The purpose of this study is to evaluate the impact of LUS on the diagnosis and management of childhood pneumonia in developing countries

Inclusion Criteria (chest indrawing cases):

• Male or female, 2 through 23 months of age
• Cough <14 days or difficulty breathing
• Visible indrawing of the chest wall, with or without fast breathing
• Ability and willingness of child's caregiver to provide informed consent and to be available for follow-up for the planned duration of the study, including accepting a home visit if he/she fails to return to the study facility for a scheduled follow-up visit

Inclusion Criteria (non-chest indrawing controls):

• Male or female, 2 through 23 months of age
• Cough <14 days or difficulty breathing
• Ability and willingness of child's caregiver to provide informed consent and to be available for follow-up for the planned duration of the study, including accepting a home visit if he/she fails to return to the study facility for a scheduled follow-up visit

Cases will be children 2 through 23 months of age who present to a study hospital with history of cough or difficulty breathing and chest indrawing. Controls will be children 2 through 23 months of age who present with cough or difficulty breathing, but without chest indrawing, fast breathing or fever.

There is no plan to make individual participant data (IPD) available to other researchers.