ab Slepushkin 1988.

Methods	Randomised, single‐blinded, placebo‐controlled study conducted in a boarding school in Moscow in September to December 1984
Participants	107 healthy children 8 to 11 years old without a history of current illness were examined and judged eligible for study
Interventions	Attenuated influenza vaccine prepared by recombination of the cold‐adapted strain A/Leningrad/134/47/57 (H2N2) with A/Leningrad/322/79 (H1N1). Before use, lyophilised vaccine was diluted 1:2 with distilled water and administered intranasally by means of a Smirnov aerosol generator. Distilled water only was administered as placebo. 2 doses of 0.5 mL were administered 28 days apart. Vaccine titre was 102 EID50 for the first dose and 107 for the second. Children were randomly divided to receive vaccine or placebo. 58 children received the first dose of vaccine and 49 placebo. Of the 58 vaccinated children, 43 received second dose of vaccine, and 39 of 49 received second dose of placebo.
Outcomes	Serological Haemagglutination inhibition test against A/Brasil/11/78 and enzyme immunoassay Effectiveness N/A Safety "All children were observed for 5 days after each vaccination Axillary temperature was measured once each day and children were interviewed about the presence of eventual symptoms and visited at home in case of absence from the school"
Funding Source	Government
Notes	The authors conclude that despite the first dose being weakly immunogenic, the second dose response was much better, and the vaccine proved safe. Poorly conducted study: de facto unblinded, with unexplained attrition. Physical aspect of placebo and vaccine in coded vials differed, resulting in inadequate blinding. There is a strange subanalysis of respiratory symptoms classified as harms by arm after the first vaccination dose. The authors carried out nasal swabs in 10 children and found that 1 had tonsillitis and 5 had adenovirus rhinitis. Although the breakdown of these by arm is not reported, as this is an RCT, what surely matters is the difference in event between arms, even for harms. This leads us to suspect that the authors did not trust their own random allocation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	High risk	Not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unexplained losses to follow‐up
Summary assessments	High risk	Poorly conducted study: de facto unblinded, with unexplained attrition