Many wonder if the seasonal flu vaccine contains messenger RNA (mRNA), especially with recent vaccine technology advancements. Understanding the components of different vaccine types is important for public health. This article clarifies the distinctions between traditional flu vaccines and mRNA technology.
The Simple Answer
Traditional seasonal flu vaccines do not contain mRNA. These vaccines utilize established methods to prepare the immune system against the flu virus. While mRNA technology is a newer development in vaccine science, it is not currently used in the widely available flu shots.
What Traditional Flu Vaccines Contain
Standard flu vaccines introduce influenza virus components to the immune system, prompting a protective response. Most flu shots contain inactivated virus particles or specific viral proteins like hemagglutinin (HA) and neuraminidase (NA). These antigens are surface proteins the immune system learns to recognize. Some flu vaccines contain a weakened, live virus, like the nasal spray vaccine.
Beyond viral components, flu vaccines contain other ingredients for safety and effectiveness. These can include:
- Sodium and potassium salts as acidity regulators.
- Polysorbate as an emulsifier.
- Stabilizers like gelatin or amino acids.
- Preservatives, such as thimerosal in multi-dose vials, to prevent bacterial contamination.
- Small amounts of antibiotics like neomycin or kanamycin to inhibit bacterial growth during manufacturing.
- Formaldehyde, used during production to inactivate viruses.
Understanding mRNA Vaccine Technology
Messenger RNA (mRNA) vaccine technology offers a different immunization approach. Instead of introducing viral proteins or inactivated viruses, mRNA vaccines deliver genetic instructions to cells. These mRNA instructions teach cells to produce a harmless viral protein, like the SARS-CoV-2 spike protein. Once these proteins are made, the immune system recognizes them as foreign and initiates a protective response, including the production of antibodies.
The mRNA in these vaccines does not enter the cell’s nucleus, where DNA is stored, and does not alter genetic material. mRNA molecules are temporary and quickly broken down by the body’s natural processes after delivering instructions. This technology allows for rapid design and production of vaccines, as it does not require growing large quantities of viruses.
Why the Confusion About Flu Vaccines and mRNA?
Public awareness and questions about mRNA in flu vaccines largely stem from the rapid development and widespread use of mRNA-based COVID-19 vaccines. Before the COVID-19 pandemic, mRNA vaccine technology, though researched for decades, was not widely known. The success and speed of COVID-19 mRNA vaccines brought this technology into the global spotlight, leading many to wonder if it was incorporated into other common vaccines, like the annual flu shot.
Despite mRNA technology’s prominence in newer vaccines, traditional seasonal flu vaccines continue using established methods. While research for mRNA-based flu vaccines is ongoing and some candidates are in clinical trials, they are not currently approved or widely available. This distinction between traditional flu vaccine formulations and newer mRNA platforms causes much of the confusion.