2009 H1N1 Influenza Summary Report –June 2010, Page 1
2009 H1N1 Mid-Term Review Winnebago County, Illinois
April 2009-February 2010
A Publication of the Winnebago County Health Department, June 2010.
2009 H1N1 Influenza Summary Report –June 2010, Page 2
Table of Contents
I. Executive Summary - 2
II. Background - 4
III. Purpose - 5
IV. Materials and Methods - 6
V. Influenza-Like Illness - 7
VI. Cases - 15
VII. Hospitalizations - 19
VIII. Percent of Hospitalizations - 23
IX. Laboratory Submissions - 25
X. Projected Estimates of Actual H1N1 Spread - 26
XI. Vaccine Coverage - 29
XII. Media Coverage - 33
XIII. Discussion - 37
XIV. Acknowledgments - 39
XV. Works Cited - 40
XVI. Additional Tables - 41
2009 H1N1 Influenza Summary Report –June 2010, Page 3
I. Executive Summary
The mission of the Winnebago County Health Department is to ―Prevent disease,
promote health and enlist the community in efforts to improve the health of all Winnebago
County residents.‖ This goal is achieved through routine inspections, health promotion
programs, health clinics, vaccinations and disease surveillance. In April of 2009, a unique
strain of the influenza virus, labeled 2009 H1N1, or commonly referred to as ‗Swine Flu,‘ was
detected in some of the citizens of Winnebago County. Detailed epidemiological surveillance
data, vaccine coverage and media coverage delivered during the 2009 H1N1 pandemic
follows. This document illustrates how the efforts of the Winnebago County Health
Department, in association with other public and private enterprises, responded to the 2009
H1N1 influenza pandemic, and the numbers, confirmed and suspected, with the spread of the
virus.
2009 H1N1 Influenza Summary Report –June 2010, Page 4
II. Background
In early April of 2009, Mexican health officials released multiple reports of febrile
respiratory illness. By mid-April, the Centers for Disease Control and Prevention (CDC) had
reports of similar infections. Laboratory findings determined to be from swine influenza A,
now known as novel 2009 H1N1 (H1N1) (1). US cases typically presented with a fever and
cough (1). Early numbers indicated the majority of cases were found in the children under the
age of 18 (2). This is different from seasonal flu, which typically affects those over 65 years in
age. People with certain pre-existing conditions, such as asthma and diabetes, were also
identified to be at significantly higher risk than those without those conditions (3).
Symptoms of the H1N1 flu are similar to seasonal flu. Although cough and fever were
the two main symptoms of the H1N1 flu, other symptoms included: shortness of breath,
fatigue, chills, sore throat, headache and vomiting (3). The incubation period for H1N1
influenza is also similar to seasonal flu, averaging from 2 to 3 days (3).
On April 28, 2009, the Chicago Department of Public Health identified the first case of
H1N1 flu in the city (4). On May 2, the Winnebago County Health Department received
confirmation of the first H1N1 case in a resident of the county. A communicable disease
investigation was initiated, questionnaires referencing symptom onset, symptom manifestation
and any potential disease source (work, school, etc.) were administered to all patients with a
confirmed positive H1N1 diagnosis. There appeared to be four different periods of the
pandemic since April 2009. The first period, or Wave 1, began with the first identified case in
the United States on April 21, to June 6, 2009. The period from June 6 to August 29, 2009 is
called the latent period, due to the decreased number of cases. The third period, August 30 to
December 12, 2009, is Wave 2, when case reports increased dramatically. From the period of
December 13 to February 27 are included in the post-wave period.
2009 H1N1 Influenza Summary Report –June 2010, Page 5
III. Purpose
This comprehensive report is intended to be an in-depth look at the H1N1 flu within
Winnebago County from April 2009 to February 2010. Topics covered include: Influenza-like
Illness (ILI), confirmed cases, reported hospitalizations, percentage of hospitalizations,
laboratory submissions, H1N1 projections and vaccine information. Data is current as of the
date of publication and data are subject to change.
2009 H1N1 Influenza Summary Report –June 2010, Page 6
IV. Materials and Methods
There were several methods of data collection, the first being INEDSS (Illinois National
Electronic Disease Surveillance System). Positive H1N1 cases were reported through the
INEDSS system, fax reports, and laboratory confirmation results. Questionnaires were
completed from interviews with confirmed cases (or if a patient interview was not possible, an
Infection Control Practitioner or family member) and entered in to appropriate data-collection
spreadsheets. ESSENCE (Electronic Surveillance System for the Early Notification of
Community-based Epidemics) data on ILI and discharge diagnosis from sentinel sites was
utilized, along with school absenteeism reports, CDC notifications, projections and reports.
2009 H1N1 Influenza Summary Report –June 2010, Page 7
V. Influenza-Like Illness
Influenza-Like Illness (ILI) is monitored by week on a year-round basis by
Epidemiologic and Communicable Disease staff at the Winnebago County Health Department.
Previous trends illustrate a peak in ILI activity which usually occurs during the traditional
influenza season (Week 41, October 11 of 2009, through Week 25, June 26 of 2010). With the
H1N1 flu, there were 2 separate peaks, the first occurring after the seasonal influenza peak of
the 2009 season and the second right at the beginning of the 2010 seasonal influenza season.
Figure 5.01 shows the ILI activity for Winnebago County. All ILI figures are calculated using
ESSENCE.
Figure 5.01
Note in the above graph the increase in ILI activity in weeks 16 through 19, fairly low
levels from week 20 through week 38, and the second large spike from weeks 39 through 49.
Figure 5.02, as seen on page 8, shows the association between Winnebago County and data
from the entire northern Illinois region.
2009 H1N1 Influenza Summary Report –June 2010, Page 8
Figure 5.02
The data are similar when comparing Winnebago County to regional data. However,
the ILI activity seen in Winnebago County is higher (18.1%) than the region (6.4%) during the
second peak. Figure 5.03, below, shows the ILI activity from week 15, 2009 through week 4,
2010 for Cook County, the city of Chicago, DuPage County, Kane County and Winnebago
County.
Much like Figure 5.02, Figure 5.03 has very similar peaks. Both DuPage and Kane
counties saw higher peaks than the region as a whole, much like the ILI activity in Winnebago
County. The first peak commences earlier in the other four jurisdictions than in Winnebago
County, but the second peak arrived at the same time, Week 43, in all five jurisdictions.
Figure 5.03
2009 H1N1 Influenza Summary Report –June 2010, Page 9
Figure 5.04
Figure 5.04, above, shows ILI activity for Winnebago County by the following age
groups: 0-4 years, 5-17 years, 18-64 years, and 65 years and over. For those groups 0-4 and
5-17 years, data was higher than the average, while activity for those aged 18-64 was slightly
below average. For those aged 65 and over, the data was near 0% for much of the H1N1
outbreak. For all four age groups, the first peak, the latent period, and the second peak are
easily identified. For more graphs showing the breakout of different age groups versus regional
or jurisdictional trends, refer to Appendix A.
As previously seen in Figure 5.01, there are 2 distinct peaks, with a period in between
with low levels of ILI activity. Figure 5.05 shows the breakout of ILI activity during Wave 1.
