COVID19 Vaccines

This is an ever-evolving topic, but I thought I would give you an overview of the available adult COVID19 vaccines for this snapshot in time.  

The currently available COVID-19 vaccines in the US are produced by Pfizer, Moderna, and Johnson & Johnson.  The Pfizer and Moderna vaccines are mRNA vaccines, meaning the mRNA is translated into a target protein, which then causes an immune response in your body.  If you remember from your biology classes in high school, this translation of mRNA happens outside of the nucleus in the cell cytoplasm.  This means there is no interaction of the RNA with the vaccine recipient’s DNA.  The Johnson & Johnson vaccine is an adenoviral vector vaccine.  This means an adenovirus is used to present a SARS-CoV-2 protein to the body and stimulate an immune response.  Because almost all of us have been exposed to adenovirus (one of the viruses that can cause a cold), the immune response is not quite as robust as the mRNA vaccines.  Studies are evolving (especially with the introduction of other variants), but the effectiveness of these vaccines against COVID19 related hospitalization was 93% for the Moderna, 88% for Pfizer, and 71% for J&J (1).  Dosing details are as follows. 

·      Pfizer vaccine mRNA dose is 30mcg, given in two doses 21 days apart.  For certain immunocompromised patients, a third dose is given at least 28 days after the 2nd dose.  Booster dose is given 6 months after the last vaccine and dose is also 30mcg. 

·      Moderna vaccine mRNA dose is 100mcg and two doses are given 28 days apart.  For certain immunocompromised patients, a third dose is given at least 28 days after the second.  Booster dose is given 6 months after the last vaccine and dose is lower than the primary series at 50mcg. 

·      J&J vaccine is one dose for the primary series and a booster is recommended at least two months after the initial vaccine. This vaccine was marketed as one and done, but immunity is improved with the 2 dose series and likely should really be two doses as a rule.

The boosters are now available to all adults 18 years and older and are available at most pharmacies. Of note, the mix and match approach can be used for the booster dose where either mRNA vaccine can be given without regard for the type of initial dose.  For example, for those who received J&J for their initial vaccine, it is reasonable to have a mRNA vaccine as a booster. 

You are always welcome to touch base with us if you have questions about the COVID19 vaccines or boosters.  

References

1)    Thompson MG, et al.  Effectiveness of Covid-19 Vaccines in Ambulatory and Inpatient Care Settings.  NEJM.  2021;385 (15):1355. Epub 2021 Sep 8. 

2)    Edwards KM and Orenstein WA.  COVID-19: Vaccines to prevent SARS-CoV-2 infection.  Available on UpToDate. Updated 11/4/2021.