An estimated average of 6514 infants aged younger than 12 months were hospitalized for influenza infection each year between 2003 and 2012, according to an analysis of population-based influenza hospitalization surveillance data collected by the Centers for Disease Control and Prevention.
An average of 6514 infants aged younger than 1 year were hospitalized for influenza infection each year between 2003 and 2012, according to population-based influenza hospitalization surveillance data collected by the Centers for Disease Control and Prevention. About 50% of these hospitalizations were in infants aged younger than 3 months, followed by those aged 6 months to younger than 12 months (32%) and infants aged 3 months to younger than 6 months (18%).
Although the overall number of hospitalizations varied from one season to another (ranging from a low of 1842 during the 2011-2012 season to a high of 12,502 during the 2003-2004 season), the rates always were highest among those aged younger than 3 months, about 3-fold higher than those in older infants.
Most hospitalizations (75%) were in infants who did not have any identified high-risk conditions for influenza complications, such as lung, cardiovascular, renal, or metabolic disease; neurologic or neuromuscular disorder (NNMD); an immunocompromised condition; or prematurity. The prevalence of such high-risk conditions (prematurity was the most common followed by lung disease, cardiovascular disease, and NNMD) increased with age, from 15% among infants aged younger than 3 months to 38% among those aged 6 months to younger than 12 months.
Infants who did have high-risk conditions were 2 to 3 times more likely than other infants hospitalized for influenza infection to be admitted to the intensive care unit (ICU) or experience respiratory failure. Nonetheless, even among otherwise healthy admitted infants, up to 10% were admitted to the ICU and up to 4% had respiratory failure (Chaves SS, et al. Pediatr Infect Dis J. 2014;33:912-919).
Ms Freedman is a freelance medical editor and writer in New Jersey. Dr Burke, section editor for Journal Club, is chairman of the Department of Pediatrics at Saint Agnes Hospital, Baltimore, Maryland. The editors have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.