Figure 5.05
2009 H1N1 Influenza Summary Report –June 2010, Page 10
ILI peaked in week 17, at 4.2% of ED visits, for the region and in week 18, at 5% of ED
visits, for Winnebago County.
Figure 5.06
The data in Figure 5.06, above, show the continued decline, despite being high for the
summer. These levels remain constant in to Wave 2, with the large increase in ILI activity in
week 43.
Figure 5.07
This large increase in ILI activity in Figure 4.07 is mirrored in both regional and
Winnebago County data. Figure 5.08 shows the Wave 2 breakdown by jurisdiction within
Northeastern Illinois. To see other waves by jurisdiction, refer to Appendix A.
2009 H1N1 Influenza Summary Report –June 2010, Page 11
Figure 5.08
The increase in ILI activity is very similar in Figures 5.07 and 5.08, and provides a clear
illustration of the similarities between Winnebago, Kane and DuPage counties. Figure 5.09,
below, shows the breakout of ILI activity from week 50 of 2009 to week 8 of 2010. The
leveling out of ILI activity is shown after the end of the second wave.
Figure 5.09
Looking by age group during the separate waves exclusively for Winnebago County, it
is visible that the majority of ILI activity occurred in those in age groups 0-4 and 5-17.
2009 H1N1 Influenza Summary Report –June 2010, Page 12
Figure 5.10
Figure 5.10, above, shows the age breakout for Wave 1 in Winnebago County. The
levels of ILI activity are highest in the 0-4 year age group, at 16%. Figure 5.11, below, shows
the same trend, with some similar increases in the 5-17 year age group, at 7.4%.
Figure 5.11
2009 H1N1 Influenza Summary Report –June 2010, Page 13
Figure 5.12
Figure 5.13
The results from Figure 5.12, above shows an increase in ILI activity for the 0-4 year
age group, peaking at 29.1% (Week 42) of visits due to ILI, and an additional increase in ILI
activity for the 5-17 year age group, with the data peaking at 34.9% (Week 43) of visits for ILI,
completing the surveillance information by age. Figure 5.13, below, shows data that closely
resembles data from wave 1, but the decrease in activity from the second peak is apparent.
Proceed to Appendix A for further breakdowns of age by wave.
2009 H1N1 Influenza Summary Report –June 2010, Page 14
A second way ILI was tracked was through school absenteeism data. Schools were
requested to report daily absenteeism due to ILI to the health department. Overall, two school
districts were closed (Kinnikinnick and South Beloit) for 2 days each (5,6). Both of these
school districts serve the northern portion of the County. There were also elevated ILI rates in
the northern districts when compared to the Rockford Public School District. This is visible in
Figure 5.14, below.
Figure 5.14
There is a distinct peak at week 41 for the northern school districts, while the peak is
during week 43 for the Rockford Public School District. This data mirrors ILI activity in the
northern portion of the county as well.
2009 H1N1 Influenza Summary Report –June 2010, Page 15
VI. Cases
To date, Winnebago County has reported 234 confirmed cases of H1N1, resulting in 161
hospitalizations and contributing to 5 deaths. The range in ages varied, from one month to 85
years, with the average being 27.67 years (median 20.5). The majority of cases were female
(55%). The most common age group of all cases was the 5-17 group, followed by the 45-64
group. Figure 6.01, below, shows more detail on age range and percent of overall cases. The
rate of cases per 100,000 population is included in the far-right column.
Figure
6.01
Age Range 1 mo - 85 yrs
Mean 27.67 yrs
Median 20.5 yrs
Figure 6.02, left. The age range, mean and median for all
H1N1 cases in Winnebago County.
Gender N %
Male 105 45%
Female 129 55%
Figure 6.03, right. The gender breakdown of
all H1N1 cases in Winnebago County.
Figure 6.04, at left, shows the age
profile for all H1N1 cases in
Winnebago County. Forty-five
percent of all cases were under the
age of 18.
Age Range Total Cases n / % Rate
0 - 4 45 / 19% 218.35
5 - 17 62 / 26% 114.68
18 - 44 54 / 23% 49.05
45 - 64 55 / 24% 72.30
65 + 18 / 8% 45.67
Total 234 / 100% 77.93
2009 H1N1 Influenza Summary Report –June 2010, Page 16
As with national trends, there were several co-morbidities present in cases of H1N1 in
Winnebago County. The most common co-morbidity was that of asthma (29.5%), followed by
diabetes (13.0%). In addition, 2.4% of all H1N1 cases were pregnant.
Race Total Cases n / % Rate*
White 152 / 64.9% 59.42
African American/ Black 64 / 27.4% 176.05
Other 18 / 7.7% 222.97
Total 234 / 100% 77.93
Ethnicity Total Cases n / % Rate*
Hispanic 41 / 26.9% 131.95
Non-Hispanic White 111 / 73.1% 49.39
Total 152 / 100% 59.42
Figure 6.05
Figure 6.06
The above charts show the dispersal of H1N1 cases by Race (Figure 6.05) and Ethnicity
(6.06), respectively. *- Rate of cases per 100,000 population.
Below is the epi-curve of the positive H1N1 cases by date of onset of illness. It is fairly
visible, the two peaks, the first around week 21 and the second around week 42. The overlay is
of deaths attributable to H1N1.
Figure 6.07
2009 H1N1 Influenza Summary Report –June 2010, Page 17
Figure 6.08, below, shows the spatial distribution by zip code of all H1N1 cases as a rate
per 100,000 population.
Figure 6.08
- 0.00
- 1 - 32
- 32.1– 55
- 55.1 - 65
- 65.1 - 95
- 95.1 - 150
- 150+
All calculations in Figure 6.08 are as a rate per
100,000 population
2009 H1N1 Influenza Summary Report –June 2010, Page 18
The Figure 6.08 shows higher rates of H1N1 in areas that are more highly populated,
with the highest rate being in zip code 61104. Several surrounding zip codes were also fairly
high. Surprisingly, in the areas north of the city, where the first H1N1 cases were identified,
there are lower rates of H1N1. This may be due to underreporting or lack of severe
symptomology, as after July 24, only hospitalized cases and those who accessed care from
sentinel sites were reported. In addition, CDC recommendations stated that patients who felt ill
should refrain from seeing their physician and stay home and self-treat.
When looking at the H1N1 picture by period, the picture of the scope of the disease
becomes clearer. Figures 6.09 and 6.10 are age distributions for H1N1 during Wave 1 and
Wave 2, respectively. Of interest, Wave 1 shows the majority of cases were in those under the
age of 17, but during Wave 2, the majority was over the age of 18.
Figure 6.09
Figure 6.10
For more detail regarding H1N1 cases, refer to Appendix B.
2009 H1N1 Influenza Summary Report –June 2010, Page 19
VII. Hospitalizations
Winnebago County has seen 161 H1N1 related hospitalizations to date. As with the
overall case reporting, the age range for hospitalized cases was wide (1 month to 85 years).
