A resource- and labor-intensive county-wide
outbreak of pertussis, Wisconsin, 2003-2004:
high impact on the adolescent population.
Mark J. Sotir1, Diane L. Cappozzo2, Carol E. Schmidt2,
David M . Warshauer3, Jean Zastrow1, Tim Monson3,
Jeffrey P. Davis1
1Wisconsin
Division of Public Health
2Fond du Lac Health Department
3Wisconsin State Laboratory of Hygiene
National Immunization Conference
Washington, D.C., March, 2005
Background
Steadily increasing reported incidence of pertussis
among adolescents and adults since 1980’s
Large community-wide pertussis outbreak in
Fond du Lac County, Wisconsin
Outbreak interval: May, 2003 and February, 2004
Extensive response from local and state agencies
Objectives
Describe the epidemiologic features of the outbreak
Use data to address current pertussis-related issues
Methods
Health department personnel conducted patient follow-up
Standardized report form to collect data: signs and
symptoms, onset dates, intervention dates, exposure
source and contact information, antibiotic treatment,
vaccination history
Methods
Nasopharygeal swab specimens: 2 swabs (calcium
alginate for culture, Dacron for PCR)
Laboratory confirmation: isolation of Bordetella pertussis
in culture (C) or positive polymerase chain reaction (PCR)
assay
Pulsed field gel electrophoresis (PFGE) of isolates
Methods
CSTE/CDC pertussis case definitions applied
Data submitted to WDPH, entered or merged into Excel
database, converted to SAS file and analyzed using SAS
software (Version 8.2)
Incidence calculated using July 1, 2003 population
estimates
Fond du Lac County pertussis outbreak, cases by age
group and cough onset by two week interval, May, 2003 to
January, 2004
70
Number of Cases
60
50
40
30
20
10
0
5/1-5/15
6/1-6/15
<10 years
15-19
10-14
>19
7/1-7/15
8/1-8/15
9/1-9/15
10/1-10/15 11/1-11/15 12/1-12/15
Time Period
1/1-1/15
Fond du Lac County, Wisconsin pertussis
outbreak, May, 2003 - February, 2004
• County population 97296
• 313 case patients
193 (61.7%) laboratory confirmed
120 (38.3%) confirmed epi-link or probable
• 159 (51%) female
• Median age: 14 years (range: 1 mo - 70 yrs)
• 3 hospitalized (all infants, total 11 days)
• 0 deaths
• 37 (12%) of cases associated with high school
weight room use, 33 were 15-19 years old, 2 were
unvaccinated
Case patient clinical data Fond du Lac County
pertussis outbreak, 2003-04
Maximum n = 313
Symptom/sign
Cough
Paroxysms
Whoop
Post-tussive vomiting
Sleep disturbance
Encephalopathy
Hospitalization
% yes^
99%
58%
37%
31%
89%
0%
1%*
^Of known responses
*Three infants hospitalized for total of 11 days
Known vaccination histories (n=193)
Fond du Lac County pertussis outbreak
# doses
# case pts
% (of 193)
0
4
2.1
1
3
1.6
2
2
1.0
3
4
2.1
4
22
11.4
5 or more
158
81.9
Schools with > 1 case of pertussis while in
session, Fond du Lac County pertussis outbreak,
May, 2003 - February,2004
School Type Number of
Schools
High
3
Range:
cases per
school
1-69
Total cases
High: special
4
1 each
4
Middle
6
1-37
92
Elementary
11
1-14
36
All K-12
24
1-69
204
72
Case patient ages, Fond du Lac County pertussis
outbreak, May, 2003 - February,2004
Age group
#
<1
7
2-5
14
6-9
20
10-14
136
15-19
84
>19
50
Unknown
2
TOTAL
313
10 -19
> 10
County wide attack rate all ages: 322
%
2%
4%
6%
43%
27%
16%
1%
70%
86%
/ 100000
Age (years)
*cases/100,000 population
20-24
18-19
16-17
14-15
12-13
10-11
8-9
6-7
4-5
2-3
Cases/100,000
population
3000
2500
2000
1500
1000
500
0
1 or less
Fond du Lac County, Wisconsin pertussis outbreak,
age group specific incidence during the outbreak
interval, May 2003-January, 2004
Age (years)
*cases/100,000 population
>79
70-79
60-69
55-59
50-54
45-49
40-44
35-39
30-34
140
120
100
Cases/100,000
population
80
60
40
20
0
25-29
Fond du Lac County, Wisconsin pertussis outbreak, age
group specific incidence during the outbreak interval,
May 2003-January, 2004
Positive and total specimens submitted for
B. pertussis testing, July,2003-January,2004
Interval
# tested
# +% of +
%+
7/26-8/30
199
29
24
8/31-10/4
37
2
5
10/5-11/8
81
20
25
11/9-12/13
12/14-1/17
Total
2496 76%
133 69%
5
389
8
2
3122
192
6
Fond du Lac County pertussis cases by
laboratory confirmation status, 2003-04
70
Number of Cases
60
50
40
30
20
10
0
5/1-5/15
6/1-6/15
7/1-7/15
Laboratory confirmed
Not Laboratory Confirmed
8/1-8/15
9/1-9/15
10/1-10/15
Time Period
11/1-11/15
12/1-12/15
1/1-1/15
Comparison of PCR and culture for B. pertussis in
paired samples, Fond du Lac outbreak, Wisconsin
State Laboratory of Hygiene, 2003
PCR
Positive
Negative
Equivocal
Culture
Positive Negative
79
94
8
40
3
13
PCR sensitivity:
Culture sensitivity:
94%
49%
