The goal of this clinical trial is to determine if a "watch and wait" antibiotic strategy, called Safety Net Antibiotic Prescribing (SNAP), can safely reduce unnecessary antibiotic use while ensuring that children diagnosed with community-acquired pneumonia get better from their illness. The main aims of this study are:

• To compare the effectiveness of SNAP versus immediate antibiotic prescribing in children with mild community-acquired pneumonia (CAP)
• To identify which patient groups benefit most from the SNAP strategy
• To identify factors that shape implementation of each prescribing strategy.

Researchers will compare the SNAP strategy (where parents or guardians are instructed to give antibiotics only if their child is not improving after 72 hours, or sooner if they are worsening) to the immediate antibiotic prescribing strategy (where parents or guardians are instructed to give the antibiotics right after their healthcare visit) to see if one strategy is more effective than the other.

Participants will be randomly assigned to either the immediate antibiotic group or the SNAP group at enrollment. Participation lasts 14 days with follow-up surveys at 4, 7, and 14 days after enrollment.

This study is a multicenter, Hybrid Type-1effectiveness-implementation randomized clinical trial (RCT) designed to evaluate the effectiveness of a "Safety Net Antibiotic Prescribing" (SNAP) strategy versus an immediate antibiotic prescribing strategy for young children 12 months to <6 years of age with community-acquired pneumonia (CAP) who are treated as outpatients.

This study will recruit eligible patients from approximately 19 clinical sites consisting of pediatric emergency departments (EDs), primary care offices, and urgent care centers within the United States and enroll up to 2,000 patients. Patient recruitment will occur over a 3.5-year period. Participants will be identified and screened during routine visits at the clinical sites.

Through an online system, participants will be randomized to either the immediate antibiotic group or the SNAP group. All participants will receive a prescription for antibiotics as per usual care from their treating clinician.

The parents or guardians of the participants will be asked to complete an online survey on Days 4 and 14 (+/- 2 days) to collect data for the secondary outcomes, including quality of life, satisfaction, and return visits. On Day 7 (+/- 2 days), the parents or guardians of the participants will be contacted by phone to collect data for the primary outcome, focusing on clinical improvement and antibiotic use.

Acceptability and feasibility will be assessed with parent or guardian and clinician surveys and interviews. Parents or guardians will be surveyed at Day 14 and a subset will be invited for interviews within a month of the final follow-up visit. Clinicians will be surveyed, and a subset will be interviewed at the conclusion of the trial.

Inclusion Criteria:

• Aims 1 and 2:
• Presenting with signs and symptoms of lower respiratory tract infection
• Diagnosed with community-acquired pneumonia (CAP) by a clinician
• The treating clinician intends to prescribe antibiotics for CAP, AND
• Well enough, as determined by the clinician at the time of the study enrollment visit, to be managed as an outpatient.
• Aim 3:
• Parent/guardian of child enrolled in the trial, OR
• Clinician who makes prescribing decision at the study site, OR
• Other practice-based parties (e.g. nurses, pharmacists, medical assistants, practice leaders) at study sites who can comment on the implementation of each prescribing strategy.

Exclusion Criteria:

• Aims 1 and 2:
• Hospitalization within the previous 7 days
• Oxygen saturation below 90%, if measured
• Incomplete immunization status (e.g., lacking at least 3 doses of the pneumococcal vaccines, typically given as part of the 2-, 4-, and 6-month vaccinations)
• Chronic medical conditions that increase the risk of bacterial CAP (e.g., chronic lung disease, cystic fibrosis, sickle cell disease),
• Substantially immunocompromised status (e.g., immunodeficiency, active cancer treatment, organ transplant with concurrent immunosuppressive agents)
• Receipt of oral or parenteral antibiotics within the previous 7 days
• Diagnosis of complicated pneumonia (e.g., empyema, lung abscess)
• Known bacterial source of infection warranting immediate antibiotics
• Pneumonia diagnosis within the previous 6 months, OR
• Prior enrollment in the trial
• Inability of the parent or guardian to speak English or Spanish
• Aim 3:
• Inability of the parent or guardian to speak English

At the conclusion of the study, a de-identified dataset will be prepared and made available for sharing with investigators as specified by the lead investigators and the funding agency. Data sharing will follow established guidelines to ensure that any shared dataset does not contain protected health information (PHI) and is fully anonymized. Investigators requesting access to the dataset will need to submit a data use agreement, specifying how the data will be used. Results of the study will be disseminated through peer-reviewed journals, presentations at scientific meetings, and the PCORI website.

Aim 3 interview transcripts will not be shared to a publicly available repository since it will be impossible to fully anonymize the transcripts.