The average age increased to 33.87 years from 27.67 in all cases (median 37.5, previously
20.5). The majority of hospitalizations were female (53%). The most common age groups
were 45-64, followed by 18-64. More detail on age range and percent of overall cases is
available in Figure 6.01, seen below. The rate of hospitalizations per 100,000 population is
included in the far-right column.
Age Range Total Hospitalizations n / % Rate
0 - 4 27 / 17% 131.01
5 - 17 27 / 17% 49.94
18 - 44 39 / 24% 35.43
45 - 64 50 / 31% 65.73
65 + 18 / 11% 45.67
Total 161 / 100% 53.62
Figure 6.01
Figure 6.02, left. The age range, mean and median for all
hospitalized H1N1 cases in Winnebago County.
Age Range 1 mo - 85 yrs
Mean 33.86 yrs
Median 37.5 yrs
Figure 6.03, right. The gender breakdown of
all hospitalized H1N1 cases in Winnebago
County.
Figure 6.04, at left, shows the age
profile for all hospitalized H1N1
cases in Winnebago County.
Thirty-Four percent of all cases
were under the age of 18.
Gender N %
Male 75 47%
Female 86 53%
2009 H1N1 Influenza Summary Report –June 2010, Page 20
Co-morbidity incidence in all hospitalized cases of H1N1 show elevated rates of asthma
(34.1%) and diabetes (16.4%), in addition to the 8.2% of hospitalized cases who were found to
be immunocompromised. In addition, 33.5% of those hospitalized were diagnosed with
pneumonia, either viral or bacterial.
Race Total Hospitalizations n / % Rate*
White 107 / 66.5% 41.82
African American/ Black 40 / 24.8% 110.03
Other 14 / 8.7% 173.42
Total 161 / 100% 77.93
Figure 6.05
Ethnicity
Total Hospitalizations
n / % Rate*
Hispanic 24 / 22.4% 77.24
Non-Hispanic White 83 / 77.6% 36.93
Total 107 / 100% 41.83
Figure 6.06
The charts above show the distribution of H1N1 hospitalizations by Race (Figure 6.05)
and Ethnicity (Figure 6.06), respectively (*- Rate of cases per 100,000 population). Two-thirds
of cases were reported to be white, while the remaining third were among people of color.
Additionally, nearly 15% reported themselves being of Hispanic origin.
The epi-curve, as seen below, shows the positive H1N1 hospitalizations by reported date
of onset of illness. While the first peak is small, the second wave is clearly visible. The
overlay is of deaths attributable to H1N1. Four out of the five deaths occurred during the second
wave.
Figure 6.07
2009 H1N1 Influenza Summary Report –June 2010, Page 21
The spatial distribution by zip code of all hospitalized cases in seen below in Figure
6.08. All rates are shown as cases per 100,000 population.
- 0.00
- 1 - 32
- 32.1- 45
- 45.1 - 55
- 55.1 - 65
- 65.1 - 91
- 91+
All calculations in Figure 6.08 are as a rate per
100,000 population
2009 H1N1 Influenza Summary Report –June 2010, Page 22
The data in this figure mirrors the data from the total case rate figure. The highest rates
of hospitalized cases were within the zip codes 61114 and 61102 (both within the City of
Rockford), with a reduced rate of positive cases in the Western half of the county.
When isolating just Wave 1 and Wave 2, it is clear to see the difference in ages hospitalized for
the two separate times. Figures 6.09 and 6.10 show this disparity. While in Wave 1, those
under the age of 18 make up over half the reported hospitalizations, in Wave 2 they account for
only a third of those reported as hospitalized.
Figure 6.09
Figure 6.10
For more detail regarding H1N1 hospitalizations, refer to Appendix C.
2009 H1N1 Influenza Summary Report –June 2010, Page 23
VII. Percent of Hospitalizations
Higher hospitalization percentages were present in the older age groups. This is
attributed to other infections and co-morbidities that are more prevalent in older populations.
Figure 7.01, below, shows the percent of cases hospitalized by age.
Age Range Total Cases Total Hospitalizations % Hospitalized
0 - 4 45 27 60%
5 - 17 62 27 44%
18 - 44 54 39 72%
45 - 64 55 50 91%
65 + 18 18 100%
Total 234 161 69%
Figure 7.01
Figure 7.02, below, shows the difference in percentage of hospitalization by gender.
There is only a minor difference in the data between females and males.
Gender Total Cases Total
Hospitalizations % Hospitalized
Female 129 86 67%
Male 105 75 71%
Total 234 161 69%
Figure 7.02
2009 H1N1 Influenza Summary Report –June 2010, Page 24
The percentage of hospitalizations was lower for African Americans than for other
races, but by ethnicity, the percentage for Hispanics was much lower than that for Non-
Hispanic whites. This is seen in Figures 7.03 and 7.04.
Race Total Cases Total Hospitalizations % Hospitalized
White 152 107 70%
African American/ Black 64 40 63%
Other 18 14 78%
Total 234 161 69%
Figure 7.03
Ethnicity Total Cases Total Hospitalizations % Hospitalized
Hispanic 41 24 59%
Non-Hispanic White 111 83 75%
Total 152 107 70%
Figure 7.04
When comparing by wave, there is a large discrepancy in the percentage of
hospitalizations. During Wave 1, the hospitalization percentage was 17%, while it was 85% in
Wave 2. This can largely be explained by the CDC guidance on July 24, 2009 that stated to
only test hospitalized cases for H1N1 (3). Further representations of hospitalization
percentages by wave can be found in Appendix D.
2009 H1N1 Influenza Summary Report –June 2010, Page 25
IX. Laboratory Submissions
In order to confirm an H1N1 diagnosis, a sample from the patient must be submitted for
testing. Early in the outbreak, all samples nationwide were sent to the CDC laboratories, but as
the outbreak grew in scale, state laboratories quickly became the primary way to test for H1N1.
Overall, Winnebago County submitted 1688 samples for testing from April 2009 through
February 27, 2010. One-thousand, three-hundred sixty-nine samples were submitted on behalf
of residents of the county, while the other 319 were from persons who resided outside the
county. Below, in Figure 8.01, is a graph showing the amount of specimens submitted, with the
percentage of positive specimens overlaid. The percent positive line is the number of
positive submissions divided by the number of overall submissions.
The week with the most submissions was week 43 (92 submissions), while week 23 had
the highest percentage of positive submissions (5 out of 8 for 62.5% positive). This number is
likely influenced by the CDC protocol at the time that was limiting the numbers of submissions
permitted to be tested.
2009 H1N1 Influenza Summary Report –June 2010, Page 26
X. Projected Estimates of Actual H1N1 Spread
Given that only hospitalized cases were tested for H1N1 during the majority of the
pandemic, the CDC developed a procedure to estimate the number of H1N1 cases based on the
number of hospitalized cases (7). According to Reed et al., the estimated number of H1N1
cases are drastically underreported when compared to the actual numbers of H1N1 cases in the
population (7). To calculate the number of H1N1 hospitalizations, reported hospitalization
numbers from April to December 12, 2009, were entered in to an equation that takes in to
account non-reported cases, non-tested cases and cases that may have received a false negative.
This calculated value was also used to determine the number of cases and number of deaths
attributable to H1N1. Figure 9.01, seen on page 27, shows the calculated estimates of cases,
hospitalizations and deaths for Winnebago County.
