Hsieh 2006.

Methods	Generation of allocation sequence: unclear Allocation concealment: unclear Blinding: single (participants) Inclusion of all randomized participants: adequate; 100% (no loss to follow up) Length of follow up: 8 weeks
Participants	Number: 219; 97 naive (aged 20 to 23 years) and 122 previously vaccinated participants (aged 24 to 65 years) Inclusion criteria: healthy adult Exclusion criteria: pregnancy; severe eczema; human immunodeficiency virus (HIV) infection; history of live‐attenuated virus vaccination within 60 days; receipt of blood products or immune globulin within last 6 months; household contact; sexual contact or occupational exposure to pregnant women
Interventions	Lister vaccine, Elstree strain, produced in 1981 or earlier by the Centers for Disease Control Taiwan For naive participants: 1. Undiluted vaccine 109 plaque‐forming units (PFU) 2. 1:5 dilution 3. 1:10 dilution For previously vaccinated participants: 4. Undiluted vaccine 109 PFU 5. 1:10 dilution 6. 1:30 dilution
Outcomes	1. Success rate 2. Humoral response and T‐cell response (measured by vaccinia‐specific CD69 expression on T‐cell subsets) 3. Adverse events
Notes	Location: China Significant neutralizing antibody titre defined one that caused a 60% reduction in pock count Significant antibody response defined as positive seroconversion or ≥ 4‐fold rise of vaccinia‐specific antibody titre