A nationwide, multicenter, randomized, non-inferiority trial of children with bone and joint infections. The primary objective is to determine if oral-only antibiotics (experimental arm) is non-inferior to initial intravenous antibiotics followed by oral therapy (control arm). Children will be randomized 1:1. The total treatment duration is identical in both groups. The study is open label with blinding of the primary endpoint assessor.

Inclusion Criteria:

• Children aged 3 months to 18 years with antibiotic treatment of uncomplicated bone or joint infection.

Exclusion Criteria:

1. Severe disease, e.g. septic shock, or any concomitant infection, e.g. necrotizing fasciitis, requiring IV antibiotics in the opinion of the treating clinician.
2. Complicated bone or joint infection, e.g. prosthetic material, infection secondary to or complicated by trauma, severe pyomyositis or other substantial soft tissue infections.
3. Expected need of major surgery within the first 24 hours of treatment, e.g. drilling, debridement, fenestration, surgical drainage, synovectomy. Minor surgery as diagnostic surgical bone biopsy or diagnostic joint fluid aspiration including lavage is not a criterion for exclusion.
4. Significant co-morbidities that might influence the choice of treatment or the course of the infection, e.g. immunodeficiency, immunosuppressive therapy, sickle cell anemia.
5. Previous bone or joint infection.
6. Antibiotic therapy for more than 24 hours before inclusion.
7. Documented pathogen with limited treatment options that do not permit randomization, e.g. the pathogen is only sensitive to intravenous antibiotics.
8. Prior enrolment in the trial

Study protocol and statistical analysis plan will be shared. The exact plan for sharing Individual Participant Data (IPD) is being prepared.

The assessor (qualified pediatrician or pediatric surgeon) of the primary endpoint (sequelae 6 months after initiation of treatment) will be blinded for the intervention as well as any other details on the course of disease. The assessor will be informed about the age of the child as well as the approximate location of the infection and will perform a predefined systematic clinical examination of the relevant area (categories: 1) lower extremities, 2) upper extremities incl. claviculae and scapulae and 3) columna, costae and sternum). The exact anatomical location including side (left or right) will not be revealed. The child and parents will be followed by a study nurse who will secure that the blinding is respected. The primary endpoint is met if there are any positive findings related to the previously infected bone or joint.