2009 H1N1 Mid-Term Review - WCHD H1N1 Influenza Pandemic... · 2015. 1. 6. · strain of the...

2009 H1N1 Influenza Summary Report –June 2010,

2009 H1N1 Mid-Term Review Winnebago County, Illinois

April 2009-February 2010

A Publication of the Winnebago County Health Department, June 2010.


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


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.


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.


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.


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.


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.


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


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


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.


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.


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


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.


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.


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


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


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


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.


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.


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%


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


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


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


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.


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


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.


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.


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 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.


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


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


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


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


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.


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


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).


Figure 12.03

Figure 12.04


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


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


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.


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.


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


XVI. Additional Tables

A. Appendix A

Page - 42

B. Appendix B

Page - 52

C. Appendix C

Page - 59

D. Appendix D

Page - 66


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.


Winnebago County versus other Jurisdiction data, by age

Winnebago County versus Regional data, by age, continued


Section 2: ILI Activity by Period

Winnebago County versus other Jurisdiction data, by period

Winnebago County versus other Jurisdiction data, by age, continued


Winnebago County versus other Jurisdiction data, by period, continued


activity from weeks 1 through 8 of

2010 are attributable to high levels

of RSV, not H1N1.


Section 3: ILI Activity by Wave

Wave 1: April 21-June 6, 2009


Wave 1: April 21-June 6, 2009, continued

Latent Period: June 6-August 29, 2009


Latent Period: June 6-August 29, 2009, continued

Wave 2: August 30-December 12, 2009


Wave 2: August 30-December 12, 2009, continued


Post-Wave Period: December 13, 2009-February 27, 2010


activity from weeks 1 through 8 of

2010 are attributable to high levels

of RSV, and not H1N1.


Post-Wave Period: December 13, 2009-February 27, 2010, continued


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%


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


Hispanic 17 / 45.9% 54.71


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.


- 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.


Section 2: Latent Period - June 7-August 29, 2009


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


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


(60%) during the latent period.


Race

Total Cases

n / % Rate*

White 5 / 50% 1.95


Other 1 / 10% 12.39

Total 10 / 100% 3.33


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


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 +


Section 3: Wave 2 - August 30-December 12, 2009


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



Figure B.3.03, below. Age range,


cases.

Figure B.3.04, right. The slight


(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


Mean 31.68 yrs

Median 28.0 yrs

Gender N %

Female 94 55%

Male 77 45%


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.


Race Total Cases n / % Rate*

White 109 / 64% 42.61


Other 17 / 10% 210.60

Total 171 / 100% 56.96


Hispanic 24 / 28.2% 77.28


Total 109 / 100% 42.61

- 0.00

- 1 - 30

- 30.1 - 47

- 47.1 - 55

- 55.1 - 70

- 70.1 - 105

- 105.1 +


Wave 2. Rates are given per 100,000 population


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.


Appendix C: Hospitalized H1N1 Cases


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.


Figure C.1.03, below. Age range,


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


Mean 21.49 yrs

Median 12.0 yrs

Gender N %

Female 3 33%

Male 6 67%


Figure C.1.05, above. Racial distribution

of all Wave 1 H1N1 hospitalizations. The

majority identified themselves as White.


Figure C.1.06, below, shows the ethnic

background of all hospitalized cases. The

majority of cases were Non-Hispanic.


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


Other 0 / 0% 0

Total 9 / 100% 2.99

Ethnicity Total Hospitalizations Rate*

Hispanic 2 / 40% 6.43


Total 5 / 100% 1.95




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.



mean and median of all latent

period hospitalizations.

Figure C.2.04, right. The slight


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


Mean 20.9 yrs

Median 22.0 yrs

Gender N %

Female 2 40%

Male 3 60%







background of all hospitalized cases. All

cases were reported as Non-Hispanic.




- 0.00

- 1 - 3.7

- 3.8 - 4.8

- 4.9 - 5.9

- 6.0 +


White 3 / 60% 1.95


Other 1 / 20% 12.38

Total 5 / 100% 3.33


Hispanic 0 / 0% 0


Total 3 / 100% 1.17




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





hospitalizations.

Figure C.3.04, left. The slight


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


Mean 37.83 yrs

Median 39.5 yrs

Gender N %

Female 80 55%

Male 66 45%







background of all hospitalized cases. The

majority of cases were Non-Hispanic.




- 0.00

- 1 - 27

- 27.1 - 42

- 42.1 - 56

- 56.1 - 68

- 68.1 - 88

- 88.1 +


White 98 / 67% 42.61


Other 13 / 9% 210.60

Total 146 / 100% 56.96


Hispanic 22 / 22.4% 70.84


Total 98 / 100% 38.31


Section 4: Post-Wave Period - December 13-February 27, 2009




Appendix D: Percent of H1N1 Cases 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%


Gender Total

Total % Hospitalized

Female 28 3 11%

Male 24 6 25%

Total 52 9 17%


White 37 5 14%


Other 0 0 --

Total 52 9 17%

Ethnicity Total Cases

Total

Hospitalizations

% Hospitalized

Hispanic 17 2 12%


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.



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%


White 5 3 60%


Other 1 1 100%

Total 10 5 50%


Total

Hospitalizations

% Hospitalized

Hispanic 0 0 --


Total 5 3 60%


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.




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%



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%


White 109 98 90%


Other 17 13 76%

Total 171 146 85%


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.


This has been a publication of the Winnebago County Health Department

401 Division Street

Rockford, IL 61104

(815) 720-4000

www.wchd.org

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