A Study to Evaluate a Single Intravenous Dose of Motavizumab for the Treatment of Children Hospitalized With Respiratory Syncytial Virus (RSV) Illness

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children less than or equal to (<=12) months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

The RSV viral load is measured by cultivatable virus and real-time RT-PCR in the upper respiratory tract in previously healthy children <=12 months of age who are hospitalized with lower respiratory tract illness.

Motavizumab concentration in nasal wash aspirates is reported.

Motavizumab concentration in nasal wash aspirates is reported.

Motavizumab concentration in nasal wash aspirates is reported.

Motavizumab concentration in nasal wash aspirates is reported.

Motavizumab concentration in nasal wash aspirates is reported.

Duration of RSV hospitalization is reported.

The RACS assesses changes in wheezing and retractions as measured by respiratory distress assessment instrument (RDAI) score and changes in respiratory rate. A RDAI score is a measure of the degree of severity of wheezing and retractions, with score range from 0 to 17; higher scores indicate more severe disease. Respiratory rate is summarized by raw scores and standardized change score. A change in respiratory rate of less than or equal to (<=) 5% from baseline is counted as a change of 0 units and a change in respiratory rate is assigned 1 point per each 10% change in the respiratory rate. The RACS is calculated as arithmetic sum of RDAI score change and of standardized respiratory rate change (for example, a child showing improvement who had a RDAI of -5 and a respiratory rate change of -2 would have a RACS score of -7). The RACS assessment does not have a minimum and/or maximum scale range. A decrease in RACS represents improvement, whereas an increase signifies deterioration.

Oxygen saturation level during RSV hospitalization is reported.

Heart rate during RSV hospitalization is reported.

Respiratory rate during RSV hospitalization is reported.

Number of participants with supplemental oxygen use during RSV hospitalization is reported.

Duration of supplemental oxygen use during RSV hospitalization is reported.

Number of participants on mechanical ventilation during RSV hospitalization is reported.

Duration of mechanical ventilation during RSV hospitalization is reported.

Number of participants admitted to ICU is reported.

Duration of ICU stay during RSV hospitalization is reported.

Wheezing episodes are considered medically-attended wheezing episodes if the medical care provider verifies and documents wheezing in the medical record or, in the case of hospitalization, the medical care provider assigns a discharge diagnosis of asthma, bronchiolitis, wheezing, or reactive airway disease. A new wheezing episode is the one that occurs for more than 2 weeks after the diagnosis of the previous episode and the medical opinion is that the wheezing does not represent a persistence of the previous episode. Medically-attended wheezing episodes were calculated and reported in the range of 0 to 9 events.

Motavizumab concentration in serum is reported.

Number of participants with detectable anti-motavizumab antibodies are reported. Detection is defined as an anti-motavizumab antibody titer with a dilution value of 1:30 or greater.

Change from baseline in upper respiratory tract (nasal wash) cytokine levels are reported.

An adverse event (AE) is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. A serious adverse event (SAE) is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life threatening experience immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. The TEAEs are defined as events present at baseline that worsened in intensity after administration of study drug or events absent at baseline that emerged after administration of study drug.