COVID Vaccine

  • by VaccineHealthCenter

December 2019 to December saw a steady increase in the new infection and death cases related to Covid-19. Shortly after the pandemic struck, health agencies set on working tirelessly to develop vaccines that could offer protection against the Covid-19 disease. The result has seen vaccines being introduced and as of 21st February, 175.3million doses had been administered using seven vaccines on three platforms.

What are the Covid vaccine types?

So far, World Health Organization (WHO) has issued an Emergency Use Listing (EUL) for three vaccines since the strike of the Covid-19 pandemic. The following are the Covid vaccines approved for use by the WHO;

  • Pfizer/BioNTech – this was the first Covid-19 vaccine to be approved by the WHO to be used. It can be used on individuals who are sixteen years and older. Medical practitioners offer the vaccine in two shots, with 21days between the first shot and the second. It is two weeks from the final shot of that PfizerBioNTech Covid-19 vaccine that the vaccine starts being effective. WHO gave Pfizer/BioNTech vaccine a EUL on 31st December meaning the vaccine has been used to offer protection against Covid for some three to four months.
  • Moderna – this is another Covid-19 vaccine approved by the WHO for use. Unlike the Pfizer/BioNEch that is used in people who are sixteen years and older, the Moderna vaccine can only be administered by health practitioners on people who are eighteen years and older. Like Pfizer, Moderna is administered in two shots. Between the first and the second shot, there is a period of twenty-eight days. It is only two weeks after the second shot that the Moderna vaccine becomes effective.
  • Johnson and Jonson’s Jassen vaccine- this is a Covid vaccine that is administered to people whose ages are eighteen years and above. Unlike the other vaccines, Johnson & Johnson’s Janssen is administered two the recipient once. Once the vaccine has been introduced to the body, it takes two weeks from the time of the vaccination for the vaccine to fight Covid-19.

For these vaccines, there is no particular one that the CDC prefers over the other. This means that as a doctor you are not entitled to choosing the form of vaccine for your patients. A patient takes the responsibility and the risks associated with the vaccine. Consequentially, he makes the choice himself without your input. All you do as a doctor is to explain to the patient the various types of vaccines available and the technologies used, as well as any other critical information about the virus.

The technologies applied in making the Covid-19 vaccine

For each of the above vaccines, a specific technology was employed in creating the vaccine. Here are the two technologies applied by the medical agencies to create the vaccines;

  • mRNA technology- this is the technology that has been used in developing Pfizer/BioNTech and the Moderna Covid-19 vaccines. In this technology, a live or attenuated form of the infectious coronavirus is not introduced in the body. Instead, the mRNA is used to deliver special instruction cells to the immune system. The instruction cells work by triggering the type B cells to produce antibodies. These antibodies protect the body against Covid-19 infection upon interacting with the virus in the future.
  • Viral vector technology- this is the technology that Johnson & Johnson’s Janssen company applies to produce its Covid-19 vaccines. Unlike the mRNA technology, the viral vector technology involves the introduction of the viral vector of the coronavirus into the body in the form of a vaccine. The vector, once in the cells, uses the cell's machinery to produce a harmless virus that causes Covid-19. The piece is harmless piece is called a spike protein and it usually occurs on the surface of the Covid-19 causing virus. The body then recognizes the foreign spike and stimulates the type B cells to produce antibodies. These antibodies protect the body, reducing the risk of contracting Covid-19 upon actual interaction with the infectious coronavirus.

The stages of Covid vaccine development
To create any of the Covid-19 vaccines, a series of stages show below were followed;

  • Determining how the vaccine will work-this stage takes up to four years and involves finding the antigen(s) that when introduced to the body will cause trigger the body the way an actual pathogen (like the infectious coronavirus) would do to produce antibodies.
  • Phase 1/2a and 2b- this stage involves giving the vaccine to 20 to 80 people to determine its effectiveness and the immune response it would generate
  • Phase 3- this is the phase where more volunteers go for the vaccine to find out whether it is really effective
  • Regulatory approval and licensure- this is when the vaccine manufacturers submit an application to the regulatory bodies for a safety test, approval, and licensing
  • Regulatory monitoring- even after the vaccine is proven safe, the regulatory bodies keep monitoring the vaccine to see whether it will stay down the road

Side effects of the Covid-19 vaccines
One of the negative side effects of the Covid vaccines is the life-threatening reaction called anaphylaxis. This is normally characterized by several signs, including shock, wheezing, confusion, difficulty breathing and swallowing, abdominal pain, and slurred speech among other signs. CDC recommends people with a history of allergy not take the vaccines. If they have to, there are other guidelines the vaccine provider has to apply.


This article has discussed the types of Covid-19 vaccines, technologies used in the manufacture, the clinical stages followed in development, and the negative side effects. You might find this information crucial in advising your patients.