Weekly pertussis update for Washington State

Weekly pertussis update for Washington State
2014 year to date (YTD) confirmed and probable cases reported through 11/1/2014 (week 44)
This update summarizes reports of pertussis in persons with 2014 onsets received by local health jurisdictions
(LHJs) during weeks 1-44, made visible to Washington State Department of Health (DOH) - Communicable
Disease Epidemiology, and containing sufficient information for a DOH case classification to have been
assigned.

There have been a total of 390 cases reported statewide through week 44, compared to 633 reported
cases in 2013 during the same time period. Dates for the 2013/2014 comparison were based on LHJ
notification date.
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
Sixteen counties have reported no pertussis activity so far in 2014.

Among the twenty-three counties with pertussis activity, the number of pertussis cases reported in a
given county so far this year ranges from 1 to 77, and the year to date rate of disease in a given county
ranges from 2.0 to 60.1 per 100,000 persons (see Table 1).
o

The median and mean county rates in counties reporting pertussis activity are 7.6 and 11.5 per
100,000 persons year to date, respectively.
The overall incidence year to date is 5.8 pertussis cases per 100,000 Washington residents with a rate
in infants under one year of age of 58.7 per 100,000 (see Table 2). Fifty-two infants under one year of
age were reported as having whooping cough and eleven of them were hospitalized. Of those
hospitalized, ten (91%) were three months of age or younger.
Table 1. WA State pertussis cases by county,
2014
County
Adams
Asotin
Chelan
Clallam
Clark
Cowlitz
Franklin
Grant
Island
King
Kitsap
Klickitat
Lewis
Okanogan
Pend Oreille
Pierce
Skagit
Snohomish
Spokane
Thurston
Walla Walla
Whatcom
Yakima
2010 OFM
Population
18,300
21,700
73,300
70,100
435,600
100,000
75,500
87,700
81,100
1,933,400
248,300
20,500
75,600
40,900
13,100
814,600
119,300
711,100
470,300
252,400
59,600
195,500
239,100
Number
of
cases
11
1
3
20
33
8
4
34
8
70
5
2
10
3
1
77
16
15
18
11
2
21
17
Rate per
100,000
persons
60.1
4.6
4.1
28.5
7.6
8.0
5.3
38.8
9.9
3.6
2.0
9.8
13.2
7.3
7.6
9.5
13.4
2.1
3.8
4.4
3.4
10.7
7.1
Table 2. WA State pertussis cases by age group,
2014
Age
Group
(years)
<1
1-4
5-9
10-13
14-18
19-24
25-44
45-64
65+
All ages
Note. Counties with no reported cases classified as confirmed or
probable, 2014: Benton, Columbia, Douglas, Ferry, Garfield, Grays
Harbor, Jefferson, Kittitas, Lincoln, Mason, Okanogan, Pacific, San
Juan, Skamania, Stevens, Whitman, and Wahkiakum.
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2010 OFM
Population
88,544
355,275
432,656
346,396
454,703
577,706
1,830,703
1,823,910
823,357
6,733,250
Number
of
Cases
52
72
68
50
52
28
47
17
4
390
Rate per
100,000
persons
58.7
20.3
15.7
14.4
11.4
4.8
2.6
0.9
0.5
5.8
% cases
by age
group
13.3
18.5
17.4
12.8
13.3
7.2
12.1
4.4
1.0
Recent Pertussis Incidence by County (July 2014 – September 2014 Onsets)
If you have a disability and need this document in a different format, please call 1-800-525-0127 (TDD/TTY 1-800-833-6388).
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DOH 348-254 November 2014