Fig. 5

Daily humidity variables and risk of primary MERS by province in Saudi Arabia. Odds ratio (solid line) and 95% confidence limits (dashed lines) are plotted on the Y-axis, while time lags preceding case occurrence are plotted on the x-axis. The odds of primary MERS is increased 8 days after relatively low humidity (a), while the odds of primary MERS are decreased with higher humidity at 8–10 day lags (b-d). Asterisks indicate statistically significant odds ratios on corresponding days