2009 H1N1 Influenza Summary Report –June 2010, Page 27
2009 H1N1 Projections Mid-Level Range Estimated Range
Cases
0-4 Years 16,169 11,480 to 23,768
5-17 Years 16,169 11,480 to 23,768
18-24 Years 6,587 4,677 to 9,683
25-49 Years 23,953 10,077 to 35,211
50-64 Years 22,756 16,157 to 33,451
65 Years and Older 10,779 7,653 to 15,845
Cases Total 96,412 68,453 to 141,726
Hospitalizations
0-4 Years 73 52 to 107
5-17 Years 73 52 to 107
18-24 Years 30 21 to 44
25-49 Years 108 77 to 159
50-64 Years 103 73 to 151
65 Years and Older 49 35 to 71
Hospitalizations Total 435 309 to 639
Deaths
0-4 Years 1.1 0.78 to 1.6
5-17 Years 1.1 0.78 to 1.6
18-24 Years 1.8 1.3 to 2.6
25-49 Years 6.5 4.6 to 9.5
50-64 Years 6.2 4.4 to 9.0
65 Years and Older 2.9 2.1 to 4.3
Deaths Total 26.1 18.5 to 38.3
Figure 9.01
Figure 9.01. Projections of H1N1 spread within Winnebago County.
2009 H1N1 Influenza Summary Report –June 2010, Page 28
Rates were calculated for the State of Illinois and the United States for comparison.
These comparisons are seen in Figures 9.02 and 9.03, respectively. Rates per 100,000
population were calculated to use as a comparative tool between jurisdictions.
Age Range Winnebago
Estimate
Winnebago
Rate*
Illinois
Estimate
Illinois Rate*
Percent
Difference
0-4 16,168 78,453 289,835 32,407 142%
5-17 16,168 27,858 344,329 13,863 101%
18-24 6,587 30,275 117,970 10,604 186%
25-49 23,953 22,431 386,247 8,457 166%
50-64 22,756 42,423 253,905 11,192 279%
65+ 10,779 27,346 103,598 6,576 316%
Total 96,412 32,110 1,495,885 11,595 177%
Figure 9.02
Age Range Winnebago
Estimate
Winnebago
Rate*
United States
Estimate
United States
Rate*
Percent
Difference
0-17 32,337 43,331 17,608,657 23,814 82%
18-64 53.296 28,629 31,904,109 16,682 72%
65+ 10,779 27,346 4,982,542 12,819 113%
Total 96,412 32,110 54,495,308 17,923 78%
Figure 9.03
2009 H1N1 Influenza Summary Report –June 2010, Page 29
XI. Vaccine Coverage
Beginning in early October, the CDC began shipping H1N1 vaccine to states, based on
population (8). Vaccine supply delivered to the Winnebago County Health Department was
disseminated through the Illinois Department of Public Health. There are 2 kinds of H1N1
vaccine: The flu shot, which is an inactivated vaccine, and the nasal spray, an attenuated virus.
Winnebago County began to receive shipments of H1N1 vaccine very slowly, starting the week
of October 19, late in Wave 2.
In order to vaccinate as many people as possible, the Winnebago County Health
Department worked closely with its community partners through clinics, media relations and
vaccine distribution. Below is Figure 10.01. This figure shows the cumulative amounts of
vaccine received by the Winnebago County Health Department, the amount of vaccinations
administered by the health department, and the number of vaccines shared with community
partners.
Figure 10.01
2009 H1N1 Influenza Summary Report –June 2010, Page 30
Other community partners assisted in the vaccination of the Winnebago County
population, such as hospital systems, pharmacies and private providers. Below, in Figures
10.02 and 10.03, is the distribution of vaccine received and vaccine administered by provider
type. Overall, 116,000 vaccines were received and 57,023 (49.15%) were administered.
When the vaccine began to arrive at the Winnebago County Health Department, the
CDC designated prioritization of vaccine delivery to high risk groups. Those under the age of
24, pregnant women and those aged 25-59 with any of the following conditions; asthma,
COPD, heart disease and diabetes were considered high risk (9). Clinics were set up at various
areas to target these populations, in addition to clinics that visited county schools and daycare
centers. Overall, just over 36,000 vaccines were administered to children in local schools
(37.6% of overall enrollment). In those aged six months to nine years, two doses of the
Figure 10.02
Figure 10.03
2009 H1N1 Influenza Summary Report –June 2010, Page 31
vaccine were required. Of those children in that group who received the first shot, 86%
completed the series. Similar results were seen in daycares, with 2,020 vaccinations
administered (36.9% of overall enrollment), and 74% completing the two-dose series. These
numbers may be lower than the actual outcome as many parents elected to attend one of the
community clinics in lieu of the school vaccination program.
Overall, the WCHD delivered 246 clinics to area schools, daycares, community
appointment clinics and other private enterprise clinics. Through these clinics, over 46,000
vaccine doses were administered. This value includes second doses for those who required the
second dose. Figure 10.04 goes in to more detail about the type of clinic delivered to selected
groups.
Clinic Type Number of Clinics Vaccines Administered
Schools* 123 34,185
Daycares 26 2,020
Community
Appointments 70 8,721
Other (Worksite,
private, etc.) 27 1,201
TOTAL 246 46,127◘
Figure 10.04 *includes second-dose clinics ◘includes second doses
2009 H1N1 Influenza Summary Report –June 2010, Page 32
Figure 10.05
Figure 10.05 shows the number of confirmed H1N1 cases compared to dates to when
vaccine supplies were available in the County. Vaccine did not arrive until week 41, and high
enough amounts to begin mass-vaccination clinics were not received until week 46. This was
similar to the trend in other areas in the country due to issues in the manufacturing of the
vaccine and late distribution as a result.
2009 H1N1 Influenza Summary Report –June 2010, Page 33
XII. Media Coverage
When the first confirmed cases of H1N1 were confirmed, the Winnebago County Health
Department Media division began generating news releases, conducting interviews with local
television and newspaper, holding press conferences, giving presentations and administering
Public Service Announcements and commercials for radio and television. In total, there were
over 1,600 media impressions from April 2009 to February 2010. In addition, signs were
placed at both the Cherry Vale Mall and at the Chicago-Rockford International Airport. Signs
and handouts were also made available at the entrances of all health facilities within the
County. The below figure (12.01) shows the number of selected media inquiries by week with
an overlay of confirmed H1N1 cases.
There were significant associations between confirmed H1N1 cases and presentations
given and television media impressions. There were also numerous radio advertisements, both
paid and free PSA‘s.
Figure 12.01
2009 H1N1 Influenza Summary Report –June 2010, Page 34
Figure 12.02, below, shows the number of cumulative radio impressions. There were both paid
advertisements and free Public Service Announcements (PSA‘s) that were delivered on
numerous radio stations, beginning in week 45.
