a two-part infant study for early diagnosis of respiratory syncytial virus (rsv) and evaluation of jnj-53718678 in rsv acute respiratory tract disease

Conditions: Respiratory Syncytial Viruses

Summary: the purpose of this two-part designed study is to assess in the setting of a planned early interception of pediatric rsv disease, early viral and disease kinetics (observational stage) and the antiviral effects of an respiratory syncytial virus (rsv) fusion inhibitor, jnj-53718678 (interventional stage). in the observational stage the infant is closely monitored for early symptoms by the parent(s)/caregiver(s) and thus may be brought in for diagnosis earlier than in the typical setting.


Eligibility criteria:
inclusion criteria: part 1: observational stage * the infant is less than or equal to (\<=) 4 months of age at enrollment and asymptomatic for acute respiratory illness (ari)-like symptoms requiring medical intervention at the time of consent to participate in the study * at least 1 parent/caregiver must be able to use the respiratory syncytial virus (rsv) mobile application (app) at home via his/her own android/ios electronic device (compatible with rsv mobile app) * the participant must have been assessed per local public health practice and considered not to have severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection part 2: interventional stage * the infant is 28 days and if prematurely born infant (that is \[i.e.\], less than \[\<\] 37 weeks and 0 days of gestation at birth) is at least 3 months postnatal age * the participant has been diagnosed with rsv infection using a rapid molecular-based diagnostic assay * the participant weighs more than 2.4 kilogram (kg) * the participant has an acute respiratory illness as evaluated by the investigator * except for the rsv-related illness, the participant must be medically stable in case of allowed co-morbid conditions * the participant must have been assessed per local public health practice and considered not to have sars-cov-2 infection during this respiratory infection exclusion criteria: part 1: observational stage * the participant has any physical abnormality which limits the ability to collect regular nasal specimens * the participant is receiving chronic home oxygen therapy at enrollment (applicable to both parts) part 2: interventional stage * the participant is \<3 months postnatal age at screening and was born prematurely (i.e., \<37 weeks and 0 days of gestation) or if the participant weights \<2.4 kg * the participant has a qt interval with fridericia's correction (qtcf) greater than (\>) 450 milliseconds per the machine read (mean of triplicate) parameter result confirmed by repeat triplicate electrocardiogram (ecg) recording during screening * the participant is considered by the investigator to be immunocompromised, whether due to underlying medical condition or medical therapy * the participant has had any of: a) confirmed sars-cov-2 infection (test positive) during the four weeks prior to randomization, or b) close contact with a person with coronavirus disease 2019 (covid-19) (test confirmed or suspected sars-cov-2 infection) within 14 days prior to randomization