Research Method Literature Review

Original Research

Impact of School Flu Vaccine Program on Student Absences

Sara S. Plaspohl, DrPH, CHES1, Betty T. Dixon, DrPH, RN2, James A. Streater, EdD, CHES1, Elizabeth T. Hausauer, MSN, RN2, Christopher P. Newman, MPH

1 , and Robert L. Vogel, PhD

3

Abstract

Literature provides evidence that school attendance correlates with academic performance and student success. Influenza is a contributing factor to school absences. Primary prevention for influenza includes immunization. School-located influenza vaccine (SLIV) programs provide greater access for students to be immunized. A retrospective review of preexisting data from four academic years was conducted to examine the relationship between SLIV participation and absenteeism among students at eight public elementary schools in Effingham County, Georgia. Results identified differences in average frequency of absences between SLIV and non-SLIV years as well as between SLIV participants and nonparticipants for the 2 SLIV years. Implications for practice include the potential for increased herd immunity among students, which may also extend to other parties within the school community and at home, thus promoting overall wellness and future student success.

Keywords

immunizations, school-based clinics, collaboration/multidisciplinary teams, academic achievement/attendance, health/wellness, elementary, quantitative research

Introduction

Scientific literature indicates school absenteeism correlates

with lower standardized test scores and dropout rates

(Balfanz & Byrnes, 2012). Missing even a few days of

school, regardless of cause, can impact student academic

performance, shape attitudes about school, and affect school

dropout rates (Chang & Romero, 2008; U.S. Department of

Education, 2009). McGiboney (2012) examined attendance

data among Georgia elementary school students, noting a

significant relationship between number of days in school

(defined as ‘‘seat time’’), success in school, and ultimately,

probability of high school graduation.

One cause of school absenteeism is influenza. The effects

of influenza are widespread. The virus possesses the capabil-

ity to infect large number of people rapidly, impacting 10%– 20% of the U.S. population every year (Weycker et al., 2005). Those who become infected develop symptoms that

can last several days, leading to bed rest, school/work loss,

and increased physician visits. Mortality rates due to influ-

enza infection have been estimated to exceed 36,000 each

year, and the annual economic impact of influenza in the

United States has been estimated between $11 and $18

billion dollars (Davis, King, Moag, Cummings, & Magder,

2008). Infection rates among children are the highest among

any age group during a typical influenza season, averaging

25%–43% (Weycker et al., 2005). When children are sick

with the flu, they miss school, and as indicated earlier, this

can have a negative impact on their overall academic

success.

An increased understanding of the impact of influenza on

school-aged children prompted the Centers for Disease Con-

trol, the American Academy of Pediatrics, and the American

Academy of Family Practitioners to recommend in 2008 that

all children aged 6 months through 18 years be immunized

every year against influenza (Centers for Disease Control,

2010). Vaccinations against influenza have been demon-

strated to substantially lower the cases of influenza and

mitigate its dissemination throughout populations (Reichert

et al., 2001). Japan utilized vaccination of school children

after mass influenza infection of its population led to exten-

sive school closures (Reichert et al., 2001). Due to the

increased risk of children carrying and disseminating influ-

enza to the population, policy initiatives required the vacci-

nation of all Japanese school children to allay the disease. As

1 Armstrong Atlantic State University, Savannah, GA, USA 2 Coastal Health District, Savannah, GA, USA 3

Georgia Southern University, Statesboro, GA, USA

Corresponding Author:

Sara S. Plaspohl, DrPH, CHES, Armstrong Atlantic State University, 11935

Abercorn Street, Solms Hall 201J, Savannah, GA 31419, USA.

Email: [email protected]

The Journal of School Nursing 2014, Vol. 30(1) 75-80 ª The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1059840513487750 jsn.sagepub.com

a result of this program, flu-related mortality rates decreased

dramatically, supporting conclusions that vaccine-induced

herd immunity contributed to Japan’s average life span,

which was the highest in the world (Reichert et al., 2001).

School-located influenza vaccination (SLIV) programs

provide a valuable primary prevention measure via the

administration of influenza vaccine by public health depart-

ment and school nurses to students within the school setting.

