This secondary analysis of a vaccine efficacy trial evaluates the duration of infant protection against influenza conferred by maternal immunization.
To determine the impact of influenza coinfection on outcomes for children with complicated pneumonia.
Retrospective cohort study.
Forty children's hospitals that contribute data to the Pediatric Health Information System.
Children discharged from participating hospitals between January 1, 2004, and June 30, 2009, with complicated pneumonia requiring a pleural drainage procedure.
Intensive care unit admission, receipt of mechanical ventilation, receipt of vasoactive infusions, receipt of blood product transfusions, in-hospital death, readmission within 14 days of hospital discharge, hospital length of stay, and cost of hospitalization.
Overall, 3382 of 9680 children with complicated pneumonia underwent pleural fluid drainage; 105 patients (3.1%) undergoing pleural drainage had influenza coinfection. A bacterial pathogen was identified in 1201 cases (35.5%); the most commonly identified bacteria were Staphylococcus aureus in children with influenza coinfection (22.9% of cases) and Streptococcus pneumoniae in children without coinfection (20.0% of cases). In multivariable analysis, influenza coinfection was associated with higher odds of intensive care unit admission and receipt of mechanical ventilation, vasoactive infusions, and blood product transfusions as well as higher costs and a longer hospital stay. Children with influenza coinfection were less likely to require readmission, although there was a trend toward higher odds of mortality for patients with coinfection. In a subanalysis stratified by bacteria, outcomes remained worse for coinfected children in the subgroups of children with S aureus and with no specified bacteria.
Influenza coinfection occurred in 3.1% of children with complicated pneumonia. Clinical outcomes for children with complicated pneumonia and influenza coinfection were more severe than for children without documented influenza coinfection.
To assess the effect of seasonal influenza vaccination during pregnancy on laboratory-confirmed influenza in infants to 6 months of age.
Nonrandomized, prospective, observational cohort study.
Navajo and White Mountain Apache Indian reservations, including 6 hospitals on the Navajo reservation and 1 on the White Mountain Apache reservation.
A total of 1169 mother-infant pairs with mothers who delivered an infant during 1 of 3 influenza seasons.
Maternal seasonal influenza vaccination.
In infants, laboratory-confirmed influenza, influenzalike illness (ILI), ILI hospitalization, and influenza hemagglutinin inhibition antibody titers.
A total of 1160 mother-infant pairs had serum collected and were included in the analysis. Among infants, 193 (17%) had an ILI hospitalization, 412 (36%) had only an ILI outpatient visit, and 555 (48%) had no ILI episodes. The ILI incidence rate was 7.2 and 6.7 per 1000 person-days for infants born to unvaccinated and vaccinated women, respectively. There was a 41% reduction in the risk of laboratory-confirmed influenza virus infection (relative risk, 0.59; 95% confidence interval, 0.37-0.93) and a 39% reduction in the risk of ILI hospitalization (relative risk, 0.61; 95% confidence interval, 0.45-0.84) for infants born to influenza-vaccinated women compared with infants born to unvaccinated mothers. Infants born to influenza-vaccinated women had significantly higher hemagglutinin inhibition antibody titers at birth and at 2 to 3 months of age than infants of unvaccinated mothers for all 8 influenza virus strains investigated.
Maternal influenza vaccination was significantly associated with reduced risk of influenza virus infection and hospitalization for an ILI up to 6 months of age and increased influenza antibody titers in infants through 2 to 3 months of age.
To evaluate the effect of adverse events associated with live attenuated influenza vaccine (LAIV) in children younger than 5 years on the cost-effectiveness of influenza vaccination.
A decision analytic model was developed to predict costs and health effects of no vaccination, vaccination with LAIV, and vaccination with inactivated influenza vaccine (IIV). Probabilities, costs, and quality adjustments for uncomplicated influenza, outpatient visits, hospitalizations, deaths, vaccination, and vaccine adverse events were based on primary and published data. The analysis included the possible increased incidence of adverse events following vaccination with LAIV for children younger than 5 years, including fever, wheezing, and hospitalization. A societal perspective was used. Sensitivity analyses, including probabilistic sensitivity analysis, were conducted.
Vaccination in the physician office setting in the United States.
Hypothetical cohorts of healthy children aged 6 months to 4 years.
Vaccination with LAIV or IIV.
Incremental cost-effectiveness ratio in dollars per quality-adjusted life-year (QALY).
Cost-effectiveness ratios ranged from $20 000/QALY (age 6-23 months) to $33 000/QALY (age 3-4 years) for LAIV and from $21 000/QALY to $37 000/QALY for IIV for healthy children aged 6 months to 4 years. Inclusion of possible new adverse events for LAIV had varying effects on cost-effectiveness results. Results were not sensitive to the inclusion of wheezing as an adverse event but were sensitive to a possible increase in the probability of hospitalization.
Live attenuated influenza vaccine had comparable cost-effectiveness compared with IIV for children younger than 5 years under a wide range of assumptions about the incidence of adverse events.