Aimee Seidman, MD, FACP
Influenza vaccine is recommended for everyone over 6 months old. It reduces influenza cases and the risk of serious complications and death associated with influenza.
Many people think they “get the flu” from the flu shot. Since the vaccine is not live, it cannot create disease. The body is “fooled” into thinking it is infected with the flu, and the mild side effects are the manifestation of this. If your symptoms last longer than 48-72 hours, you probably have a different virus unrelated to the shot.
What is the difference between the common cold and influenza? A lot of people use the word “flu”, but it can mean either the cold or influenza. Influenza frequently presents abruptly and is associated with high fever and prominent systemic symptoms, including muscle aches, severe headaches, and profound fatigue. The common cold is much more frequent. It frequently presents gradually, with predominantly nasal congestion and even significant fatigue. That fatigue and malaise can last quite a while, especially in older adults. You can feel terrible with the common cold. There is plenty of overlap, however, and sometimes it’s difficult to figure out. There is no cure for the common cold, but we can address some symptoms, such as postnasal drip and a mild cough. The diagnosis of influenza requires a test. If positive, we will often use the drug Tamiflu (oseltamivir) in people who are quite sick.
Those younger than 65 (without a contraindication) should receive one of the standard vaccines, Fluarix, Flulaval, Fluzone, Fluad, Flucelvax, or Flublock. They are all effective. I recommend that you take the one available at your pharmacy. I carry the Fluzone, which is fine for anyone under 65. For patients over 65, a higher dose flu vaccine is recommended. This is the Fluzone High Dose. If only the standard dose is available, that vaccine is acceptable. Is a higher dose not available for the other 5 standard vaccines? The mRNA vaccine MFlusiva is recommended for adults aged 50 and older, so it is an option.
Pregnant women should get the flu shot to protect their infants. The nasal vaccine, Flumist, is not recommended for pregnant women.
Those patients with an egg allergy of any severity are not at risk from egg-based influenza vaccines. Numerous studies have shown that people with egg allergy are not at risk for an adverse reaction to influenza vaccines made with egg.
Immunocompromised patients need the flu vaccine, but not the live nasal vaccine (Flumist). The other vaccines are safe, though the mRNA vaccine has not been adequately studied in immunocompromised individuals.
Influenza vaccines can be administered at the same time as the COVID vaccine but should be given in different arms. RSV vaccines can also be combined with the others, but antibody levels are somewhat lower than if they were given one month apart.
Adverse reactions from the flu shots can include soreness, fatigue, headache, and muscle aches. Elevations of glucose can occur in diabetics, but these should normalize within 1-2 days. Higher dose vaccines may cause more of these side effects. The mRNA vaccine can cause more frequent side effects. The live nasal vaccine (Flumist) may cause runny nose, nasal congestion, fever, and sore throat.
Guillain-Barré syndrome is a very rare side effect of the vaccine, but the risk of influenza is much higher, so the benefits of getting the vaccine far outweigh the risks. Inflammation of the heart has been reported rarely following the second dose, and mainly in young men. Again, the risk of this side effect pales in comparison to the frequency of influenza.
Flu shots should be given in October/November, so that the immunity lasts long enough to cover most of the season.