Figure 12.02
The use of social media networks, such as Facebook, Twitter and website updates were
also frequently utilized throughout the duration of the pandemic. Before the pandemic began,
the website was averaging 800 visits a week, but during the first wave, those visits increased to
over 1,800 visits a week. During the second wave, the weekly average remained high, at just
over 1,900 visits. There was a direct association between website visits and Emergency
Department visits (Figure 12.03), website hits and a confirmed H1N1 case (Figure 12.04), and
website hits and overall media impressions (Figure 12.05).
2009 H1N1 Influenza Summary Report –June 2010, Page 35
Figure 12.03
Figure 12.04
2009 H1N1 Influenza Summary Report –June 2010, Page 36
Figure 12.05
During the first wave and latent period of the H1N1 pandemic, the majority of media
coverage was designed around the three C‘s (Cover, Clean, Contain) and other preventative
measures to limit the number of H1N1 cases. Once vaccine became available, the coverage
began to shift to begin the mass vaccination campaign. From October 18, 2009 to February 27,
2010, there were a combined 32,109 impressions, including website hits and advertisements.
This was also the time when new signs were placed at Cherry Vale Mall and the Chicago-
Rockford International airport, along with on Rockford Mass Transit District buses. In Figure
12.06, below, the association between the media push and increased vaccination amounts
(r-score, 0.969) is visible.
Figure 12.06
2009 H1N1 Influenza Summary Report –June 2010, Page 37
XIII. Discussion
From April 26, 2009 to February 27, 2010, Winnebago County experienced 234
H1N1 related illnesses, 161 H1N1 related hospitalizations and five H1N1 related deaths.
Surveillance activities through sentinel reports, laboratory confirmations, school absenteeism
reporting and influenza-like illness reporting made monitoring the trends of H1N1 more
streamlined than if they were not available.
Through ILI monitoring, trends of sickness were visible, both within the County and
region-wide. Locally, there were large increases in activity in those under the age of 18, with
data peaking between Weeks 42 (0-4 ILI, 29.1% of total visits) and 43 (5-17 ILI, 34.9% of total
visits). This data mirrors the large increases in school absenteeism data.
Jurisdictionally, Winnebago County saw increased levels of ILI activity compared to
much of the Chicago region, with the exception of Kane County (see Figure 5.03, page 8). The
peak of ILI activity occurred at the same time for all 5 comparative jurisdictions (Week 43).
Overall, the higher rate of cases were in the younger populations at the beginning of the
pandemic, but as the pandemic progressed, those who were older were at more risk to develop
complications. This data mirrors both state and national trends. For hospitalized cases, more
were 18 years and over, rather than under the age of 18. That trend is reflected in the rate per
100,000 population (see Figure 6.01, page 19).
While the higher number of cases was in those under 18 years old, 93% of all cases over
the age of 45 were hospitalized (see Figure 7.01, page 23). This is due in part to the higher
number of co-morbidities, such as asthma and diabetes, present in the older populations.
Overall, 69% of all cases were hospitalized, but after July 24, only hospitalized cases for ILI
and suspect cases from select sentinel sites were tested for H1N1.
Projection extrapolation and analysis was a very useful tool to analyze the possible
spread of H1N1 across a jurisdiction, since most cases may seek medical care or be tested for
H1N1. Overall, the projected H1N1 impact in Winnebago County from April to December 12,
2009 is 32,110 cases per 100,000 population (96,412 median projected cases). This figure is
177% higher than the Illinois rate (11,595 per 100,000) and is 78% the National Average
(17,923 per 100,000). It is believed that higher hospitalization rates and greater access to care
may have an impact on the large increases in rate.
Providing vaccine to all community members was a large focus of the Winnebago
County Health Department. In forming a public-private partnership, over 57,000 vaccinations
2009 H1N1 Influenza Summary Report –June 2010, Page 38
were administered (as of February 27, 2010). Clinics were provided by the Health Department,
private physicians and medical centers, in addition to various private workplaces and
pharmacies. Vaccination clinics were largely driven by media coverage that was designed to
spread the word about vaccinations. The high r-score (0.969) demonstrates that the media
impressions and website usage were helpful in encouraging people to get vaccinations.
There were various strengths to the Winnebago County H1N1 response. Previous
pandemic influenza plans aided in the preparation for the 2009 H1N1 pandemic, as well as
opening the communication channels with partner agencies around the County. Cooperation
from these partners allowed resources to be utilized in the best possible way, maximizing the
H1N1 response. New methods to reach the community, such as the health department
webpage, Facebook and Twitter proved effective in generating an appropriate response to either
prevention of H1N1 or vaccination for H1N1.
There were also limitations discovered during the H1N1 pandemic period. First, the
pandemic was widespread when it was recognized in the population, and differentiation
between H1N1 and seasonal influenza proved a challenge, particularly early in the pandemic
(April, May and June). Vaccine production technology is aged, but capacity was expanded to
meet increased demand. Finally, due to grant funding limitations, surge capacity, most notably
at local Emergency Departments, was severely challenged.
Lessons learned from the 2009 H1N1 pandemic are essentially important in the
improvement of local pandemic bioagent and all-hazards response plans. Currently, planning
exercises are being developed using lessons learned from the 2009 H1N1 pandemic.
Surveillance methods are being streamlined and made more effective to monitor both H1N1 and
seasonal influenza, but other potential bioagents in the community.
In conclusion, the efforts asserted by the Winnebago County Health Department and its
community partners were beneficial in reducing the impact of the 2009 H1N1 influenza
pandemic. Surveillance efforts are still currently monitoring the state of the 2009 H1N1
influenza within the county, and vaccination clinics are still being held. This report will
continue to be updated as data becomes available.
2009 H1N1 Influenza Summary Report –June 2010, Page 39
XIV. Acknowledgments
It must be recognized that a great deal of compilation and analysis of data was necessary
to develop this report. Its‘ principal author is Zachary McCormic, Epidemiologist for the
Winnebago County Department of Public Health. This report was reviewed and critiqued by
Kara McCluskey, Communicable Disease Supervisor and Dee Dunnett, Health Promotion and
Protection Center Director, as well as by Administration, prior to its posting.
The Winnebago County Department of Public Health also wishes to recognize each of
our staff for their flexibility and contribution for protecting the health of Rockford and
Winnebago County residents during the 2009-2010 H1N1 Influenza Pandemic. Their
willingness to cover the routine responsibilities of others or to be directly involved in the
prolonged and intense pandemic response was fundamental to our Department‘s ability to cope
with this rare public health threat.
The Winnebago County Department of Public Health would like to thank all the public
and private community partners, consortium members and volunteers who during this past year
provided exemplary services so essential to protecting the health of this Community over the
course of this Pandemic. Collectively these efforts have led to achieving the pandemic response
strategic goals to 1.) limit death and suffering through proper preventive, curative and
supportive care to those most vulnerable, 2.) aid in the application of the least restrictive
interventions to contain the disease threat and 3.) contribute to the economic and financial
stability of the community during a pandemic that infected almost estimated one-third of our
community‘s residents.
Our appreciation must be expressed to that of the local popular media including
newspapers, television stations and radio stations for their support of the key messages so
essential to keeping the public accurately informed. And finally, the general public must be
recognized for their adherence to the recommendations provided and for their understanding
and patience in accessing educational and vaccination services throughout the course of this
Pandemic. Public Health is often defined as what we do collectively to assure conditions in
which our residents can be healthy. The 2009-2010 H1N1 Influenza Pandemic response
exemplifies the spirit of our community‘s commitment to public health practices and principles.
