cb Slepushkin 1994.

Methods	Cohort study to compare reactogenicity and immunogenicity in children vaccinated with live vaccine, inactivated vaccine, or placebo, carried out over 3 years in Novogorod, former USSR. No mention of randomisation is made, and the study was classified as a cohort. Allocation was on a school basis. A subgroup was inoculated each year of study prior to mass inoculations to determine reactogenicity and immunogenicity. Reactogenicity and immunogenicity results were analysed using "generally accepted methods" (Slepushkin and colleagues 1991, Ibid, 5: 372‐4).
Participants	Children aged 7 to 14 years
Interventions	1989: Soviet commercial bivalent vaccine A/Sichuan/2/87‐like (H3N2) and A/Taiwan/1/86‐like (H1N1) ‐ inactivated 1989: Soviet commercial bivalent vaccine A/Sichuan/2/87‐like (H3N2) and A/Taiwan/1/86‐like (H1N1) ‐ live 1990: A/Shanghai/11/87 (H3N2), A/Taiwan/1/86 (H1N1), B/Victoria/2/87 ‐ inactivated 1990: A/Shanghai/11/87 (H3N2), A/Taiwan/1/86 (H1N1), B/Victoria/2/87 ‐ live 1991: A/Shanghai/11/87 (H3N2), A/Taiwan/1/86 (H1N1), B/Victoria/2/87 ‐ inactivated 1991: A/Shanghai/11/87 (H3N2), A/Taiwan/1/86 (H1N1), B/Yamagata/16/88‐like ‐ live No placebo arm is reported in the third year, which is strange as there is a placebo arm reported for immunogenicity in Table 2. For the second year there is also a mysterious second inactivated vaccine that appears in the results tables. Data not extracted. To obtain live recombinant vaccine, cold‐adapted strains A/Leningrad/134/47/57 (H2N2) and B/USSR/60/69 were used as attenuation donors.
Outcomes	Serological Seroconversion (not extracted) Effectiveness N/A Safety Temperature reactions and local hyperaemia and infiltration after vaccination
Funding Source	Government
Notes	The authors do not draw clear conclusions, and it is difficult to understand what the purpose of the study was. Badly reported; no clear overall denominator, and safety data are reported for limited groups of participants with no clear sampling rule.
Risk of bias
Bias	Authors' judgement	Support for judgement
PCS/RCS‐Selection Exposed cohort	Unclear risk	No description
PCS/RCS‐Selection Non Exposed cohort	Unclear risk	No description
PCS/RCS‐Comparability	Unclear risk	No description
PCS/RCS‐Assessment of Oucome	Unclear risk	No description
Summary assessments	High risk	Insufficient information