SLIV programs offer an opportunity to vaccinate school

children while at school, thus lessening the proliferation of

influenza. SLIV programs are efficient in providing access

for immunization to large numbers of children, are cost

effective when compared to immunizing children in physi-

cian offices and clinics, and reduce the indirect costs of

vaccination for parents by decreasing the need for their time

and work absence to have their child immunized (King et al.,

2006; Szilagyi, Iwane, & Humiston, 2003; White, Lavoie &

Nettleman, 1999). As noted earlier, the time lost by a student

from school due to illness can result in missed learning

opportunities (White, Lavoie, & Nettleman, 1999). SLIV

programs also serve an important role in lowering the

amount of time parents spend caring for sick children and

lowering the absenteeism rates for school children. SLIV

programs can help reduce the workload burden of primary

care providers and increase the overall vaccination rates

among school children (Schieber, Kennedy, & Kahn, 2012).

SLIV programs are available in some Georgia school dis-

tricts, including Effingham County, where an SLIV program

has been in effect since the 2010–2011 academic school

year. To date, there has been little research to explore the

correlation between student participation in SLIV programs

and school absenteeism (Hull & Ambrose, 2011). The

purpose of this research was to assess the relationship of a

local SLIV program in reducing student absences and thus

increasing seat time in class for elementary school students

in Effingham County, Georgia.

Method

A review of retrospective data from two sources was con-

ducted to answer two research questions: (1) Was there a

difference in average absenteeism among elementary school

students for 2 years of pre-SLIV compared to 2 years with

SLIV? (2) For the 2 years with SLIV, was there a difference

in average absenteeism between elementary school students

who were vaccinated in the SLIV program and those who

were not vaccinated in the SLIV program?

Study subjects included all elementary-grade students

(K-5) enrolled in the eight public schools within Effingham

County during four academic years, with the first 2 years

(2007–2008 and 2008–2009) designated as ‘‘pre-SLIV’’

years because the SLIV program was not yet in place, and

the last two (2010–2011 and 2011–2012) designated as

‘‘SLIV’’ years because the SLIV program was in place. One

academic year (2009–2010) between the pre-SLIV and

SLIV years was excluded from the study at the recommen-

dation of the Coastal Health District Nursing Director, as

that particular year was considered an anomaly because of

the administration of greater than normal influenza vaccina-

tions among the entire population due to the prevalence of

the H1N1 virus.

During early planning, the research team met with the

Superintendent of the Effingham County Board of Educa-

tion (BOE) to obtain his support for the study. The study was

approved by the Armstrong Atlantic State University Institu-

tional Review Board prior to the start of data collection. In

May 2012, a formal request was then delivered to the Effing-

ham County BOE for the first data source that included a

series of data for the 4 years to be studied (2 pre-SLIV and

2 SLIV). Each year of data included basic demographic vari-

ables of school, grade, gender, and race as well as a number

of excused and unexcused school absences for 80 seat days

(days in school) after students returned to school in January

after the holiday break. An absence was defined as any day

when a student was out of school for more than half day for

any reason, in keeping with the BOE’s definition of the

occurrence. Absences were further categorized as being

excused if the student either brought a note from home

(e.g., doctor’s excuse for illness) or was out for a school-

related activity (e.g., athletic event or band concert), while

unexcused absences were those for which the student did not

bring a note. It was possible that unexcused absences could

include influenza-related illness or other types of excusable

reasons for instances where a note was not presented; there-

fore, for purposes of the study, all excused and unexcused

absences were summarized into an aggregate category of

total absences per student without distinguishing the

circumstances.

The second source of data was provided by the Effingham

County Health Department in May 2012 and consisted of the

consent forms presented by students at the time of receiving

their immunization for the SLIV program. A dichotomous

variable was created to indicate whether or not each student

was immunized with either nasal-spray flu vaccine or flu

shot in the SLIV program during the 2 years of administra-

tion. All vaccinated students were then matched to their

individual attendance information with a ‘‘yes,’’ while all

students who did not receive an immunization at school were

categorized as ‘‘no’’ for SLIV participation.

The quantitative data were analyzed in three phases with

SAS1 9.3 STAT (SAS Instititue, Inc., Cary, North Carolina).

For discussion purposes, the following labels identify each

group within the analysis: ‘‘Group A’’ refers to the aggregate

of students in the 2 pre-SLIV years (2007–2008 and 2008–

2009); ‘‘Group B’’ refers to the aggregate of students in the

2 SLIV years (2010–2011 and 2011–2012); ‘‘Group B-V’’

refers to the aggregate of students in Group B who were

vaccinated in the SLIV program; ‘‘Group B-U’’ refers to the

aggregate of students in Group B who were not vaccinated in

the SLIV program.