PCR and bacterial culture test positivity and concordancy
by time between cough onset and specimen collection,
Fond du Lac County, WI, 2003-2004
Test
results
Time between cough onset and specimen
collection
< 7 days
8-14 days
15-21 days
>21 days
PCR +
107 (78%)
43 (80%)
14 (61%)
14 (58%)
PCR -
31 (22%)
11 (20%)
9 (39%)
10 (42%)
Culture +
60 (42%)
21 (40%)
5 (25%)
3 (14%)
Culture -
82 (58%)
32 (60%)
15 (75%)
19 (86%)
56%
52%
PCR / C
concordant
50%
43%
PFGE patterns among Bordetella pertussis isolates, Fond
du Lac County, WI, July, 2003-January, 2004
PFGE
Pattern
CYXX01007*
CYXX01046*
CYXX01013**
Total
Month of cough onset
July-Aug Sept-Jan
10
FDL
USA^
Total (%) 1998-2001
51
51 (68%)
6%
13
23 (31%)
5%
1
1 ( 1%)
40%
75 (100%)
*not previously observed in WI
**32% of 79 isolates in WI tested prior to FDL outbreak
^Cassady PK et al (Abst) 7th Int’l Symposium on Pertussis (2002)
Median days between events, Fond du Lac County
pertussis outbreak, comparison of early and late
outbreak cases, May, 2003 - February, 2004
Event 1
Event 2
Cough
Treatment
onset
initiation
Paroxysms Treatment
initiation
Cough
Specimen
onset
collection
Cough
Reporting
onset
to LHD
Specimen
Reporting
collection
to LHD
Median (d)
E1 to E2
First third
10.5
Median (d)
E1 to E2
Last third
4
4.5
2
8
4
17
7
2
3
Estimated public health, case finding and
prevention costs for 313 cases of pertussis,
Fond du Lac County , WI, May 2003-February 2004
Cost categories Av cost/case
Lab tests
Antibiotic
prophylaxis
Public health
staff time
Total
(comment)
$1032 (2807 NP swab specs
@ $115/spec for PCR,
culture, admin:
Subtotal $323035)
$740 (4687 treatments
@ $49.43 AWP for azith.
Subtotal: $231678)
$217 (LHD 900 hrs: $36000
DPH 716 hrs: $31900)
$1989*
*not included: administrative disruption (schools,
social, athletic) or PPE
Conclusions
• Large community outbreak, widespread
morbidity that was very difficult to control
• Striking occurrence of pertussis among
adolescents.
–Impact of illness in two unvaccinated adolescents.
–Weight room related amplification of transmission.
• Mild but not insignificant impact among those
recently fully protected
• Substantial impact on schools and families
• Substantial impact on the public health and
health care communities
• “Steep learning curve” among clinicians
Conclusions (continued)
•Powerful effect of enhancements in diagnostic
technology (PCR) facilitating more sensitive
and rapid testing
• 62% of the reported cases in Fond du Lac
County were lab confirmed
•Focal occurrence in higher risk settings
during this community-wide outbreak required
sustained, focused control measures (schools,
health care settings)
Needs
• National and state guidelines providing
clearly stated endpoints and expectations for
pertussis prevention and control with
consideration of concerns regarding antibiotic
resistance and impacts associated with
enhanced diagnostic technology
• Provision of acellular pertussis component
containing vaccine for routine booster
vaccination in adolescents would be valuable
and acceptance is likely to be good . Benefits
would be substantial among: families, schools,
public health systems, health care systems and
insurers, businesses and many other settings
Acknowledgements
Special thanks to:
Warren Post, M D, Kayla Ericksen and
Mary Wedig, Fond du Lac, WI
Terry Kurzynski, Wisconsin State Laboratory of
Hygiene, Madison, WI
Mark Wegner, M D, Dan Hopfensperger, Jeff
Berg, Jerry Gabor, Andie Newman, DVM, and
Cindy Walker, Wisconsin Division of Public
Health, Madison, WI
Minimum estimated staff-related care and isolation
costs at county’s largest health care provider
$16,900: Medication for staff (157: illness or contact)
$11,000: Laboratory testing- 220 symptomatic staff
- all tests negative
$1,200: ER or urgent care assessment of illness
$49,450: Leave for furloughed staff
not est: Cost of replacement workers
not est: Cost of personal protective equipment
not est: Outbreak- related administrative,infection
control staff and PR costs
Costs greatly exceed $78000
Evaluation of the Economic Impacts of
the Fond du Lac County Pertussis
Outbreak
Overall Costs for 107 Cases of Pertussis,
Monroe County, New York, 1989-1994
Cost Categories
Physician visits
Direct
Indirect
Subtotal
Laboratory tests, direct
Medications
Antibiotics
Symptomatic
Subtotal
Emergency department visits
Direct
Indirect
Subtotal
Hospitalization
Direct
Indirect
Subtotal
Additional child care
Lost workdays
Total
Total Cost ($)
14355
13079
27434
2611
11780
10272
22052
5175
1845
7020
176702
17066
193758
3665
124312
381052
Pichichero and Treanor. Arch Pediatr Adolesc Med. 1997;151:35.
