Bass 1969.

Methods	Randomised controlled trial
Participants	Inclusion criteria: hospitalised children with clinical pertussis and initial nasopharyngeal swap positive for B. pertussis both by culture and by fluorescent microscopy. Patients who had received previous antimicrobial therapy or those who had previous immunisation against pertussis were not excluded Exclusion criteria: those whose cultures subsequently were negative were withdrawn
Interventions	Children were assigned to 1 of 5 study groups, each group consisted of 10 patients. Group 1 received no antimicrobial agents (control group). Group 2 received ampicillin 100 mg/kg/day. Group 3 received oxytetracycline 50 mg/kg/day. Group 4 received chloramphenicol 50 mg/kg/day. Group 5 received erythromycin (estolate) 50 mg/kg/day. All antimicrobial drugs were administered in 4 divided doses at 6‐hourly intervals for at least 7 days, by oral route except in those who were comatose or with severe vomiting in which parenteral route was used Pertussis hyperimmune globulin was administered to some of the patients according to physician's preference
Outcomes	Microbiological eradication, clinical improvement, duration of the illness
Notes	The second part of the study regarding antimicrobial prophylaxis against pertussis was excluded since it was not a randomised controlled trial Immunisation status: only 9 (19%) of the 50 children studied had received any previous injection of pertussis vaccine. Only 2 children out of 50 studies had previously received 3 DTP injections and their illness appeared milder than non‐immunised children
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation: not stated
Allocation concealment (selection bias)	Unclear risk	Unclear risk
Blinding (performance bias and detection bias) All outcomes	High risk	Blinding of Intervention: no. Blinding of outcome measure: no
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete follow up: yes