Flu Mist is a live intranasal seasonal influenza vaccine which is FDA-approved for healthy people between the ages of two and 49. The makers of Flu Mist, MedImmune LLC, also produced a live intranasal pandemic H1N1 influenza vaccine for the 2009-2010 season, although this is not marketed as Flu Mist. Flu Mist produces "active" immunity against the influenza virus by causing an infection with a weakened version of the virus; however, this is not without some danger.
Common Side Effects
According to the manufacturer's product information, approximately ten percent of patients who receive Flu Mist complain of runny nose, nasal congestion and/or sore throat. In children between two and six, fever greater than 100 degrees F is observed in approximately ten percent. Most symptoms are mild and resolve within one or two days. People with asthma or children with a history of wheezing should not be vaccinated with Flu Mist because Flu Mist can provoke these symptoms.
Influenza Infection
According to the manufacturer, Flu Mist is a live, albeit weakened, version of the influenza virus which produces immunity by actually causing an infection. In healthy people, the vaccine rarely produces symptoms. However, the safety of Flu Mist in children younger than two, people with compromised immune systems, people 50 and older and people considered at high risk for influenza complications has not been assessed and these people should not use Flu Mist.
Guillain-Barre Syndrome
Guillain-Barre syndrome (GBS) is an autoimmune disorder in which the body manufactures antibodies against sites on the peripheral nerves. According to the National Institute of Neurological Disorders and Stroke, initial symptoms of GBS include muscle weakness and tingling that begins in the legs and progressively moves up the body. In severe cases, a person may be completely paralyzed and require a ventilator to breathe, due to paralysis of the diaphragm. In 90 percent of patients, symptoms peak at approximately three weeks. Between five percent and six percent of people with GBS die. Among those who survive, recovery is prolonged; 30 percent of patients still report residual weakness three years after infection. GBS is usually related to bacterial infection with Campylobacter jejuni. However, one in 1 million people who received a swine flu vaccine in 1976 and seasonal flu vaccine between 1992 and 1994 also developed the disease. No cases have been associated with Flu Mist, however the FDA requires all manufacturers of influenza vaccine to note this risk in product literature.
Reye's Syndrome
According to the National Institutes of Health, Reye's Syndrome has been described in children and teenagers with influenza who have been treated with aspirin or aspirin-containing products. Initial symptoms of Reye's Syndrome include nausea, vomiting, agitation, irritability, confusion, combativeness and hyperactivity. The syndrome deteriorates rapidly to seizures and coma, which may be irreversible. Since Flu Mist induces immunity through infection with live influenza virus, children and teenagers who have been vaccinated with Flu Mist should not receive aspirin or aspirin-containing products. Acetaminophen appears to be safe.
