Does my MS medication affect my ability to respond to vaccines?

Image: Fusion Medical Animation on Unsplash

Background:

Our immune system includes a type of cell called lymphocytes. T lymphocytes target other cells such as cells infected with viruses or cancerous cells. They are called “T” cells since they mature in the thymus gland in the upper chest. Normally T cells that would attack our own cells are destroyed in the thymus gland before being released into the circulation. In autoimmune diseases such as multiple sclerosis, these T cells escape and can lead to the immune attack on myelin.

B cells mature in the bone marrow in humans, but were named after a specialized organ where B cells mature in birds known as the bursa of Fabricius. B cells can change into plasma cells which make antibodies. Antibodies are like targeted arrows that can help attack germs such as viruses or bacteria that are invading our bodies. In multiple sclerosis, B cells turn against their human by creating antibodies that attack myelin and revving up autoimmune T cells.

Role of T and B cells in Vaccination:

Vaccines work by imitating a serious infection. Vaccines can cause minor symptoms, but do not cause the actual disease. The vaccine triggers the development of specific-targeted T and B cells that remember the infection. When someone is then exposed to the real life-threatening virus or bacteria in the future, they can mount a highly effective defense against the infection due to these “memory” T and B cells. For example, children are vaccinated with a weakened, live chicken pox virus called the varicella-zoster virus. The immune system then develops T cells and antibodies specific for this varicella virus. The vaccine has been shown reduce the risk of getting chicken pox later in life by 92%. If someone is immunosuppressed, important to avoid live, weakened (attenuated) viruses.

Most vaccines are inactivated vaccines which means they do not contain live viruses or bacteria. Vaccines that inject killed whole virus include polio, hepatitis B and rabies.  Many inactivated vaccines include only sugar molecules (polysaccharides) that are found on the surface of bacteria or surface proteins that are found on viruses. These components of the infectious agent lack the ability to replicate since they do not contain disease-spreading genetic material (RNA or DNA).

COVID-19 vaccines:

For COVID-19, the Pfizer and Moderna vaccines are mRNA vaccines. The mRNA contains instructions for our own body to make a harmless “spike” protein.  This spike protein is on the surface of the COVID-19 virus. The spikes on the surface of this COVID-19 coronavirus creates a “corona” (derived from the latin word for crown).  The mRNA is surround by a lipid (fatty) nanoparticle that allows it to enter cells of the body when injected in the muscle.  Once mRNA is in the cells, the cells can create their own spike proteins on their surface. The body’s immune system that reacts to these foreign spike proteins leading to immunity with memory T and B cells.  These COVID-19 vaccinations result in a robust immune response to this spike protein that provides up to 95% immunity from the real COVID-19 infection, caused by the SARS-CoV-2 virus.

The AstraZeneca and Sputnik V vaccines use a type of virus called an adenovirus to insert DNA into the cell nucleus.  The double-stranded DNA does not get into our own DNA, however.  The DNA strand allows the cell to also make only the spike protein.  The DNA in the adenovirus has been altered so the adenovirus lacks to the ability to replicate (divide) in the body.