Figure 1.
Weekly norovirus notifications and Websök searches, Sweden 2006–2013.
Figure 1 represents for each week between week 27 2006 and week 26 2013, the norovirus notifications and online searches for the terms “kräk” (vomiting) and “vinterkräksjuka” (winter vomiting disease) expressed as weekly proportion of the yearly total after smoothing, standardisation and adjusting for trend. The blue line represents laboratory notifications, the red line represents online searches for “kräk” (vomiting) and the green line represents online searches for “vinterkräksjuka” (winter vomiting disease).
Figure 2.
Number of weekly norovirus laboratory notifications and Websök searches, Sweden, 2006–2013.
Dots represent the weeks the threshold for norovirus season onset is crossed. Figure 2 presents three separate graphs. The black graph represents laboratory notifications, the green graph represents online searches for the term “vinterkräksjuka” (winter vomiting disease) and the red graph represents online searches for the term “kräk” (vomiting). Each graph presents the number of notifications or searches per week between week 27 2006 and week 26 2013, along with a baseline and the 95% upper prediction interval line of the baseline. For each year, on each graph, the dots represents the week when the number of searches or notifications exceeded the 95% upper prediction interval line of the baseline, thus indicating when the onset of the norovirus season is detected in each case.
Table 1.
Week number when activity crossed the epidemic threshold for norovirus laboratory notifications, and searches for “kräk” (vomiting) and “vinterkräksjuka” (winter vomiting disease) in Websök along with number of weeks gained for each search term compared with laboratory notifications, Sweden, 2006/2007 - -2012/2013.
Table 2.
Sociodemographic characteristics of Vårdguiden.se users compared with the Swedish population, 2012.
Table 3.
Impact of norovirus outbreaks in hospitals and perception of web-based surveillance data according to 17 Swedish infection control teams, 2012/13.