Diagnosis of Mycoplasma Pneumoniae Infection With Detection of Specific Antibody-secreting Cells in Community-acquired Pneumonia (CAP) Patients of the Randomised Placebo-controlled Multi-centre Effectiveness Trial of Adjunct Betamethasone Therapy

Inclusion Criteria: * At least 12 months of age and younger than 10 years of age * Body weight between 7 kg and 35 kg * Admission to hospital (i.e. assignment of an inpatient case number) * Clinical diagnosis of CAP (according to predefined criteria) * Parent and/or child (as age-appropriate) willing to accept all possible randomised allocations and to be contacted by telephone weekly up to and including at 4 weeks after randomisation * Informed consent form for trial participation signed by parent Exclusion Criteria: * Presence of local chest complications * Chronic underlying disease associated with an increased risk of very severe CAP or CAP of unusual aetiology * Bilateral wheezing without focal chest signs (most likely to represent respiratory tract infection affecting the medium airways, i.e. not pneumonia) * Inability to tolerate oral medication * Documented allergy or any other known contraindication to any trial medication * Subacute or chronic conditions requiring higher betamethasone equivalent or known primary or secondary adrenal insufficiency * Known diabetes mellitus (type 1) * Hospitalisation within the last two weeks preceding current admission * Exposure to systemic corticosteroids with completion of treatment \<2 weeks from enrolment (courses of up to 7 days) or \<4 weeks from enrolment (courses of \>7 days) * Transfer for any reason to a non-participating hospital directly from the paediatric emergency department * Parent are unlikely to be able to reli…