Cmax is the maximum observed plasma analyte concentration.

AUC (0-last) is area under the plasma analyte concentration-time curve (AUC) from time 0 to time of the last quantifiable (non-below quantification limit \[non-BQL\]) concentration, calculated by linear-linear trapezoidal summation.

AUC (0-infinity) is the area under the plasma analyte concentration-time curve (AUC) from time zero to infinite time, calculated as the sum of AUC (0-last) and C(last)/lambda(z); wherein AUC (0-last) is area under the plasma concentration-time curve from time zero to last measurable concentration, C(last) is the last observed measurable (non-BQL) analyte concentration; and lambda(z) is apparent terminal elimination rate constant.

Cmax is defined as maximum observed plasma analyte.

AUC (0-last) is defined as the area under the plasma analyte concentration- time curve (AUC) from time 0 to the time of the last measurable (non-below qualification limit) concentration.

AUC (0-infinity) is defined as AUC from time 0 to infinite time, calculated as the sum of AUC(0-last) and C(last)/ lambda(z), wherein C(last) is the last observed quantifiable concentration; extrapolations of more than 20 percent (%) of the total AUC.

Plasma concentration of JNJ-64417184 under fasted and fed (low-fat meal, Ensure Original, standard meal, and high-fat meal as a reference) conditions will be determined.

An AE is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship.

Number of participants with laboratory abnormalities will be reported.

Number of participants with clinically significant changes in vital signs will be reported.

Number of participants with clinically significant changes in physical examination findings will be reported.

Number of participants with electrocardiogram (ECG) abnormalities will be reported.

The QT interval corrected for heart rate (QTc interval) using Fridericia method will be measured by electrocardiograms (ECG) triplicates.

FEV1 is the amount of air that can be exhaled in one second. FEV1 will be measured by spirometry. A positive change from baseline in absolute FEV1 indicates improvement in lung function.

FVC is a standard pulmonary function test used to quantify respiratory muscle weakness. FVC is the volume of air that can forcibly be blown out after full inspiration in the upright position, in liters and will be measured by spirometry.

FEV1 is the amount of air, measured in liters, forcibly exhaled in 1 second. Pulmonary function tests will be performed by participants in the morning before dosing. The percent predicted FEV1 equals the participant's observed FEV1 divided by the participant's predicted FEV1 (determined by height and race) and converted to a percentage by multiplying by 100 percent (%).

Predicted FVC is based on a formula using sex, age and height of a person, and is an estimate of healthy lung capacity. Percent of predicted FVC = (observed value)/(predicted value) \* 100 %.

Area under the concentration-time curve between time of first administration and Dosing Day 7 (AUC\[0-Dosing Day 7)\] of respiratory syncytial virus (RSV)-A Memphis 37b viral load in participants infected through inoculation with this viral strain, as determined by a quantitative real-time polymerase chain reaction (qRT PCR) assay of nasal wash (Part 4) will be assessed.