The Centers for Disease Control and Prevention strongly recommends vaccination against influenza in children under five due to the higher risk of severe illness and complications in this group. For example, during the 2009-2010 flu season, the Food and Drug Administration (FDA) approved two vaccines, Afluria and Fluzone, for use in toddlers. However, the flu shot is commonly associated with after effects that parents and caregivers may wish to consider in scheduling their child for vaccination. The after effects of these two vaccines are typical in toddlers.
Injection Site Pain
In the clinical studies described in the product literature for Afluria, injection site pain was one of the most common after effects of the flu shot in toddlers. In children six months to three years old, localized pain, redness and swelling was observed up to five days after injection in 37, 38, and 21 percent, respectively. In 99 percent of cases, symptoms were rated by parents as mild or moderate. Redness and swelling are easy to identify. Parents and caregivers of children who are not yet speaking should watch for other signs of pain such as fussiness, irritability, crying and favoring the opposite extremity.
Flu-Like Illness
Flu-like illness is a common after effect of the flu shot in both adults and children. In contrast to true influenza infection, symptoms are characteristically mild and brief (one to two days). In the in-house clinical trial data described in Afluria's product literature, the most frequent symptoms in children under three were: runny nose (48 percent), irritability (48 percent), cough (32 percent), loss of appetite (24 percent), fever--defined as oral temperature greater than 101.3 degrees F or underarm temperature greater than 99.4 degrees--(23 percent), vomiting or diarrhea (15 percent), generalized muscle pain (9 percent), sore throat (5 percent), headache (3 percent), muscle pain (3 percent) and ear ache (3 percent.) Severe fever, defined as oral temperature greater than 104 degrees F or underarm temperature greater than 103.1 degrees F, was observed in less than 1 percent of children. Similar results were reported for Fluzone in its company literature.
Allergic Reactions
Allergic reactions are an uncommon side effect of the flu vaccine. Allergic reactions reported in children who received Fluzone include hives, wheezing, angioedema (swelling under the skin) and anaphylaxis. Anaphylaxis, in particular, is a severe, potentially fatal allergic reaction that requires immediate medical attention. Symptoms of anaphylaxis, according to the American College of Allergy, Asthma and Immunology, include trouble breathing, hives or swelling, tightness of the throat, hoarse voice, vomiting, abdominal pain, diarrhea, low blood pressure and rapid heartbeat which may progress rapidly to cardiac arrest and death. Anaphylaxis usually occurs after repeated exposure to an allergen. Since toddlers receive two flu shots on separate occasions, anaphylaxis is may be more common after the second injection. Toddlers with a history of hypersensitivity to eggs, certain kinds of antibiotics, previous flu shots or other kinds of vaccine are more likely to have a reaction to the flu shot.
Acute Disseminated Encephalomyelitis
Acute Disseminated Encephalomyelitis (ADE) is a rare, but serious side effect of the flu shot and other kinds of vaccines including diptheria, polio and rabies, among others. ADE is most common in children, according to a 2008 study in the Journal of Clinical Neuroscience, and typically presents with sudden, simultaneous of several symptoms including fever, muscle weakness, abnormal reflexes, vision loss or changes, impaired balance, forgetting previously known words and other symptoms within three months after receiving the vaccine. Fever resolves sooner than neurological deficits, which may last months or years. ADE is extremely rare and is probably involves patient-specific risk factors, although these have not yet been identified.
References
- CDC: Seasonal and 2009 H1N1 Flu -- A Guide for Parents
- FDA: Influenza Virus Vaccine for the 2009-2010 Season
- Journal of Clinical Neuroscience; Post-Vaccination Encephalomyelitis: Literature Review and Illustrative Case; W. Huynh, D.J. Cordato, E. Kehdi, L.T. Masters and C. Dedousis; 2008