2009 H1N1 Influenza Summary Report –June 2010, Page 40
XV. Works Cited
1. CDC. (2009). Swine influenza a (H1N1) infection in two children---southern California,
March--April 2009. MMWR 2009, 58. Retrieved from http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm58d0421a1.htm
2. CDC. (2009). Update: infections with a swine-origin influenza a (H1N1) virus---United
States and other countries, April 28, 2009. MMWR 2009, 58(16), Retrieved from http://
www.cdc.gov/mmwr/preview/mmwrhtml/mm5816a5.htm
3. Centers for Disease Control and Prevention. (2009, October 27). 2009 H1N1 early outbreak
and disease characteristics. Retrieved from http://www.cdc.gov/hin1flu/surveillanceqa.htm
4. CDC. (2009). 2009 Pandemic influenza a (H1N1) virus infections---Chicago, Illinois, April
--July 2009. MMWR 2009, 58(33), Retrieved from http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm5833a1.htm
5. Kinnikinnick schools to reopen. (2009, May 6). Rockford Register Star.
6. Westphal, M. (2009, October 29). South Beloit cancels classes today. Rockford Register
Star.
7. Reed, C., Angulo, F.J., Swerdlow, D.L., Lipsitch, M., Meltze, M.I., Jernigan, D., et al.
Estimates of the prevalence of pandemic (H1N1) 2009, United States, April-July 2009.
Emerg Infect Dis [serial on the internet]. 2009 Dec; [Epub ahead of print]
8. Centers for Disease Control and Prevention. (2010, February 5). Facts about the 2009
H1N1 vaccine. Retrieved from http://www.cdc.gov/h1n1flu/vaccination/
vaccine_keyfacts.htm
9. Centers for Disease Control and Prevention. (2009, November 10). People at high risk of
developing flu-related complications. Retrieved from http://www.cdc.gov/h1n1flu/
highrisk.htm
2009 H1N1 Influenza Summary Report –June 2010, Page 41
XVI. Additional Tables
A. Appendix A
Page - 42
B. Appendix B
Page - 52
C. Appendix C
Page - 59
D. Appendix D
Page - 66
2009 H1N1 Influenza Summary Report –June 2010, Page 42
Appendix A—Influenza-Like Illness*
*-All data analyzed via ESSENCE (Electronic Surveillance System for the Early Notification of Community‐based Epidemics)
Section 1: ILI Activity by Age
Winnebago County versus Regional data, by age
Please note, increases in ILI
activity from weeks 1 through 8
of 2010 are attributable to high
levels of RSV, not H1N1.
2009 H1N1 Influenza Summary Report –June 2010, Page 43
Winnebago County versus other Jurisdiction data, by age
Winnebago County versus Regional data, by age, continued
2009 H1N1 Influenza Summary Report –June 2010, Page 44
Section 2: ILI Activity by Period
Winnebago County versus other Jurisdiction data, by period
Winnebago County versus other Jurisdiction data, by age, continued
2009 H1N1 Influenza Summary Report –June 2010, Page 45
Winnebago County versus other Jurisdiction data, by period, continued
Please note, increases in ILI
activity from weeks 1 through 8 of
2010 are attributable to high levels
of RSV, not H1N1.
2009 H1N1 Influenza Summary Report –June 2010, Page 46
Section 3: ILI Activity by Wave
Wave 1: April 21-June 6, 2009
2009 H1N1 Influenza Summary Report –June 2010, Page 47
Wave 1: April 21-June 6, 2009, continued
Latent Period: June 6-August 29, 2009
2009 H1N1 Influenza Summary Report –June 2010, Page 48
Latent Period: June 6-August 29, 2009, continued
Wave 2: August 30-December 12, 2009
2009 H1N1 Influenza Summary Report –June 2010, Page 49
Wave 2: August 30-December 12, 2009, continued
2009 H1N1 Influenza Summary Report –June 2010, Page 50
Post-Wave Period: December 13, 2009-February 27, 2010
Please note, increases in ILI
activity from weeks 1 through 8 of
2010 are attributable to high levels
of RSV, and not H1N1.
2009 H1N1 Influenza Summary Report –June 2010, Page 51
Post-Wave Period: December 13, 2009-February 27, 2010, continued
2009 H1N1 Influenza Summary Report –June 2010, Page 52
Appendix B: Confirmed H1N1 Cases
Section 1: Wave 1 - April 21-June 6, 2009
Figure B.1.01, above. Dispersal of H1N1 cases by age
for Wave 1. The majority of cases are in those
aged 17 and under.
Figure B.1.02, right. Age range
for all confirmed H1N1 cases
during the first wave period.
Included are case counts and
percentage of overall cases per
age group.
* - Rate per 100,000 population
Age Range Total Cases Rate*
0 - 4 9 / 17% 43.67
5 - 17 27 / 52% 49.94
18 - 44 9 / 17% 8.17
45 - 64 7 / 14% 9.20
65 + 0 / 0% 0
Total 52 / 100% 17.31
Age
Range 2 mo - 61 yrs
Mean 17.22 yrs
Median 10.5 yrs
Figure B.1.04, right. The slight
majority of cases were female
(54%) during the first wave.
Figure B.1.03, left. Age range,
mean and median of all Wave 1
cases.
Gender N %
Female 28 54%
Male 24 46%
2009 H1N1 Influenza Summary Report –June 2010, Page 53
Race
Total Cases
n / % Rate*
White 37 / 71% 14.46
African American/ Black 15 / 29% 41.26
Other 0 / 0% 0
Total 52 / 100% 17.31
Figure B.1.05, left. Racial
distribution of all Wave 1 H1N1
cases. The majority identified
themselves as White.
* - Rate per 100,000
Ethnicity Total Cases n / % Rate*
Hispanic 17 / 45.9% 54.71
Non-Hispanic White 20 / 54.1% 8.90
Total 37 / 100% 14.46
Figure B.1.06, above, shows the ethnic background of
all cases. A slight majority of cases were Non-Hispanic.
* - Rate per 100,000 population
- 0.00
- 1 - 7
- 7.1– 10
- 10.1 - 15
- 15.1 - 20
- 20.1 - 27
- 27+
Figure B.1.07, above, shows the geographical distribution by zip code of the H1N1 cases during
Wave 1. Rates are given per 100,000 population.
2009 H1N1 Influenza Summary Report –June 2010, Page 54
Section 2: Latent Period - June 7-August 29, 2009
Figure B.2.01, above. Dispersal of H1N1 cases by age
for the Latent Period. The majority of cases are in
those aged 17 and under.
Age Range Total Cases n / % Rate*
0 - 4 5 / 50% 24.27
5 - 17 1 / 10% 1.85
18 - 44 3 / 30% 2.72
45 - 64 1 / 10% 1.31
65 + 0 / 0% 0
Total 10 / 100% 3.33
Age Range 2 mo - 54 yrs
Mean 14.07 yrs
Median 8.0 yrs
Gender N %
Female 6 60%
Male 4 40%
Figure B.2.02, above. Age range for
all confirmed H1N1 cases during the
latent period. Included are case
counts and percentage of overall
cases per age group.
