ab Slepushkin 1991

Methods	Randomised placebo‐controlled trial carried out in the 1987‐1988 season in Leningrad, former USSR on school children aged 8 to 15 years to test live CA vaccine, with inactivated vaccine with intranasal and intramuscular placebo (data by placebo not presented split). There was an influenza A (H3N2) and B mixed epidemic reported in Slepushkin 93 but the vaccines did not contain any B antigen. Influenza A peaked in mid Jan to mid Feb, whereas circulation of influenza B was constant
Participants	241 healthy boarding school children aged 8 to 15 years (97, 56, 88 (for CA, bivalent vaccine and placebo at first dose and 95 and 78 for CA and placebo). The attrition between first and second dose of both active arm and placebo is not explained
Interventions	Intranasal live CA A/47/F derived from A/Philippines/2/82‐like (H3N2) and A/Leningrad/134/47/57 (H2N2) or intramuscular normal saline placebo or bivalent vaccine (containing A/Philippines/2/82‐like (H3N2) and A/Chile/1/83/ (H1N1) or intranasal allantoic fluid placebo. IM applications took place only once, whereas internasal twice approximately 4 weeks apart
Outcomes	Temperature Local reactions Serological Paired sera and "micro neutralisation test". Convalescent sera only on those children who reported with ILI symptoms to the school nurse Effectiveness N/A in Slepushkin 1991, effectiveness was reported in Slepushkin 1993 for school 1: those children reporting with ILI (systemic illness or rhinitis or pharyngitis) symptoms had convalescent sera taken. Also reported are data from another school in the trial with asymptomatic cases (i.e. no symptoms but antibody rises). This is strange as the asymptomatics are all occurring in 1 school and the explanation is in the text: data on clinical illness were not collected. DATA NOT EXTRACTED Safety Temp (37.1°C to 37.5°C), local reactions, headache, sore throat, cough, head cold
Funding Source	Government
Notes	The authors conclude that "The inactivated vaccine was found to be superior to the live one in its capacity to stimulate humoral immunity studied by HI, EIA and micro‐neutralisation tests. In 69.7% of the children given the inactivated vaccine, seroconversion to the vaccine strain was detected by 2 or three methods of antibody titration used." Randomisation and attrition are not explained. Briefly reported study but clear text. The authors checked harm data against seroconversion, to ensure that for example temperature was not associated with seroconversion i.e. with infection. Unfortunately no effectiveness data are reported. Follow‐up not described. Problem with data collection and surveillance in school 2. In the 1993 paper the authors report efficacy as 13% (P = 0.82) for 2 doses of CA and 73% (P = 0.08) for 1 dose of bivalent vaccine. This relates to school 1. They also report an efficacy estimate for school 2 but this is likely to be highly unreliable
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Insufficient descriptions
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blinding
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not described
Summary assessments	Unclear risk	Randomisation and attrition are not explained