ATLANTA — Children and adults with neurologic and neuromuscular conditions that place them at increased risk for influenza complications will be added to the list of individuals who should be targeted to receive the vaccine, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices decided at its winter meeting.
The final wording of the 2005-2006 influenza immunization statement is still being finalized, but in general, any neurologic and neuromuscular condition that increases the risk for respiratory compromise or aspiration would place patients at even greater risk if they were to contract influenza, said Carolyn Bridges, M.D., of the CDC's National Immunization Program.
The list of individual conditions is long, but it broadly includes seizure disorders, mental retardation, cerebral palsy, Down syndrome, muscular dystrophy, and other developmental problems with limitation. Among adults, stroke, multiple sclerosis, Parkinson's disease, and senility/dementia/Alzheimer's disease with limitation also are likely to be included.
Depending on which conditions are included in the final statement, the number of children and adults who may be added to the target list for influenza vaccination would be approximately 524,000-907,000 children aged 2-17 years, 529,000-1.7 million adults aged 18-49, and 571,000-844,000 individuals aged 50-64, Dr. Bridges said.
Among the data supporting the recommendation are preliminary findings from two studies in which such conditions were prevalent among children with severe influenza.
Of 153 fatal influenza cases reported during the 2003-2004 season in persons younger than 18 years (range 2 weeks to 17 years), 45% were previously healthy, 20% had conditions that ACIP had previously designated as high risk, while 20% had conditions such as congenital anomalies, gastrointestinal disorders, and neurologic/neuromuscular conditions. Another 20% had both neurologic/neuromuscular conditions and a previously designated high-risk condition. (No data were available for the other 3%.)
The neurologic conditions in those children were mental retardation/developmental delay, seizure disorder (excluding febrile), chronic encephalopathies, neurodegenerative disorders, and congenital neurologic disorders. The neuromuscular conditions were cerebral palsy and Duchenne's muscular dystrophy. Some children had more than one of the diagnoses.
A 4-year retrospective study of 757 children hospitalized with community-acquired, laboratory-confirmed influenza was conducted at Children's Hospital of Philadelphia, where diagnostic testing is routinely done for most children admitted with respiratory symptoms. Previously designated high-risk conditions were present in 44% of the children, the most common being asthma, in 24%, Dr. Bridges reported.
Among the 425 who did not have one of the previously listed conditions, neurologic/neuromuscular conditions were present in 22%. These included disease of the central or peripheral nervous system, seizure disorders, or myopathies. In a subanalysis of 33 children with respiratory failure, having a neurologic or neuromuscular condition increased the risk nearly sevenfold.