Table 2.

The Effect of Zinc Acetate Lozenges on the Rate of Recovery From the Common Cold in the 3 Included Trials

Trials	No. of Participants	Mean Duration of Colds in the Placebo Group (Days)	Effect of Zinc Lozenges on the Rate of Recovery
			RR	95% CI
Petrus et al [11]	101	7.1	1.77	1.16–2.7
Prasad et al [12]	48	8.1	7.5	3.5–16
Prasad et al [13]	50	7.1	22	7.7–64
The 3 Trials Pooled
Cox model: study as a random effect	199		3.1	2.1–4.7
Cox model: stratified by study	199		3.6	2.5–5.1
Cox model: study ignored as a clustering variable	199		2.6	1.9–3.5

Abbreviations: CI, confidence interval; RR, rate ratio.