* - Rate per 100,000
Figure B.2.03, above. Age range,
mean and median of all latent
period cases.
Figure B.2.04, left. The slight
majority of cases were female
(60%) during the latent period.
2009 H1N1 Influenza Summary Report –June 2010, Page 55
Race
Total Cases
n / % Rate*
White 5 / 50% 1.95
African American/ Black 4 / 40% 11.00
Other 1 / 10% 12.39
Total 10 / 100% 3.33
Ethnicity Total Cases n / % Rate*
Hispanic 0 / 0% 0.00
Non-Hispanic White 5 / 100% 2.22
Total 5 / 100% 1.95
Figure B.2.05, left.
Racial distribution of
all Wave 1 H1N1
cases. The majority
identified themselves
as White.
* - Rate per 100,000
Figure B.2.06, above, shows the ethnic
background of all cases. All cases were
reported as Non-Hispanic.
* - Rate per 100,000
Figure B.2.07, above, shows the geographical distribution by zip code of the H1N1 cases during
Wave 1. Rates are given per 100,000 population.
- 0.00
- 1 - 4.5
- 4.6 - 5.5
- 5.6 - 6.8
- 6.9 - 7.4
- 7.5 - 8.3
- 8.4 +
2009 H1N1 Influenza Summary Report –June 2010, Page 56
Section 3: Wave 2 - August 30-December 12, 2009
Figure B.3.01, above. Dispersal of H1N1 cases by age
for Wave 2. The majority of cases are in those
over the age of 18.
Figure B.3.02, above. Age range for
all confirmed H1N1 cases during the
second wave period. Included are
case counts and percentage of overall
cases per age group.
* - Rate per 100,000 population
Figure B.3.03, below. Age range,
mean and median of all Wave 2
cases.
Figure B.3.04, right. The slight
majority of cases were female
(55%) during the second wave.
Age Range Total Cases n / % Rate*
0 - 4 31 / 18% 150.52
5 - 17 34 / 20% 62.92
18 - 44 41 / 24% 37.24
45 - 64 47 / 27% 61.79
65 + 18 / 11% 45.66
Total 171 / 100% 56.96
Age Range 1 mo - 85 yrs
Mean 31.68 yrs
Median 28.0 yrs
Gender N %
Female 94 55%
Male 77 45%
2009 H1N1 Influenza Summary Report –June 2010, Page 57
Figure B.3.05, left.
Racial distribution of
all Wave 2 H1N1
cases. The majority
identified
themselves as White.
* - Rate per 100,000
population
Figure B.3.06, right, shows the ethnic background of
all cases. The majority of cases were Non-Hispanic.
* - Rate per 100,000 population
Race Total Cases n / % Rate*
White 109 / 64% 42.61
African American/ Black 45 / 26% 123.84
Other 17 / 10% 210.60
Total 171 / 100% 56.96
Ethnicity Total Cases n / % Rate*
Hispanic 24 / 28.2% 77.28
Non-Hispanic White 85 / 71.8% 37.82
Total 109 / 100% 42.61
- 0.00
- 1 - 30
- 30.1 - 47
- 47.1 - 55
- 55.1 - 70
- 70.1 - 105
- 105.1 +
Figure B.3.07, above, shows the geographical distribution by zip code of the H1N1 cases during
Wave 2. Rates are given per 100,000 population
2009 H1N1 Influenza Summary Report –June 2010, Page 58
Section 4: Post-Wave Period - December 13, 2009-February 27, 2010
Due to a significantly reduced number of cases during the post-wave period, data has been
excluded from publication.
2009 H1N1 Influenza Summary Report –June 2010, Page 59
Appendix C: Hospitalized H1N1 Cases
Section 1: Wave 1 - April 21-June 6, 2009
Figure C.1.01, above. Dispersal of H1N1
hospitalizations by age for Wave 1. The majority of
cases are in those aged 17 and under.
Figure C.1.02, above. Age range for all
confirmed H1N1 hospitalizations
during the first wave period. Included
are case counts and percentage of
overall cases per age group.
* - Rate per 100,000 population
Figure C.1.03, below. Age range,
mean and median of all Wave 1
hospitalizations.
Figure C.1.04, left. The
majority of hospitalizations were
male (67%) during the first wave.
Age Range Total Hospitalizations Rate*
0 - 4 2 / 22% 9.70
5 - 17 3 / 34% 5.54
18 - 44 2 / 22% 1.81
45 - 64 2 / 22% 2.62
65 + 0 / 0% 0
Total 9 / 100% 2.99
Age Range 2 mo - 49 yrs
Mean 21.49 yrs
Median 12.0 yrs
Gender N %
Female 3 33%
Male 6 67%
2009 H1N1 Influenza Summary Report –June 2010, Page 60
Figure C.1.05, above. Racial distribution
of all Wave 1 H1N1 hospitalizations. The
majority identified themselves as White.
* - Rate per 100,000 population
Figure C.1.06, below, shows the ethnic
background of all hospitalized cases. The
majority of cases were Non-Hispanic.
* - Rate per 100,000 population
Figure C.1.07, above, shows the geographical distribution by zip code of the H1N1
hospitalizations during Wave 1. Rates are given per 100,000 population.
- 0.00
- 1 - 4
- 4.1 - 4.6
- 4.7 - 4.8
- 4.9 - 5.5
- 5.6 - 6.3
- 6.4 +
Race Total Hospitalizations Rate*
White 5 / 71% 1.95
African American/ Black 4 / 29% 11.00
Other 0 / 0% 0
Total 9 / 100% 2.99
Ethnicity Total Hospitalizations Rate*
Hispanic 2 / 40% 6.43
Non-Hispanic White 3 / 60% 1.33
Total 5 / 100% 1.95
2009 H1N1 Influenza Summary Report –June 2010, Page 61
Section 2: Latent Period - June 7-August 29, 2009
Figure C.2.01, above. Dispersal of H1N1
hospitalizations by age for the Latent Period. The
majority of cases are in those aged 17 and under.
Figure C.2.02, above. Age range for
all confirmed H1N1 hospitalizations
during the latent period. Included
are case counts and percentage of
overall cases per age group.
* - Rate per 100,000 population
Figure C.2.03, below. Age range,
mean and median of all latent
period hospitalizations.
Figure C.2.04, right. The slight
majority of hospitalizations were
male (60%) during the latent
period.
Age Range Total Hospitalizations n / % Rate*
0 - 4 2 / 40% 9.71
5 - 17 0 / 0% 0
18 - 44 2 / 40% 1.82
45 - 64 1 / 20% 1.31
65 + 0 / 0% 0
Total 5 / 100% 1.67
Age Range 6 mo - 54 yrs
Mean 20.9 yrs
Median 22.0 yrs
Gender N %
Female 2 40%
Male 3 60%
2009 H1N1 Influenza Summary Report –June 2010, Page 62
Figure C.2.05, above. Racial distribution
of all Wave 1 H1N1 hospitalizations. The
majority identified themselves as White.
