No one volunteers for a bout of influenza, but leeriness of possible vaccine-caused problems keep some of us at risk for this nasty bug. The Centers for Disease Control and Prevention estimates U.S. deaths from the influenza virus have ranged annually from 3,000 to 49,000 over the past few decades, despite the availability of influenza vaccine. A look at the known risks can help you decide if influenza vaccination is a good idea for you.
Flu Vaccination Side Effects
Reports of serious problems from flu vaccine are rare, according to the CDC. The most commonly reported side effect is soreness at the injection site. Flu vaccination can cause reactions in people who are allergic to components of the vaccine. Anyone experiencing signs or symptoms of a serious allergic reaction after receiving a flu vaccination should seek immediate emergency medical care. Such symptoms can include wheezing, trouble breathing, hives or swelling of the tongue, lips or throat. The rare neurological condition called Guillain-Barré syndrome has been linked to flu vaccination. Research is ongoing, but the risk of serious influenza complications far outweigh the likelihood of developing Guillain-Barré syndrome.
Other Flu-like Culprits
Currently, flu vaccine is given in 2 forms -- by injection and through a nasal spray. Killed virus is used to make the injectable vaccine and so cannot cause influenza in recipients. The nasal spray vaccine, LAIV or “live attenuated influenza vaccine,” originates from a live virus. However, the virus has been weakened so that, in healthy individuals, it typically provokes the creation of protective antibodies but not disease. Fever, fatigue and muscle aches can occur following injectable flu vaccine. Nasal spray flu vaccine can cause a runny nose and sore throat. Flu vaccine spurs our body to produce antibodies against only the specific influenza strains selected for each year's vaccine. It does not protect against other flu viruses, noninfluenza viral illnesses, bacterial infections or allergies. Flu season coincides with increases in other respiratory illnesses, many with symptoms similar to influenza. This can explain how some folks experience symptoms similar to the flu even though they have been vaccinated.
Limits of Protection
Two weeks is the approximate time it takes for a flu vaccination to become fully effective. People exposed to the flu right before or soon after vaccination are not fully protected yet and may indeed become ill with influenza. With age, our immune system becomes less robust. People over 65 years of age may not respond as effectively to vaccination as younger people do. These older people may become ill with the flu even though they're vaccinated. But they are less likely to require hospitalization for flu-associated problems and less likely to die of influenza than people their age who are unvaccinated.
Good for Most
Influenza vaccination is recommended by the CDC for any adult who would like to be protected against the flu. Injectable flu vaccine is suitable for adults of any age. LAIV is approved for healthy adults under age 50. LAIV is not recommended for pregnant women, people who have certain chronic diseases such as asthma or people who are immune-compromised or who have been diagnosed with Guillain-Barré syndrome. Neither vaccine should be given to someone who's allergic to any of the components. Your health-care provider can help with vaccine safety questions and recommend the best flu protection for you. Most of us can take advantage of flu vaccination and reap the benefits offered by this quick, relatively inexpensive protection.
- Centers for Disease Control and Prevention: Prevention and Control of Seasonal Influenza With Vaccines -- Recommendations of the Advisory Committee on Immunization Practices -- United States, 2013–2014
- New England Journal of Medicine: The Safety of Inactivated Influenza Vaccine in Adults and Children With Asthma
- PLoS ONE: Guillain-Barré Syndrome, Influenza Vaccination, and Antecedent Respiratory and Gastrointestinal Infections -- A Case-Centered Analysis in the Vaccine Safety Datalink, 2009–2011
- Centers for Disease Control and Prevention: 2013-2014 Seasonal Influenza Vaccine Safety
- Centers for Disease Control and Prevention: Live Attenuated Influenza Vaccine [LAIV] (The Nasal Spray Flu Vaccine)
- Centers for Disease Control and Prevention: Vaccine Effectiveness -- How Well Does the Flu Vaccine Work?
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