To better understand acquired immunity to respiratory-syncytial-virus infections, we analyzed data from a 10-year study of respiratory illness in normal children who were followed longitudinally from early infancy. Immunity was measured in terms of failure to become infected or reduction in severity of clinical illness upon reinfection. Outbreaks of infections occurred seven times over the 10-year-period. During epidemics the attack rate for first infection was 98 per cent. The rate for second infections (75 per cent) was modestly reduced (P less than 0.001); that for third infections was 65 per cent. Age and history of infection both influenced illness. Immunity induced by a single infection had no demonstrable effect on illness associated with reinfection one year later; however, a considerable reduction in severity occurred with the third infection. These observations suggest that amelioration of illness--rather than prevention of infection--may be a realistic goal for immunoprophylaxis.

OBJECTIVE Inflammatory markers such as C-reactive protein (CRP) are related to obesity in adults, but the association is less clear in children. Our objective was to examine relationships between multiple markers of inflammation and children’s weight status; we hypothesized that the prevalence of inflammatory markers would increase as weight status increased. METHODS We conducted a cross-sectional analysis of children in the United States aged 1 to 17 years in the National Health and Nutrition Examination Survey, 1999–2006. Children were categorized using weight-for-length when age < 2 years and BMI for ≥2 years, as very obese (≥99th percentile), obese (< 99th and ≥95th percentile), overweight (< 95th and ≥85th percentile), and healthy weight (> 5th to ≤85 thpercentile)according to expert consensus. Our main outcome measures were high-sensitivity CRP and absolute neutrophil count, in addition to a novel third measure: ferritin controlled for iron status using a ferritin/transferrin ratio. We used Cox proportional hazards models to examine risk of abnormal values of inflammatory markers according to weight. RESULTS Increased risk of a CRP level of > 1.0 mg/L was evident among very obese children from ages 3 to 5 years (hazard ratio [HR]: 2.29; P < .01) through 15 to 17 years (HR: 4.73; P < .01). Increased risk of abnormal neutrophil count among very obese children began at 6 to 8 years (HR: 2.00; P = .049), and increased prevalence of abnormal ferritin/transferrin ratio began at 9 to 11 years (HR: 7.06; P < .001). CONCLUSIONS Multiple inflammatory markers are strongly and positively associated with increasing weight status in children, and this relationship starts as young as age 3. Elevated inflammatory markers in very young obese children are particularly concerning, because inflammation may cause long-term, cumulative vascular damage. This deserves additional research via longitudinal design.

Children in a day care center underwent serial nasal lavages in order to assess nasal cytokine expression during acute upper respiratory infections (URI). Interleukin (IL)-1 beta, IL-8, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were markedly elevated in nasal lavage fluid during acute URI compared to baseline, and all except TNF-alpha decreased significantly by 2-4 weeks later. Cytokine patterns in respiratory syncytial virus-positive and -negative illnesses did not differ significantly. A subgroup of children also underwent superficial mucosal biopsy under the inferior nasal turbinate. During acute URI, biopsy cells (90%-95% epithelial) showed increased transcripts for IL-1 beta, IL-8, and IL-6 in 7 of 9 subjects, suggesting that epithelial cells may be one source of cytokines during acute URI. The results show that inflammatory cytokines are elevated in nasal secretions during acute URI in preschool children. Thus, cytokines are likely to participate in regulation of respiratory virus-induced inflammation.

We analyzed data from a 14-year longitudinal study of respiratory infections in young children to determine the relative importance of viral respiratory infection and nasopharyngeal colonization with Streptococcus pneumoniae and Haemophilus influenzae as factors influencing the occurrence of acute otitis media with effusion. The incidence of this disorder was increased in children with viral respiratory infections (average relative risk, 3.2; P less than 0.0001). Infection with respiratory syncytial virus, influenza virus (type A or B), and adenovirus conferred a greater risk of otitis media than did infection with parainfluenza virus, enterovirus, or rhinovirus. Colonization of the nasopharynx with Str. pneumoniae or H. influenzae had a lesser effect on the incidence of the disease (average relative risk; 1.5; P less than 0.01). Infections with the viruses more closely associated with acute otitis media (respiratory syncytial virus, adenovirus, and influenza A or B) were correlated with an increased risk of recurrent disease. Prevention of selected otitis-associated viral infections should reduce the incidence of this disease.

Zanamivir was effective in shortening the duration and severity of influenza symptoms and was well-tolerated among children 5 to 12 years of age.