Table 1 Study outcome definitions

Clinical Upper Respiratory Tract Infection (URTI)

A new-onset illness consisting of at least two of the following clinical criteria at any time during a surveillance week:

• Caregiver-reported cough;

• Caregiver-reported rhinorrhea;

• Caregiver-reported nasal congestion;

• Measured temperature ≥37.5 °C (axillary)

confirmed with 2nd measurement

Clinical Lower Respiratory Tract Infection (LRTI)

• Caregiver-reported cough AND/OR difficulty breathing during a surveillance week

AND

• Observed elevated respiratory rate (60 breaths per minute or greater for infant up to 59 days of age, or 50 breaths per minute or greater for infant 60 days of age or older) and/or lower chest wall in-drawing

OR

• Hospitalization with physician diagnosis of pneumonia or bronchiolitis

Microbiologically Confirmed URTI

URTI that tests positive for at least one of influenza A, influenza B, respiratory syncytial virus, parainfluenza 1, 2, and 3, adenovirus, or human metapneumovirus

Microbiologically Confirmed LRTI

LRTI that tests positive for at least one of influenza A, influenza B, respiratory syncytial virus, parainfluenza 1, 2, and 3, adenovirus, or human metapneumovirus