Roman Life: Harbin Clinic’s Dr. John Hostetler breaks down the different types of COVID.

A weekly column addressing your most sought-after health questions, answered by Harbin Clinic’s expert healthcare professionals.

Question: What are the different types of COVID-19 vaccines available?

Dr. John Hostetler: The purpose of all vaccines is to stimulate an immune response against organisms that would do us harm. This requires exposing our immune system to key proteins that are crucial in producing this response.

Scientists already knew from other deadly coronaviruses (SARS, MERS) that the spike proteins on the surface of this virus hold the key to that response. MRNA teaches a few of our cells to make this spike protein without any risk of altering our own DNA or exposing us to a live virus. Once that protein is made, the MRNA, along with the other stabilizing components of the vaccine, are cleared from our body leaving us only with a defense system to counter future attacks from this virus. This is how the Moderna and Pfizer vaccines work.

The Johnson & Johnson vaccine shares with MRNA vaccines the ability to “instruct” certain cells to produce spike proteins on their surfaces to generate an immune response. These instructions are provided as a small segment of DNA contained within a modified cold virus (adenovirus).

This virus delivers the DNA to our cells, but it is incapable of reproducing itself in our body and it cannot alter our own DNA. This DNA produces MRNA to then instruct our cells to produce spike proteins, as with the Moderna and Pfizer vaccines. All the components of the Johnson & Johnson vaccine include the adenovirus. The DNA and MRNA segments are immediately broken down after the spike protein is produced with no lasting components. This method has been in wide use for an Ebola vaccine in Africa and has proven to be quite safe and effective. The Astrazeneca vaccine works in a similar manner with a different adenovirus.

We are pleased to now offer the COVID vaccine to Harbin Clinic patients 18 years of age and older. Visit our website to schedule your appointment. Dr. John Hostetler is a board-certified Infectious Disease physician at Harbin Clinic Infectious Disease Rome. To learn more, visit

harbinclinic.com/infectiousdisease.