76 The Journal of School Nursing 30(1)

In the first phase of analysis, descriptive statistics were

generated for demographic variables to obtain a profile of

study subjects, including gender, race, average number of

days absent per student for each of the 4 years, and SLIV

vaccination within the 2 SLIV years. In phase two, indepen-

dent t tests were performed to analyze the difference in the

overall mean absences between Group A and Group B. In

phase three, independent t tests were performed to analyze

the difference in the overall mean absences between Group

B-V and Group B-U. Statistical models were used to evalu-

ate independent effects; all tests used a � .05 as the level of significance.

Results

The study population for each of the four academic years

was consistent in quantity, ranging from 4,674 to 5,201 for

the 2 pre-SLIV years and 4,797 to 4,799 for the 2 SLIV

years. Gender distribution was evenly split for the students,

with slightly more than half (52%) being male and the remaining 48% being female. Using BOE categories for self-disclosed race, the student population included 77% White non-Hispanic, 14% Black, 4% Hispanic, 4% multira- cial, 1% Asian/Pacific Islander, and <1% American Indian/ Alaska Native or unknown. For the 2 SLIV years, 940 (20%) students participated in the vaccination program in the first

year of implementation (2010–2011), and 1,230 (26%) par- ticipated in the second year (2011–2012), reflecting a 30% increase in the participation rate. Refer to Table 1 for sum-

mary of findings. All the students were absent for an average

of 2.4 days for 2007–2008 and 2.7 days for 2008–2009,

increasing to 3.2 average days missed for 2010–2011 and

then 2.6 average days for final year 2011–2012 (Figure 1).

For the 2 SLIV years, the average number of absences was

2.7 days for students who received SLIV vaccination in

2010–2011, decreasing to 2.2 days for 2011–2012; likewise,

the average number of absences for students not vaccinated

in the SLIV program during those years was 3.3 and 2.8

days, respectively (Figure 2).

In order to test the first research question of whether there

was a difference in the overall mean absences between the 2

pre-SLIV years (2007–2008 and 2008–2009) and the 2 SLIV

years (2010–2011 and 2011–2012), an independent t test

compared aggregate absenteeism for Group A (2.53 days)

and Group B (2.89 days), yielding a statistically significant

difference of 0.36 days (p < .0001; 95% confidence interval [CI] ¼ [0.28, 0.44]). To further explore these groups of inter- est, two additional independent t tests were conducted. The

first test compared the overall mean absenteeism for Group

A (2.53 days) and Group B-V (2.39 days), yielding a statis-

tically significant difference of .14 (p < .0001, 95% CI ¼ [0.02, 0.26]). The second test compared the overall mean

absenteeism of Group A (2.53 days) and Group B-U (3.03

days), yielding a statistically significant difference of .50

(p < .0001, 95% CI ¼ [0.42, 0.59]). Refer to Table 2 for summary of findings.

In order to test the second research question of whether

there was a difference in the overall mean absences during

the 2 SLIV years between students who were vaccinated

in the SLIV program and those who were not, an indepen-

dent t test compared aggregate absenteeism of Group B-V

(2.39 days) and Group B-U (3.03 days), yielding a statisti-

cally significant difference of .64 (p < .0001, 95% CI ¼ [0.51, 0.78]). Refer to Table 2 for summary of findings.

Table 1. Description of Students by Gender, Race, SLIV Participation.

Variable

Pre-SLIV Years SLIV Years

2007–2008 2008–2009 2010–2011 2011–2012 N (%) N (%) N (%) N (%)

Total students 4,764 (100%) 5,201 (100%) 4,797 (100%) 4,799 (100%) Gender

Male 2,435 (51%) 2,667 (52%) 2,483 (52%) 2,483 (52%) Female 2,329 (49%) 2,534 (48%) 2,314 (48%) 2,316 (48%)

Race White, non-Hispanic 3,701 (78%) 4,018 (77%) 3,696 (77%) 3,699 (77%) Black 668 (14%) 721 (14%) 667 (14%) 684 (14%) Hispanic 169 (4%) 206 (4%) 193 (4%) 180 (4%) American Indian or Alaska Native 5 (<1%) 8 (<1%) 8 (<1%) 6 (<1%) Multiracial 174 (4%) 203 (4%) 183 (4%) 189 (4%) Asian or Pacific Islander 42 (1%) 39 (1%) 42 (1%) 35 (1%) Unknown 5 (<1%) 6 (<1%) 8 (<1%) 6 (<1%)

SLIV participation Yes NA NA 940 (20%) 1,230 (26%) No 3,856 (80%) 3,569 (74%)

Average # of days absent (stan. dev) 2.4 (2.7) 2.7 (2.6) 3.2 (2.9) 2.6 (2.8)

Note. stan. dev ¼ standard deviation; SLIV ¼ school-located influenza vaccine.

