Figure 2. The network for multiple-treatments meta-analysis (MTM) includes all the randomized controlled trials that evaluate hemagglutinination-inhibition vaccine efficacy after the first or single dose.

Each node represents a treatment and is named with letters depending on whether the vaccine included aluminum (AL), non-aluminium adjuvant (Non-AL), or no adjuvant; and with numbers reflecting the administered hemagglutinin antigen per dose (in µg): 1.88–5.25, 7.5, 15, or 21–30. The size of each node is proportional to the total number of patients randomized. Links represent head-to-head comparisons between the linked nodes with the thickness being proportional to the number of trials reporting on each specific comparison.