Economic Burden of Pertussis on Adults
Through Illness or Child Care Responsibilities
Adult
Workdays
(No. of
Families)
Lost Workdays
Average
Cumulative
Total
Families
with Added
Child Care
Costs (%)
Average
Added
Child Care
Costs ($)
No (51)
NA
NA
6
54
Yes
1 adult (50)
2 adults (4)
8.3
44
408
350
16
25
482
400
No data (2)
NA
NA
NA
NA
Pichichero and Treanor. Arch Pediatr Adolesc Med. 1997;151:35.
Cost Among Working Parents
Reason For
Work Loss
Days Lost
Per Working
Parent (mean)
Working
Parent
Affected
Average
Cost Per
Family ($)
Total
Cost For
Work Loss ($)
Ill family member at home
6
31
767
23780
Care for hospitalized infant
6
4
1025
4100
Ill family member brought to
Physician's office
Emergency department
1.7
0.7
35
5
282
111
9881
554
Total
Lee and Pichichero. Arch Fam Med. 2000;9:989.
38315
Productivity Among 42 Working Parents With
No Lost Workdays
Work
Productivity (%)
Working
Parents
Duration Per
Working Parent
(mean days)
Total Cost
For Lost Work
Productivity (%)
100
18
0
0
75-99
16
47
31078
50-74
4
38
12546
25-49
5
40
24846
<25
0
0
0
Total
Lee and Pichichero. Arch Fam Med. 2000;9:989.
68470
Costs for 87 Pertussis Cases, Monroe County, New York
Lee and Pichichero. Arch Fam Med. 2000;9:989.
Category
Medical costs ($)
Physician office visit:
ED visits
Hospitalization
Indirect costs for
visits/hospitalization
Subtotal
Laboratory ($)
Culture
DFA
Serology
Subtotal
Medication ($)
Antibiotic treatment
Symptomatic
Subtotal
Subtotal by age group ($)
Cost per case ($)
Parental work loss ($)
Loss of work days
Loss of Productivity
Additional child care
Household prophylaxis
Total
Adolescent
(n = 29)
Adult
(n = 6)
Subtotal (including
infant and child)
Total
Cost ($)
52107
3060
0
0
2788
405
0
0
369
10845
1303
20576
14435
47159
377
319
170
78
66
68
1131
957
884
2972
536
115
99
0
1441
435
1876
7368
254
1085
181
23780
68470
340
1206
23780
68470
340
1206
145903
Estimated case related costs for 313 cases of
pertussis, Fond du Lac County , Wisconsin,
May 2003-February 2004
Cost categories
Av cost/case (comment)
MD visits
Lab tests
Medications
$256* (52% direct)
$105 (PCR + culture)
$206* (1.16 Abx Rx/pt 53
53% Abx 47% Sx)
ER/urgent care
$66*
(74% direct)
Hospitalization
$141 (3 hosp, 11d)
Add’l child care
$100
Lost work days
$1162* (not include
lost
productivity)
Total
$2036
*projected from Pichichero and Treanor, Arch Pediatr
Estimated case related costs for 313 cases of pertussis, Fond
du Lac County , Wisconsin, May 2003-February 2004
med
group work adj
Age group
#
costs* total
loss** total^
<1
7
$2822 $19754
2-5
14
308
4312
6-9
20
308
6160
10-14
136
254
34544
15-19
84
254
21336
>19
50
181
9050
Unknown
2
306
612
TOTAL 313
95768
TOTAL per case
306 545
1702
* per patient direct and indirect health care, lab and meds based
on 1996 costs (Lee and Pichichero, Arch Fam Med; 2000:9:989)
** per patient parent work loss,productivity loss, child care
costs expressed as multiplier (1.78) of group med costs
^ group med plus work loss amounts doubled for 2004 cost
adjustment
Estimated costs for 313 cases of pertussis, Fond du
Lac County , Wisconsin, May 2003-February 2004
Cost
categories
Case related
costs
Public health
& prevention
Total
Crude
estimated
outbreak costs
Average
cost/case
Method A
$2115
Average
% cost/case
Method B
51 $1702
$1989
49
$1989
$3980
$3691
$1245740
$1155283
%
46
54