 disease. Pfizer is an mRNA vaccine used against COVID19 disease. So, this is the key difference between AstraZeneca and Pfizer. Furthermore, AstraZeneca can be stored in normal refrigerator temperatures, such as between 36 °F and 46 °F. In contrast, Pfizer should be stored in sub-zero temperatures, such as between -4 °F and -94 °F.
The below infographic tabulates the differences between AstraZeneca and Pfizer vaccines for side by side comparison.
Summary – AstraZeneca vs Pfizer
There are many vaccines simultaneously in the pipeline for COVID 19 infectious disease. AstraZeneca and Pfizer are two vaccines that are listed in the WHO emergency use listing (EUL). AstraZeneca is a DNA vaccine, while Pfizer is an mRNA vaccine used against COVID19 disease. So, this is the summary of what is the difference between AstraZeneca and Pfizer.
1. Smith, Jake. “Here’s How the AstraZeneca COVID-19 Vaccine Compares to Those Available in the U.S.” Prevention, 3 May 2021, Available here.
2. “Pfizer-BioNTech COVID-19 Vaccine Overview and Safety.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, Available here.
1. “COVID-19 AstraZeneca Vaccine vial and NHS record card” By Rwendland – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Pfizer-BioNTech COVID-19 vaccine (2020) D” By U.S. Secretary of Defense – (CC BY 2.0) via Commons Wikimedia