What is the difference between the Moderna, Pfizer and J& J vaccine?

What is the difference between the Moderna, Pfizer and J& J vaccine?

The first vaccine that was approved in the United States was the Pfizer mRNA (messenger RNA) vaccine.  It is now fully FDA approved in all patients aged 12 and older.  It is marketed under the brand name Comirnaty®. Messenger RNA vaccines deliver instructions to the cell to make a tiny protein on the surface of the cell that resembles the spike protein that the COVID-19 virus has on its outer surface.  This spike that the vaccine creates does nothing, and you cannot get COVID-19 from this protein segment.  The spike protein found on the actual coronavirus is how the virus attaches to the cell and starts the infection. Once your immune cells see this foreign protein, they create antibodies to destroy the protein.  These antibodies will also attack the COVID-19 virus if you are exposed to the virus. And that’s how it helps prevent serious infection if you are exposed.

Scientists have been working on mRNA technology since the 70’s.  The advantage of mRNA vaccines is they don’t have to be cultured or grown to produce the vaccine. The challenge has been to develop the carrier to deliver the delicate mRNA to the cells before the body destroys it.  This new development will be used in many vaccines in the future and possibly cancer treatments. 

Last month Pfizer also received emergency use authorization for their pediatric version of the vaccine.  It can be given to children ages 5-11.

Moderna is also a mRNA vaccine and works very similar to the Pfizer vaccine.  It has emergency use authorization for all patients 18+ years old. They both have been proven to be safe and effective.  Both require two vaccinations to reach 95% protection.  Immune response to any disease naturally diminishes with time.

J&J (Janssen) vaccine uses a more traditional method of delivering the instructions to the cell. Instead of using mRNA, the Johnson & Johnson vaccine uses a disabled adenovirus to deliver the instructions to a few of your cells to also grow spike proteins, like the other two vaccines. This adenovirus carrier is not related to the coronavirus. It is a completely different virus.  This vaccine was initially promoted as a “one and done” vaccine. And it helps patients prevent infection approximately 70% of the time.  It has emergency use authorization for all patients 18+ years old

Since these vaccines were introduced, the virus has mutated, and the prevalent delta variant is much more contagious than the strains that were around a year ago.  Coming in close contact with a person that has an active infection can overwhelm your immune system at the point of attack. Good immunity requires multiple layers of antibodies and by getting an additional dose of any of these vaccines boosts your immune system. A robust immune system, strengthened by an additional dose of your chosen vaccine is more effective at blocking the delta variant infection.

So currently it is recommended that all vaccinated individuals consider an additional dose.  With Pfizer the 3rd dose is like the first two and it is given 6 months after the 2nd dose. 

Moderna booster is half strength, and it is also given 6 months after the 2nd dose.

J&J vaccine booster is full dose given 2 months after the first dose.

People are allowed to mix and match their vaccine based on availability, adverse reactions, or personal preferences.  Many vaccines used today are given in multiple doses to maximize your immunity - for example the Polio and pneumonia vaccine. It is likely that these additional Covid-19 vaccine doses may be simply part of the vaccine treatment guidance.

As of November 2021, more than 7.8 billion doses of these vaccines have been given worldwide. These vaccines are proven to be extremely effective.  Although no vaccine is without possible side effects - but most are minor.  This vaccine is only in your body for about 4 days before your body destroys it. Your body creates an immune response, and then your immune system wipes it out.  Potential adverse effects of a COVID-19 infection are many times greater than the vaccine side effects and can trigger long term complications and death.

Studies show people with a previous COVID-19 infections are 5 times more likely to get a second COVID-19 infection than a vaccinated person.  The key with these vaccines is their ability to create immunity to the virus’s spike protein.  It is difficult to know if a naturally acquired immunity from previous COVID-19 infection targets spike protein. This unknown make variants more likely to cause a 2nd infection.  I strongly recommend everyone age 5 and older get fully vaccinated and, in most situations, get a booster dose when it is recommended.

Detailed information on any vaccine can be found at www.CDC.gov.