The Different Coronavirus Vaccines – A Simple Breakdown

We were hesitant to write about the coronavirus vaccine, because we figured that your neighbor down the street has you covered on this issue.  He has no scientific knowledge, but he does express his views strongly on Facebook.  And since he uses a lot of capital letters and exclamation points, he’s probably right.  After significant consideration, however, we decided to take on the topic using certain resources such as this and this for guidance.  As a point of caution, these resources are compiled by people with years of training and expertise, so they may not be as reliable as your neighbor.  With that said, here’s a simple breakdown of the different coronavirus vaccines.

 

The Basics

There are many strains of coronavirus.  We’re talking specifically about SARS-CoV-2, the one that causes COVID-19.

In order to understand the different vaccine approaches, a few basic concepts are worth noting:

• DNA, the code for life, is transcribed into RNA (specifically messenger RNA, or mRNA).  The mRNA is then translated into protein.  Given this sequence of events, the presence of mRNA alone is sufficient to code for a protein.
• Viruses consist of genetic material (either DNA or RNA, both also called nucleic acids) that is surrounded by a shell of lipids and protein.  The protein in the shell is coded for by the genetic material.  In the case of SARS-CoV-2, the genetic material is RNA, and a key protein on the shell is called the spike protein.  This spike protein allows for attachment to and infection of human cells.  It is also called an antigen as it is important in triggering an immune response.

 

The Four Major Vaccine Types

Vaccines serve to prime the immune system for future attack by the actual disease-causing agent, in this case SARS-CoV-2.  This goal can be accomplished in four different ways.

Whole Virus Vaccines

In such a case, the entire virus is used in a vaccine.  One option is to use a weakened form of the virus in what is called a live attenuated vaccine.  The other option is to use a virus that has had its genetic material destroyed in what is called an inactivated vaccine.  (Such a virus cannot make copies of itself but can still trigger an immune response.)

Nucleic Acid Vaccines  

Such vaccines directly deliver genetic material (DNA or RNA) to human cells, thus providing the code for the cells to make the spike protein (but not the rest of the virus).  The spike protein then sets off an immune response.  The two vaccines in use in the U.S. utilize mRNA in this fashion (see below).

Protein Subunit Vaccines

These vaccines use pieces of proteins (typically the spike protein) to trigger an immune response.  Such immune responses tend to be weaker.

Viral Vector Vaccines

In this case, a harmless virus called adenovirus (totally different from coronavirus) is packaged with DNA that carries the same code as the SARS-CoV-2 RNA that codes for the spike protein.  This harmless virus “infects” cells with the DNA which is then transcribed to mRNA and ultimately translated to the spike protein that sets off the immune response.

 

Where We Are Now

Due to immense governmental funding and numerous public-private partnerships, effective vaccines have been successfully manufactured, tested, and authorized in a remarkably timely manner.  In fact, vaccines using all four approaches have been authorized worldwide.  In the U.S., as mentioned above, both vaccines that are being administered (Pfizer-BioNTech and Moderna) fall under the nucleic acid category.  Across the world, other vaccines using the whole virus, protein subunit, and viral vector approaches have been authorized.  As an example, the Oxford-AstraZeneca vaccine being used in the United Kingdom uses the viral vector approach.

 

Side Effects

Those with known severe allergic reactions to a specific vaccine’s ingredients should not receive that vaccine.  The two vaccines being used in the U.S. can be associated with injection site soreness, fevers, headaches, and body aches.  Such symptoms indicate that an immune response is occurring (i.e. the vaccine is achieving the desired result).  No vaccine described above integrates in any way with human DNA.  Will as yet unknown side effects make themselves apparent as more and more people receive the vaccines?  Possibly.  Will such side effects affect a tiny fraction of vaccine recipients?  Absolutely.

 

Unfortunately, the only obvious exit strategy from the current pandemic involves widespread vaccination.  In order to avoid staying in the current holding pattern indefinitely, moving forward seems like the strategy of choice.  But you may want to check with your neighbor first.