Figure 2:

Forest plot of placebo-controlled RCTs reporting proportion of participants experiencing 1 or more acute respiratory infection.

*This analysis includes data from the subset of ViDiFlu trial participants who were randomised to vitamin D vs. placebo control. **For this trial, participants were asked to report the occurrence of ARI during the one month prior to completing each annual urvey (max surveys=5). The numerator is the number of participants who reported an ARI on at least one survey. The ARI outcomes for participants who completed fewer than 5 surveys and who did not report an ARI (N=2239; 14%) were estimated based on the % affected among those who completed all 5 surveys (N=12152; 76%).