aa Tannock 1984.

Methods	Controlled clinical trial, double‐blind, conducted in Australia during the 1981 influenza season. Follow‐up lasted from winter to spring. Influenza period was not defined. Volunteers were alternatively allocated to groups in a double‐blind manner. 6‐month sera were collected.
Participants	88 volunteer staff from Newcastle Hospital and the Commonwealth Steel Corporation: 56 treated and 32 placebo. Age of participants was 16 to 64.
Interventions	Trivalent subunit parenteral vaccine. Schedule and dose were: 7 µg each, 1 or 2 doses. Vaccine composition was: A/Brazil/11/78, A/Bangkok/1/79, B/Singapore/222/79. Placebo was saline for injection. Vaccine was recommended and matched circulating strain.
Outcomes	Influenza and adverse effects. A case of influenza was defined as a respiratory illness, retrospectively reported, associated with a 4‐fold antibody titre increase between postvaccination and postepidemic sera. Local side effects were redness, swelling, warmth or irritation, pain on contact, pain with pressure, continuous pain, or restriction of arm movement; systemic reactions were fever, chills, sweating, drowsiness, or insomnia.
Notes	1 dose and 2 doses were analysed together; very high dropout. Circulating strain was A/Bangkok/1/79. Safety data only were extracted. Government funded
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Inadequate
Allocation concealment (selection bias)	High risk	Inadequate
Blinding (performance bias and detection bias) All outcomes	High risk	Inadequate
Incomplete outcome data (attrition bias) All outcomes	High risk	Inadequate
Summary assessment	High risk	Inadequate