NoroSTAT Data Table

The following table shows the data for suspected and confirmed norovirus outbreaks reported by state health departments in Alabama, Massachusetts, Michigan, Minnesota, Nebraska, New Mexico, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Virginia, Wisconsin, and Wyoming to CDC through the National Outbreak Reporting System (NORS) by week of illness onset, 2012-2023*†‡¶§.

Norovirus Outbreaks Reported by State Health Departments by Week of Illness Onset, 2012-2023

 

Norovirus Outbreaks Reported by State Health Departments by Week of Illness Onset, 2012-2023
Week Minimum, 2012-20 Maximum, 2012-20 Range, 2012-20 2020-21 2021-22 2022-23
1-Aug 1 10 9 0 2 6
8-Aug 2 17 15 1 2 3
15-Aug 3 12 9 0 4 6
22-Aug 4 10 6 2 1 5
29-Aug 0 12 12 1 4 2
5-Sep 4 9 5 0 3 7
12-Sep 5 14 9 1 4 9
19-Sep 4 11 7 1 7 10
26-Sep 4 17 13 0 3 6
3-Oct 2 14 12 1 5 5
10-Oct 4 16 12 0 8 10
17-Oct 4 17 13 0 2 8
24-Oct 4 16 12 1 7 9
31-Oct 11 26 15 0 7 11
7-Nov 6 26 20 2 6 12
14-Nov 14 26 12 0 7 10
21-Nov 10 40 30 0 5 11
28-Nov 27 59 32 1 15 9
5-Dec 33 64 31 1 12 19
12-Dec 25 84 59 0 28 15
19-Dec 14 55 41 0 11 12
26-Dec 23 69 46 1 15 15
2-Jan 29 91 62 5 14 25
9-Jan 28 66 38 3 7
16-Jan 31 90 59 3 15
23-Jan 40 83 43 4 33
30-Jan 43 65 22 14 44
6-Feb 41 71 30 9 42
13-Feb 34 61 27 17 68
20-Feb 23 69 46 9 56
27-Feb 32 78 46 13 101
6-Mar 32 65 33 21 54
13-Mar 32 51 19 20 71
20-Mar 11 55 44 26 61
27-Mar 10 57 47 20 53
3-Apr 6 56 50 28 58
10-Apr 1 33 32 30 37
17-Apr 1 32 31 24 35
24-Apr 3 28 25 17 38
1-May 2 27 25 17 30
8-May 0 28 28 19 22
15-May 0 31 31 14 16
22-May 0 18 18 6 9
29-May 0 12 12 11 4
5-Jun 0 11 11 8 1
12-Jun 2 12 10 5 4
19-Jun 1 12 11 8 8
26-Jun 1 9 8 6 6
3-Jul 2 10 8 5 2
10-Jul 1 13 12 11 7
17-Jul 0 11 11 4 2
24-Jul 2 11 9 3 4

*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.

¶Nebraska joined the NoroSTAT network at the start of the 2019-20 seasonal year; 2012-2019 data from this state have been added for comparison.

§Alabama and North Carolina joined the NoroSTAT network at the start of the 2022-23 seasonal year; 2012-2022 data from these states have been added for comparison.