Plaspohl et al. 77

Discussion

The findings in this study reflect one example of the possible

impact of an SLIV program on student absenteeism. Ele-

mentary students within one rural school system had access

to receiving a primary prevention service, influenza immu-

nization, from the local health department and school nurses

within their normal school setting. This particular time

period was selected because it allowed time for the immuni-

zations to take effect after administration and also because it

represented the time period of a typical flu season.

In order to assess the potential impact of the SLIV pro-

gram on absenteeism, 2 years of aggregate pre-SLIV atten-

dance data were compared to similar information for 2

years during which time the SLIV program was in place,

thus enabling the researchers to utilize a baseline for the

measurement. Overall, average absenteeism for the first year

was 2.4 days per student during the 80 class days following

the seasonal holidays in December, with a subsequent

increase during the following 2 years to 2.7 and 3.2 days, fol-

lowed by a drop in the fourth year down to 2.6. Data analysis

led to the conclusion that there was a statistically significant

difference in the average number of absences between

Group A and Group B; however, instead of seeing a decline

in overall absences after SLIV implementation, there was an

increase during 2010–2011. With a 95% CI of 0.28 and 0.44 for the 0.36-day difference between these two groups, the

clinical importance is questionable. Upon preliminary

review, one might challenge whether the SLIV program had

an impact at all with this opposite-than-expected result.

Researchers conducted more analysis to study this unantici-

pated finding. Further exploration of the data revealed that

the results for the subset of students vaccinated in SLIV

(Group B-V) were lower than the aggregate pre-SLIV

(Group A) absenteeism average (2.39 vs. 2.53), for a differ-

ence of 0.14 days, with a 95% CI of 0.02 and 0.26. A similar comparison between Group A and Group B-U reflected a

higher average absenteeism among Group B-U (3.03 vs.

2.53), for a difference of 0.5 days, with a 95% CI of 0.42 and 0.59. Both of these findings were statistically significant

with p < .0001. On average, Group B-V missed fewer school

days than Group A, while Group B-U missed more school

days than Group A. Again, one could question the clinical

significance of these findings; however, the difference

between Group B-U and Group A absences potentially

exceeded a half day, suggesting a somewhat stronger rela-

tionship between these variables.

The final independent t test to assess differences between

absenteeism for Group B-V compared to Group B-U pre-

sented a difference of 0.64 days between the two subsets,

with 95% CI of 0.51 and 0.78. This finding was also statis- tically significant at p < .0001 and was the largest difference

among all inferential analyses. Group B-V students were in

their seats for almost a full day more than Group B-U

students.

Student participation in the SLIV program increased from

20% to 26% during the 2 years of program administration. As participation increased over this period of time, the aver-

age number of days absent decreased for both Group B-V

and Group B-U, suggesting that the increased utilization of

2.4 2.7

3.2

2.6

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

2007-08 2008-09 2010-11 2011-12

Days

SLIV YearsPre-SLIV Years

Figure 1. Average absenteeism by school year.

3.3

2.82.7

2.2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

2011-122010-11 Not Vaccinated in SLIV Vaccinated in SLIV

Days

Figure 2. Average absenteeism by school-located influenza vaccine (SLIV) participation.

Table 2. Two-Group Comparisons for Mean Days Absent.

Group A (N ¼ 9,965)

Group B (N ¼ 9,596)

Group B-V (N ¼ 2,170)

Group B-U (N ¼ 7,426)

Difference Between Groups

95% CI for Difference Between Groups

2.53 2.89 – – 0.16* [0.28, 0.44] 2.53 – 2.39 – 0.14* [0.02, 0.26] 2.53 – – 3.03 0.50* [0.42, 0.59]

– – 2.39 3.03 0.64* [0.51, 0.78]

* p < .001.

