ab Slepushkin 1974.

Methods	Placebo‐ and do nothing‐controlled emergency randomised trial of live attenuated oral influenza vaccine carried out during the 1970‐71 season in Smolensk, USSR. During January 1971, at the beginning of an epidemic of influenza in the town, oral vaccination was carried out as an emergency on organised groups of children of nursery school age (1 to 3 years), and it appears that this study, carried out only in 2 arms, is the one for which we have data reported in the tables. The vaccine was given 2 to 3 times with an interval of 10 to 15 days. There appears to be another study included in the report to assess the effectiveness of the vaccine(s) in inducing interferon (data not extracted).
Participants	The children in each establishment (children's nurseries, nursery groups in larger schools) were selected on a medical basis, and their temperature was measured. Although the text states that "Three equal groups of healthy children were formed at random", the tables report 571 and 552 children in the vaccine and UV groups, respectively. It could be that the 3‐arm trial is different from the trial undertaken in January 1971, but the text is very confusing. There may even be a fourth study, with again 3 arms.
Interventions	For the vaccination, 2 types of the oral influenza vaccine were used, which were analysed at the Moscow Institute of Virological Preparations. The vaccine was composed of the strains of the influenza virus A2/Istra 10/96 and B/Liks 59, the infectious titre 10 exp.5.5 (the "two types" are not further discussed or reported). The single dose of the emergency prophylaxis vaccine for children was 1 mL for children aged 1 to 3 years, 2 mL for children aged 3 to 7 years, and 3 mL for children aged 8 to 16 years.
Outcomes	Serological "In order to determine antibodies, blood serum was taken from those who had been inoculated, before vaccination and between 21 to 30 days after its completion. The blood serum was tested in a reaction of the inhibition of the hemagglutination with 1% red corpuscle from chickens and four units of hemagglutinins of the virus when the antigen was put into contact with the antibodies for two hours" Effectiveness Follow‐up was 45 days. The children in the first group received the live influenza vaccine, and the second group received the medium no. 199, applied in the capacity of placebo. The third group were those who were not inoculated. Records were maintained for each child containing the date of inoculation, the type of vaccine, and also information about reactions to the vaccine. This included the results of the contraction of acute respiratory illnesses, starting from 10 days after the completion of the inoculations. Study 1 Raised temperature up to 37.5 °C, number of days after vaccination not defined Raised temperature > 37.5 °C, number of days after vaccination not defined Contraction of influenza and other acute respiratory illness >/= 10 days after inoculation 4‐fold rise in haemagglutination antibody titre (not for data extraction) Study 2 Emergency prevention of illness in first 15 days after vaccination (data not extracted; confounders, some children must have been sick over period of administration of 3 doses of vaccine, also no placebo arm carried out) Safety "The reactogenicity of the vaccine was determined by measuring daily the temperature in certain groups of those who had been inoculated"
Funding Source	Unclear
Notes	The authors conclude: "The establishment of the weak reactogenicity of the Moscow Scientific Research Institute of Virological Preparations’ (MNIIVP) live oral influenza substance for children aged 1 to 3 years and children of school age The study of the efficacy of MNIIVP’s live oral influenza vaccine as an inductor of endogenic interferons In 1970, during the rise in the cases of influenza and acute respiratory illnesses, administering the vaccine twice and three times reduced the rate of illness in pre‐school childrens’ establishments by twice, compared with those not vaccinated and by 1.5 times compared with the group of children who received placebo During the winter rise in the number of cases of respiratory virus infections in 1972, MNIIVP’s live oral influenza vaccine reduced the number of cases in the pre‐school group by 10.9 times after the first administration and by 4.4 times after the second. No noticeable effect was recorded after the third administration of the vaccine (index of efficacy 1.3) The index of efficacy of the live oral influenza vaccine used for the emergency prophylaxis of school children was precisely 4.0 and 2.7, after the first and second administrations respectively Using complex prophylactic methods (the routine immunisation in autumn, combined with the emergency prophylaxis) increased the efficacy of the live oral influenza vaccine by 2 times MNIIVP’s live oral influenza vaccine substance is recommended for extreme prophylaxis of influenza and viral acute respiratory illnesses in pre‐school (aged from 1 to 7 years) and school aged children" The text is so confusing that only the data from the tables have been extracted. However, we are not sure of their relationship with the text.
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	Not described
Summary assessments	High risk	Insufficient information to assess study design