Rotavirus IQS searches in the Unite

Rotavirus IQS searches in the United States and United Kingdom correlated strongly with rotavirus laboratory detections (r = 0.88 [P < .001] and r = 0.80 [P < .001], respectively). Rotavirus IQS data peaked within 3 weeks of the peak in laboratory detections of rotavirus in 6 of 7 seasons in the United States (except in 2010, when the IQS peak was 11 weeks before the peak in laboratory detections) and in 6 of 7 seasons in the United Kingdom (except in 2008, when the IQS peak was 4 weeks after the peak in laboratory detections).

In the United States, compared with prevaccine years, the regression model estimated a 39% decrease (95% CI, 28%–48%; P < .001) in weekly IQS data and 24% decrease (95% CI, 4%–40%; P = .023) in weekly laboratory detections in postvaccine years (Figure 1). In postvaccine years in the United States, search volume and laboratory detections had the strongest association (IRR, 1.96 for a 1% increase in IQS; 95% CI, 1.73–2.23; P < .001) when a lead of 1 week was introduced into the IQS data (ie, IQS data from weekx+1 regressed onto rotavirus laboratory data from weekx). In the United Kingdom, compared with prevaccine years, the regression model estimated a 23% increase (95% CI, 1%–50%; P < .042) in weekly IQS data and a 38% increase (95% CI, 16%–65%; P < .001) in weekly laboratory detections in postvaccine years.