The development of COVID-19 vaccines raised many public questions, especially about how these new technologies interact with our bodies. A common inquiry is whether these vaccines can alter our DNA. This concern arises from a natural curiosity about how modern medicine, particularly involving genetic material, functions within human biology. Understanding the basic science behind these vaccines clarifies their mechanisms and addresses these questions.
Understanding Basic Genetic Material
Our bodies rely on two main types of genetic material: DNA and RNA. DNA, or deoxyribonucleic acid, serves as the long-term blueprint for all proteins our cells need to function. It resides within the nucleus of nearly every cell, organized into chromosomes. This double-stranded molecule is highly stable, making it ideal for storing genetic information across generations.
RNA, or ribonucleic acid, acts as a temporary messenger molecule. Unlike DNA, RNA is single-stranded and less stable, suiting its role as a transient carrier of instructions. Messenger RNA (mRNA) carries genetic instructions from DNA in the nucleus to ribosomes in the cytoplasm, where proteins are assembled.
How mRNA Vaccines Operate
mRNA vaccines, such as those by Pfizer and Moderna, introduce synthetic messenger RNA into our cells. This vaccine mRNA contains instructions for making a harmless piece of the virus, the SARS-CoV-2 spike protein. Once injected, the vaccine’s mRNA is taken up by our cells.
Inside the cell’s cytoplasm, ribosomes read these mRNA instructions to produce the spike protein. This process occurs entirely outside the cell’s nucleus, where our DNA is stored. The immune system recognizes these spike proteins as foreign and begins to produce antibodies and T-cells, preparing the body to fight future infection. The vaccine mRNA is temporary and degrades within a few days, without ever entering the nucleus or interacting with our DNA.
How Viral Vector Vaccines Operate
Viral vector vaccines, like those by AstraZeneca and Johnson & Johnson, employ a different approach to deliver genetic instructions. These vaccines use a modified, harmless virus, an adenovirus that cannot replicate, as a “vector” or delivery system. This modified virus carries DNA instructions for the SARS-CoV-2 spike protein into human cells.
After the viral vector enters a cell, it releases its DNA into the cell’s nucleus. The cell then uses these DNA instructions to create mRNA, which directs spike protein production in the cytoplasm, similar to how mRNA vaccines work. While the viral vector’s DNA enters the nucleus, it does not integrate into the human genome. The viral DNA remains separate from our own DNA and is eventually broken down by the body, ensuring it does not alter our genetic code.
Addressing DNA Integration Concerns
Concerns about COVID-19 vaccines altering human DNA are understandable but not supported by scientific evidence. Neither mRNA nor viral vector vaccines integrate their genetic material into the host’s DNA. mRNA vaccines deliver instructions to the cytoplasm, distinct from the nucleus where our DNA resides. The mRNA is short-lived and rapidly degrades after protein production, preventing long-term interaction with cellular components.
Even though viral vector vaccines introduce DNA into the nucleus, this DNA does not merge with the human genome. Unlike certain viruses like HIV, the viral vectors used in these vaccines lack the specific enzymes, such as reverse transcriptase, necessary to insert their genetic material into our DNA. Therefore, the genetic material from both types of vaccines is temporary and naturally cleared from the body without modifying our permanent genetic makeup.