Pfizer & Moderna vs. Johnson and Johnson — Vaccine Comparison
The overview for this article will be discussing the major differences between the Pfizer and the Moderna vaccines vs. the Johnson and Johnson vaccine. We will go over the
Mechanism
Distribution
Effectiveness
Pfizer and Moderna are mRNA vaccines whereas J&J is what is known as a recombinant vector. What does this mean?
Mechanism
mRNA Vaccine - Pfizer & Moderna
What is mRNA? Well to start, let's look at mRNA and how it works in the coronavirus itself. mRNA is located inside of the virus and is essentially the blueprint instructions on how to create proteins that the virus needs to thrive and replicate. In the context of COVID19, the mRNA creates an antigen (or a protein) that is expressed on the viruses surface, which is known as its spike protein. This spike protein is used by COVID 19 to attach to specific cells in our bodies and ultimately allows it to replicate inside our own cells.
So, a quick summary of mRNA in the coronavirus
mRNA inside cells—> Proteins. These proteins—> present on the surface of the cell in the form of spike proteins which allows it to attach to our human cells leading to infection.
Now us as humans, we all have mRNA in all of our cells that allow us to create specific proteins we need to survive. What the COVID 19 vaccine does is it uses a synthetically made, mimicked version of the COVID mRNA blueprint, which, once injected, gets taken up by our cells and allows our body to create our own versions of these spike proteins. NOTE: this does not actually effect the DNA within your cells. Our immune system will recognize these spike proteins as foreign and produce antibodies against them. So when the real virus is introduced with its own spikes, the body's immune system will know how to kill the corona virus before it can replicate high enough to cause infection.
Now this differs from the J&J vaccine which is a recombinant vector vaccine
Recombinant Vector - J&J
The recombinant vector vaccine takes a common cold virus, in this case adenovirus, and modifies it with new genetic code that is similar to the genetic code of COVID19, specifically the portion that is involved in making the spike proteins. Now this adenovirus is modified, so it can't actually cause harm once given, but it does allow the body's immune system to create antibodies against the spike proteins the adenovirus creates.
Mechanism Differences In Summary
So the major difference is the mRNA vaccines (Pfizer and Moderna) takes the genetic code of COVID19, putting that into your body, and allow you own cells to make those spike proteins providing immunity and the recombinant vector vaccine (or J&J) uses a different virus with an altered genetic code that's similar to COVID19s to make the spike proteins that way which leads to immunity. So the end result of immunity is actually very similar whereas you create antibodies towards spike proteins that are similar to COVID19s, but the means is a little different.
Distribution
Storage: Johnson and Johnson can be stored for up to 3 months at regular refrigerator temperatures where as Pfizer and Moderna have to be stored at much cooler temperatures. This allows J&J to have a wider spread of distribution reaching those in more rural communities.
Dose: The Johnson and Johnson vaccine is only a single dose vs the others, which are 2 doses. This is actually hugely important because experts have concluded so far that about 20-25% of all individuals that have gotten the first dose of another vaccine have not received the second (hard to track down), which provides complete immunity
Efficacy
Pfizer and Moderna have overall efficacy rates of 95 and 94 percent respectively. Johnson and Johnson has an overall efficacy rate of about 66%, however, all three of these vaccines have an efficacy of 100% in terms of stopping COVID from sending you to the hospital and potentially killing you. I go into more depth about this topic in another article, so if you’re interested, you can find it HERE.