* - Rate per 100,000 population
Figure C.2.06, below, shows the ethnic
background of all hospitalized cases. All
cases were reported as Non-Hispanic.
* - Rate per 100,000 population
Figure C.2.07, above, shows the geographical distribution by zip code of the H1N1
hospitalizations during Wave 1. Rates are given per 100,000 population.
- 0.00
- 1 - 3.7
- 3.8 - 4.8
- 4.9 - 5.9
- 6.0 +
Race Total Hospitalizations Rate*
White 3 / 60% 1.95
African American/ Black 1 / 20% 11.01
Other 1 / 20% 12.38
Total 5 / 100% 3.33
Ethnicity Total Hospitalizations Rate*
Hispanic 0 / 0% 0
Non-Hispanic White 3 / 100% 1.33
Total 3 / 100% 1.17
2009 H1N1 Influenza Summary Report –June 2010, Page 63
Section 3: Wave 2 - August 30-December 12, 2009
Figure C.3.01, above. Dispersal of H1N1
hospitalizations by age for Wave 2. The majority of
cases are in those over the age of 18.
Figure C.3.02, above. Age range
for all confirmed H1N1
hospitalizations during the second
wave period. Included are case
counts and percentage of overall
cases per age group.
* - Rate per 100,000 population
Figure C.3.03, below. Age range,
mean and median of all Wave 2
hospitalizations.
Figure C.3.04, left. The slight
majority of hospitalizations were
female (55%) during the second
Wave period.
Age Range Total Hospitalizations n / % Rate*
0 - 4 23 / 16% 111.62
5 - 17 24 / 17% 44.40
18 - 44 34 / 23% 30.88
45 - 64 47 / 32% 61.78
65 + 18 / 12% 45.67
Total 146 / 100% 48.63
Age Range 1 mo - 85 yrs
Mean 37.83 yrs
Median 39.5 yrs
Gender N %
Female 80 55%
Male 66 45%
2009 H1N1 Influenza Summary Report –June 2010, Page 64
Figure C.3.05, above. Racial distribution
of all Wave 2 H1N1 hospitalizations. The
majority identified themselves as White.
* - Rate per 100,000 population
Figure C.3.06, below, shows the ethnic
background of all hospitalized cases. The
majority of cases were Non-Hispanic.
* - Rate per 100,000 population
Figure C.3.07, above, shows the geographical distribution by zip code of the H1N1
hospitalizations during Wave 2. Rates are given per 100,000 population.
- 0.00
- 1 - 27
- 27.1 - 42
- 42.1 - 56
- 56.1 - 68
- 68.1 - 88
- 88.1 +
Race Total Hospitalizations Rate*
White 98 / 67% 42.61
African American/ Black 35 / 24% 123.85
Other 13 / 9% 210.60
Total 146 / 100% 56.96
Ethnicity Total Hospitalizations Rate*
Hispanic 22 / 22.4% 70.84
Non-Hispanic White 76 / 77.6% 33.82
Total 98 / 100% 38.31
2009 H1N1 Influenza Summary Report –June 2010, Page 65
Section 4: Post-Wave Period - December 13-February 27, 2009
Due to a significantly reduced number of cases during the post-wave period, data has been
excluded from publication.
2009 H1N1 Influenza Summary Report –June 2010, Page 66
Appendix D: Percent of H1N1 Cases Hospitalized
Age Range Total Cases Total Hospitalizations % Hospitalized
0 - 4 9 2 22%
5 - 17 27 3 11%
18 - 44 9 2 22%
45 - 64 7 2 29%
65 + 0 0 --
Total 52 9 17%
Section 1: Wave 1 - April 21-June 6, 2009
Gender Total
Total % Hospitalized
Female 28 3 11%
Male 24 6 25%
Total 52 9 17%
Race Total Cases Total Hospitalizations % Hospitalized
White 37 5 14%
African American/ Black 15 4 27%
Other 0 0 --
Total 52 9 17%
Ethnicity Total Cases
Total
Hospitalizations
% Hospitalized
Hispanic 17 2 12%
Non-Hispanic White 20 3 15%
Total 37 5 14%
Figure D.1.01 - Percent of hospitalizations by age for Wave 1.
Figure D.1.02 - Percent of hospitalizations by gender for Wave 1.
Figure D.1.03 - Percent of hospitalizations by race for Wave 1.
Figure D.1.04 - Percent of hospitalizations by ethnicity for Wave 1.
2009 H1N1 Influenza Summary Report –June 2010, Page 67
Age Range Total Cases Total Hospitalizations % Hospitalized
0 - 4 5 2 40%
5 - 17 1 0 0%
18 - 44 3 2 67%
45 - 64 1 1 100%
65 + 0 0 --
Total 10 5 50%
Gender Total Cases
Total
Hospitalizations
% Hospitalized
Female 6 2 33%
Male 4 3 75%
Total 10 5 50%
Race Total Cases Total Hospitalizations % Hospitalized
White 5 3 60%
African American/ Black 4 1 25%
Other 1 1 100%
Total 10 5 50%
Ethnicity Total Cases
Total
Hospitalizations
% Hospitalized
Hispanic 0 0 --
Non-Hispanic White 5 3 60%
Total 5 3 60%
Section 2: Latent Period - June 7-August 29, 2009
Figure D.2.01 - Percent of hospitalizations by age for the Latent Period.
Figure D.2.02 - Percent of hospitalizations by gender for the Latent Period.
Figure D.2.03 - Percent of hospitalizations by race for the Latent Period.
Figure D.2.04 - Percent of hospitalizations by ethnicity for the Latent Period.
2009 H1N1 Influenza Summary Report –June 2010, Page 68
Section 3: Wave 2 - August 30-December 12, 2009
Age Range Total Cases Total Hospitalizations % Hospitalized
0 - 4 31 23 74%
5 - 17 34 24 71%
18 - 44 41 34 83%
45 - 64 47 47 100%
65 + 18 18 100%
Total 171 146 85%
Due to a significantly reduced number of cases during the post-wave period, data has been
excluded from publication.
Section 4: Post-Wave Period - December 13-February 27, 2009
Gender Total Cases
Total
Hospitalizations
% Hospitalized
Female 94 80 85%
Male 77 66 86%
Total 171 146 85%
Race Total Cases Total Hospitalizations % Hospitalized
White 109 98 90%
African American/ Black 45 35 78%
Other 17 13 76%
Total 171 146 85%
Ethnicity Total Cases
Total
Hospitalizations
% Hospitalized
Hispanic 24 22 92%
Non-Hispanic 85 76 89%
Total 109 98 90%
Figure D.3.01 - Percent of hospitalizations by age for Wave 2.
Figure D.3.02 - Percent of hospitalizations by gender for Wave 2.
Figure D.3.03 - Percent of hospitalizations by race for Wave 2.
Figure D.3.04 - Percent of hospitalizations by ethnicity for Wave 2.
2009 H1N1 Influenza Summary Report –June 2010, Page 69
This has been a publication of the Winnebago County Health Department
401 Division Street
Rockford, IL 61104
(815) 720-4000
www.wchd.org