78 The Journal of School Nursing 30(1)

the program may have a substantial correlation with increased

herd immunity. If SLIV participation continues to increase in

the future, will absenteeism continue to decline?

Strengths and Limitations

There are several strengths that can be identified for this

study. First, the study utilized a population, not a sample,

as retrospective data for all Effingham County public ele-

mentary school students (K-5) were included in the analysis.

This was the first study in Georgia to assess the potential

impact of a local SLIV program on student attendance.

Many of the existing studies on this topic were sponsored

by major pharmaceutical companies that produce immuniza-

tion vaccines; however, this current research was not indus-

try sponsored, thus eliminating the potential for a conflict of

interest. This study was a collaborative project involving

multiple stakeholders, including a state health district, local

health department, two public state universities, and a local

county BOE, enabling a rich synthesis of expertise and

knowledge to yield a successful project focused on public

health and primary prevention for school children.

As with all studies, there are limitations to be recognized

as well. This study did not address/identify other locations

where students could obtain influenza immunization (e.g.,

pediatrician’s office, health department, etc.). Researchers

recognized that some students were immunized at other

locations, thus eliminating their need to participate in the

SLIV program. Although these students did not access

SLIV, the fact that they were immunized should have con-

tributed to the resulting absentee averages in a positive man-

ner. Another limitation includes the fact that researchers

were not able to differentiate between causes associated with

student absences, being unable to correlate SLIV administra-

tion with reduction in absences directly due to influenza and

also not being able to distinguish the variation in severity of

absence-causing illnesses.

Implications for School Nursing Practice

School nurses can benefit from this study, because the data

provide them with credible scientific evidence to support the

justification, establishment, and/or continuation of an SLIV

program within their local school setting. This study allows

them an opportunity to learn about an interdisciplinary, col-

laborative effort between partners within a community who

worked together and applied preexisting information to sup-

port a public health initiative that ultimately keeps students

healthier and in the classroom, helping to minimize their

absences and contributing to enhanced herd immunity to

benefit not just the students but also the school faculty and

staff, student families and friends, and other members of the

community who interact with the immunized students. Study

results may encourage school nurses to adopt an active role

supporting an increase in school-located immunizations via

initiation of collaborative programs, monitoring overall

immunization rates, and informing the school community

about the relationship of immunization and attendance.

Conclusion

As previously established, the literature provides evidence

that student attendance in school increases the likelihood

of their academic success. Reducing absenteeism by as little

as 1 day correlates to improvement in academic performance

(U.S. Department of Education, 2009). This study has con-

tributed to scientific evidence by demonstrating the potential

impact of an SLIV program on reducing student absences

that may be due to influenza. If students have convenient

access to this type of primary prevention within their school

setting, they should be better able to maintain optimal health

that will allow them to miss fewer days of school due to

illness and thus be more successful in their academic and

future professional careers. This study examined two

sequential influenza seasons in which students had access

to an SLIV program, and this short amount of time may not

adequately establish trends related to absenteeism. Thus, the

research team plans to add another year of absenteeism data

for the 2012–2013 academic school year, using the same

methodology, to further explore a longer longitudinal trend

and strengthen reliability of findings. Future research on

efficacy of SLIV programs may focus on exploring a more

direct link between SLIV participation and herd immunity

among other populations within a school setting such as

faculty, school nurses, and staff.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with

respect to the research, authorship, and/or publication of this

article.

Funding

The author(s) received no financial support for the research, author-

ship, and/or publication of this article

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Author Biographies

Sara S. Plaspohl, DrPH, CHES, is an assistant professor of health

sciences, at the Armstrong Atlantic State University, Savannah,

GA, USA.

Betty T. Dixon, DrPH, RN, is a director of Clinical and Nursing

Services, at the Coastal Health District, Savannah, GA, USA.

James A. Streater, EdD, CHES, is a professor of health sciences,

at the Armstrong Atlantic State University, Savannah, GA, USA.

Elizabeth T. Hausauer, MSN,RN, is the immunizations coordina-

tor, at the Coastal Health District, Savannah, GA, USA.

Christopher P. Newman, MPH, is a graduate student at the Arm-

strong Atlantic State University, Savannah, GA, USA.

Robert L. Vogel, PhD, is a professor of biostatistics, at the Georgia

Southern University.

80 The Journal of School Nursing 30(1)

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