Flu Vaccine May Be Linked with Asthma in Infants

A study of more than 9,000 children and adolescents indicates that the use of the nasal influenza vaccine (FluMist) is generally safe. However, questions still remain about the risk of reactive airway disease in certain children under the age of 3 years.

A study of more than 9,000 children and adolescents indicates that the use of the nasal influenza vaccine (FluMist) is generally safe. However, questions still remain about the risk of reactive airway disease in certain children under the age of 3 years. As researcher Dr. Steve Black told Reuters Health, “there was a suggestion that (such) children vaccinated with (FluMist) were at increased risk for medical visits for asthma within 6 weeks following vaccine as compared to controls. However, children with asthma prior to vaccination, overall, had a lower risk of asthma visits as compared to controls.” In the Pediatric Infectious Disease Journal, Black of the Kaiser Permanente Vaccine Study Center in Oakland, California, and colleagues note that they came to these conclusions after a trial of the nasal flu vaccine in children between 1 and 17 years old. All received at least one dose of vaccine or placebo. Those 8 years or younger received a second dose 28 to 42 days later. All children were followed for 42 days after each vaccination. Following evaluation of 9,689 children, there appeared to be no association between vaccination and acute respiratory tract infections, systemic bacterial infection, acute GI complaints, and those potentially associated with influenza. However, in children aged 18 to 35 months there was a four-fold increased risk of reactive airway disease. Thus, continued Dr. Black, “our conclusion was that the risk of asthma following (nasal flu vaccination) in children less than three years old needed further evaluation prior to the use of the vaccine in that age group.” They theorize that if this increased risk is confirmed in another study, it may be that these children have never been exposed to an influenza virus “and might respond to this vaccine differently because of this.” (Source: Pediatric Infectious Disease Journal, Reuters Health, March 2004)