NoroSTAT Data Table

The following table shows the data for suspected and confirmed norovirus outbreaks reported by state health departments in Massachusetts, Michigan, Minnesota, New Mexico, Ohio, Oregon, South Carolina, Tennessee, Virginia, Wisconsin, and Wyoming to CDC through the National Outbreak Reporting System (NORS) by week of illness onset, 2012-2019*†‡.

Norovirus Outbreaks Reported by State Health Departments by Week of Illness Onset, 2012-2019
Week Minimum,
2012-2017
Maximum,
2012-2017
2017-2018 2018-2019
1-Aug 1 6 5 8
8-Aug 3 14 10 4
15-Aug 4 10 5 6
22-Aug 4 7 7 8
29-Aug 2 4 2 7
5-Sep 2 8 8 4
12-Sep 4 10 7 11
19-Sep 4 9 5 8
26-Sep 5 16 3 6
3-Oct 2 8 14 6
10-Oct 4 13 11 13
17-Oct 5 15 5 10
24-Oct 5 14 11 11
31-Oct 12 21 15 11
7-Nov 5 27 20 11
14-Nov 12 25 16 20
21-Nov 10 32 12 38
28-Nov 24 57 32 48
5-Dec 32 49 51 61
12-Dec 33 44 74 75
19-Dec 19 47 46 37
26-Dec 13 46 57 69
2-Jan 34 73 72 79
9-Jan 37 58 64 64
16-Jan 43 61 76 57
23-Jan 40 74 53 59
30-Jan 47 62 58 48
6-Feb 35 64 48 50
13-Feb 52 63 35 49
20-Feb 47 70 24 44
27-Feb 27 94 33 67
6-Mar 32 73 35 52
13-Mar 34 67 44 48
20-Mar 41 56 22 51
27-Mar 31 74 34 47
3-Apr 25 49 38 53
10-Apr 20 32 30 30
17-Apr 22 37 27 21
24-Apr 16 29 23 17
1-May 9 25 23 22
8-May 9 26 11 26
15-May 9 31 17 9
22-May 6 15 9 15
29-May 7 12 13 12
5-Jun 4 14 5 7
12-Jun 5 8 10 8
19-Jun 5 12 7 2
26-Jun 4 7 6 4
3-Jul 3 9 3 4
10-Jul 4 17 4
17-Jul 7 11 6
24-Jul 4 13 6

*Michigan and South Carolina joined the NoroSTAT network at the start of the 2015-16 seasonal year; 2012-15 data from these states have been added for comparison.

†Massachusetts and Virginia joined the NoroSTAT network at the start of the 2016-17 seasonal year; 2012-16 data from these states have been added for comparison.

‡New Mexico and Wyoming joined the NoroSTAT network at the start of the 2018-19 seasonal year; 2012-2018 data from these states have been added for comparison.