What You Should Know About the New mRNA Flu Vaccine 
According to PCOM South Georgia Experts

Stacie Fairley, PhD, associate professor of microbiology and immunology, compares the technology to a fire drill.

“Messenger RNA, or mRNA, is a temporary set of instructions that tells cells how to make proteins,” she said. “An mRNA flu vaccine uses those instructions to prompt cells to produce a harmless protein that resembles part of the flu virus. The immune system then recognizes that protein and learns how to respond if it encounters the actual virus in the future.”

She goes on to say that this allows the immune system to practice responding to the flu without facing the danger of an actual infection, and that this new technology could offer a more effective approach to developing seasonal flu vaccines.

“Influenza viruses continually change, and manufacturers must predict circulating strains months before flu season begins. If those predictions do not closely match the viruses that eventually circulate, protection may be reduced.”

According to the FDA, side effects reported in clinical trials of mFLUSIVA included injection-site pain, fatigue, headache, muscle or joint aches, chills, nausea or vomiting, fever, and temporary swelling or tenderness of the lymph nodes under the arm of the injection site.

Dr. Fairley states that most reactions are mild to moderate and resolve within two days. She also addressed common misconceptions about mRNA vaccines, including concerns that they can alter DNA.

“mRNA vaccines cannot change your DNA because they cannot enter the nucleus, where DNA is stored.” It does not stay in the body permanently, because it breaks down after delivering its instructions.”

Winston Price, MD, FACPE, associate professor of pediatrics, says the mRNA flu vaccine is not currently approved for children, although children have received other mRNA vaccines.

“Children have received COVID-19 mRNA vaccines with excellent effectiveness and safety in the past,” he said. “Newer mRNA vaccines are currently being evaluated for children because the mRNA technology can help them design and update vaccines faster without using live or dead viruses.”

The new mRNA influenza vaccine is not currently recommended for routine use during pregnancy, according to Matthew Shelnutt, DO, FACOOG, director of patient care skills and assistant professor of obstetrics and gynecology. “This recommendation is specific to the new influenza vaccine and should not be interpreted to mean that mRNA vaccines are generally unsafe during pregnancy,” Shelnutt said. “Pregnant patients should speak with their healthcare provider about the influenza vaccine and other vaccines that are appropriate for them during pregnancy.”

Currently, inactivated or recombinant influenza vaccines are the recommended flu vaccine options during pregnancy.

Matthew L. Holt, PharmD, BCPS, assistant professor of pharmacology, advises adults 50 and older to ask their pharmacist or physician which influenza vaccine is most appropriate given their age, comorbidities and prior vaccine reactions.

“For adults 50-64, the CDC does not indicate a preference for one influenza vaccine formulation over the other,” Holt said. “However, it should be noted that the CDC does preferentially recommend one of three formulations for patients 65 years of age or older. These include Fluzone High Dose, Flublok recombinant vaccine, or Fluad adjuvanted vaccine.”