Pedroza 2009.

Methods	Randomised, double‐blind, placebo‐controlled, parallel‐arm trial for 56 days following first vaccination
Participants	Location: Mexico Number and age of participants: 163 (31 placebo, 132 influenza vaccine) children aged 5 to 9 years with mild intermittent and moderate persistent asthma Exclusion criteria: history of allergy to egg protein or thimerosal No details of past vaccination against influenza
Interventions	Vaccination type: intramuscular injection of trivalent inactivated influenza vaccine, 2 doses (28 days apart) Fluzone1 (Sanofi Pasteur) A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2), B/Victoria/504/2000. Placebo: injection used
Outcomes	Primary outcome: adverse events (systemic and local) Secondary outcomes: pulmonary function tests (force expiratory volume in 1 second (FEV1) 5 days after each vaccination) and immunogenicity
Notes	Sponsored by Sanofi Pasteur
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Single blind, the contents of the syringe were shielded from the participants and administered by a clinician who was not involved in assessment
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"All the data were recorded by research nurses and physicians who were not aware of the product administered to individuals in the study"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No details of drop‐outs