Figure 1. The effects of herpesviruses, including VZV, HSV, CMV, and EBV, on the risk of stroke. OR indicates odds ratio, 95% CI indicates 95% confidence interval, and %Weight indicates the weight of each study. The vertical line in the middle represents the null effect line (OR = 1), indicating no statistical association between the studied factor and the outcome. Each horizontal line represents the 95% CI of each study. If the horizontal line of a certain study does not intersect with the null effect line (i.e., the 95% CI does not cross 0), it can be considered that there is a statistical association between the studied factor and the outcome. Abbreviations: yr: represents a year; wk: represents a week.