Can the Flu Vaccine Give you the Flu?
Flu Vaccine Background
Yearly flu vaccinations may not be the most enjoyable doctor/pharmacy visit we have throughout the year. This may perhaps be due to a variety of reasons including the very common fear of needles, or the idea that the flu vaccine will give you the flu. It is important to understand the contents of a flu vaccine, the mechanism of action, and what exactly to expect from this immunization.
Flu vaccines are commonly administered in the deltoid muscle in the upper arm, but they can also be administered in the lateral muscle of the thigh (1). The muscle is the preferred site of administration because of its rich blood supply which will allow the body to build its immunity against the virus quicker. Muscle soreness at the injection site is a common side effect from vaccinations because of the nature of the needle breaking through the fibers of the muscle. This will typically resolve within two days from the vaccine. Other contributors to pain may be due to not eliminating the air bubble in the syringe or the cold temperature of the vaccine which is required to be stored under refrigeration.
Allergies are also important to be noted before the first flu vaccination. Some of the contents of these vaccines can trigger an allergic reaction for some patients that may have an allergy to one or more of its contents. These vaccines contain preservatives, antibiotics, gelatin, egg proteins, and other contents that are intended to keep the solution stable as well as increase its efficacy when administered. Therefore, to prevent an allergic reaction, patients are required to provide pertinent information about their allergies prior to vaccination.
Furthermore, the vaccine relies heavily on our immune system to carry out its intended purpose of offering immunity.
Flu vaccines come in a variety of preparations (2):
Inactivated – uses the killed version of the virus that causes certain strains influenza
Live Attenuated – a weakened (attenuated) form virus that causes certain strains influenza
Recombinant – egg free
Trivalent – protects against 3 different strains of the virus
Quadrivalent – protects against 4 different strains of the virus
High-dose – contains more viral antigens; recommended in patients 65 years of age and older
Adjuvanted Vaccine – contains an oil-in-water emulsion of squalene oil (MF59) that helps create a stronger immune response to vaccination; recommended in patients 65 years of age and older
Cell-based – prepared in cultured cells instead of hens’ eggs for patients with egg allergies.
So Can The Flu Vaccine Give You The Flu?
A typical fear expressed by many patients is that they will get the flu or get very sick from the vaccine. It is not uncommon that someone may experience a low-grade fever, body aches, headache, and an overall feeling of illness from the flu shot but this should not be mistaken for the flu (3). Once the inactivated or attenuated virus is injected into the body, the body will react to the foreign substance and initiate an immune response. This response by our body can be indicative that it is building immunity against the injected inactive or attenuated virus. Even though these symptoms can overlap with flu symptoms, they are not the flu itself. These autoimmune response symptoms are much less severe than what is experienced when one has the flu and they will typically resolve after two days. Because of the nature of the vaccine itself, this inactive or attenuated virus cannot be transmitted to others even if experiencing mild symptoms. Your pharmacist can provide helpful information on adequate remedies that could help alleviate these symptoms.
Antibodies are key functional units in our immune system that help us fight infections, including the flu. Our bodies may need up to two weeks after vaccination to build a sufficient quantity of antibodies that will protect us against the different strains of the flu. This means that patients that just received the flu vaccine are still vulnerable to infection for up to two weeks until our body can produce abundant antibodies. Flu vaccines do not cover all existing strains of the flu which means that we can still get infected by different strains that were not included in the administered vaccine.
For more information regarding vaccine-related concerns, you can reach out to your local pharmacists. If you’re local to Grass Lake, Grass Lake Community Pharmacy can be reached at (517) 522-4100.
Author: Raul Ghib | PharmD Candidate 2021 | University of Michigan
References
Seasonal Influenza Vaccine Dosage & Administration. (2017, January 05). Retrieved October 27, 2020, from https://www.cdc.gov/flu/about/qa/vaxadmin.htm
Different Types of Flu Vaccines. (2020, August 17). Retrieved October 27, 2020, from https://www.cdc.gov/flu/prevent/different-flu-vaccines.htm
Charlesworth, C. J., Smit, E., Lee, D. S., Alramadhan, F., & Odden, M. C. (2015). Polypharmacy Among Adults Aged 65 Years and Older in the United States: 1988–2010. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 70(8), 989-995. doi:10.1093/gerona/glv013