ORIGINAL ARTICLE

Development and testing of an instrument to assess nurses’ knowledge,

risk perception, health beliefs and behaviours related to influenza

vaccination

Jing Zhang, Alison E While and Ian J Norman

Aims and objectives. To develop an instrument to measure nurses’ knowledge, risk perception and health beliefs towards influenza

and influenza vaccination and their vaccination behaviours and evaluate its construct validity and internal consistency reliability.

Background. Although instruments to assess predictors of nurses’ vaccination behaviours have been developed, their validity and

reliability have not been reported.

Design. Instrument development and initial validity and reliability testing.

Methods. The instrument was developed drawing on a literature review and expert consultation and was refined through pilot

work. A cross-sectional survey using a revised version of the instrument was conducted among a convenience sample of 520

registered nurses (response rate 77Æ4%). Cronbach’s alpha coefficient was calculated to determine internal consistency of the sub-

scale in the instrument. Principal components analysis with varimax rotation was carried out to evaluate the instrument’s construct

validity and examine its internal structure.

Results. Cronbach’s alpha coefficients for the three newly developed scales ranged from 0Æ70–0Æ76. Principal components analysis

produced a good fit and confirmed the internal design of the instrument. In the seasonal influenza knowledge sub-scale four factors

explained 44Æ8% of the total variance; in the H1N1 knowledge sub-scale two factors explained 44Æ7% of the total variance. Three

factors in the risk perception scale contributed 50Æ5% of the total variance and two factors in the vaccination behaviours scale

contributed 62Æ1% of the total variance.

Conclusions. An instrument has been developed to assess nurses’ knowledge, risk perception and health beliefs towards influenza

and influenza vaccination and their vaccination behaviours. The instrument was valid and reliable for the setting where it was used.

Relevance to clinical practice. This instrument could be used to assess nurses’ knowledge, risk perception, health beliefs towards

influenza and influenza vaccination and their vaccination behaviours. The three newly developed scales could also be used

independently to measure variables influencing nurses’ vaccination practices.

Key words: behaviours, influenza vaccination, instrument development, knowledge, nurses, risk perception

Accepted for publication: 26 March 2011

Introduction

Influenza is an acute viral infection that spreads easily from

person to person. In temperate regions influenza epidemics

occur almost annually and have been shown to be associated

with short-term increases in severe morbidity and overall

mortality (WHO 2009a). Vaccination is commonly recogni-

sed as the principal measure for preventing influenza and

reducing the impact of epidemics (WHO 2005). High-risk

groups are usually targeted for influenza vaccination as well

Authors: Jing Zhang, MSc, Associate Professor, Second Military

Medical University, School of Nursing, Shanghai, China; Alison E

While, PhD, Professor, King’s College London, Florence Nightingale

School of Nursing and Midwifery; Ian J Norman, PhD, Professor,

King’s College London, Florence Nightingale School of Nursing and

Midwifery, London, UK

Correspondence: Alison E While, Professor, King’s College London,

Florence Nightingale School of Nursing and Midwifery, James Clerk

Maxwell Building, 57 Waterloo Road, London SE1 8WA, UK.

Telephone: +44 20 7848 3022.

E-mail: alison.while@kcl.ac.uk

� 2012 Blackwell Publishing Ltd

Journal of Clinical Nursing, doi: 10.1111/j.1365-2702.2011.03794.x 1

as those with regular, frequent contact with high-risk people,

such as healthcare workers (HCWs) (WHO 2000, 2005,

Poland et al. 2005, Centres for Disease Control and Preven-

tion 2007, Straetemans et al. 2007). However, studies have

shown that vaccination rates of HCWs remain suboptimal

worldwide (Harrison & Abbott 2002, Lester et al. 2003,

Abramson & Levi 2008, Blank et al. 2008, Maltezou et al.

2008, Mereckiene et al. 2008) and nurses, although a group

that has the most patient contact, are more reluctant to

receive vaccination compared with other HCWs (Martinello

et al. 2003, Brunton et al. 2005, O’Reilly et al. 2005,

Christini et al. 2007, de Juanes et al. 2007, Livni et al.

2008, Norton et al. 2008, Shahrabani et al. 2009).

Several studies have been conducted to explore the

variables contributing to the uptake or refusal of vaccination

among nurses. A strong association between nurses’ knowl-

edge of influenza and influenza vaccination and their vacci-

nation status has been noted in various surveys (Martinello

et al. 2003, O’Reilly et al. 2005, Willis & Wortley 2007,

Livni et al. 2008, Falomir-Pichastor et al. 2009, Shahrabani

et al. 2009), that is, vaccinated nurses have significantly

higher knowledge scores or are more likely to answer

knowledge questions correctly. Attitudes towards influenza

and vaccination, including the perception of risk related to

influenza or pandemics, have been identified as another major

variable influencing nurses’ decision-making about vaccina-

tion (Campos & Jalaludin 2003, Brunton et al. 2005,

O’Reilly et al. 2005, Chalmers 2006, Tam et al. 2008,

Shahrabani et al. 2009). Several studies have suggested other

predictors associated with nurses’ vaccination including age,

previous vaccination history, professional ethos, group iden-

tification and health motivation (Campos & Jalaludin 2003,

Ofstead et al. 2008, Falomir-Pichastor et al. 2009, Norton

et al. 2008, Shahrabani et al. 2009).

Vaccination campaigns have attempted to improve vacci-

nation rates among HCWs in some local settings but these

campaigns have not always obtained the expected outcomes

among nurses (Harbarth et al. 1998, Sartor et al. 2004,

Ofstead et al. 2008) although others have reported increased

vaccination coverage of HCWs (Bryant et al. 2004, Kuntz

et al. 2008, Ribner et al. 2008, Polgreen et al. 2009). We

hypothesise that this may be due to variables influencing

nurses’ vaccination behaviours that have not been clearly

identified because the instruments used in the above studies

were not systematically developed and tested.

There are few reports detailing rigorously developed

instruments with validity and reliability testing. This paper

describes the development and testing of an instrument (the

King’s Nurses’ Influenza Vaccination Questionnaire) to

measure nurses’ knowledge, risk perception, health beliefs

relating to influenza and influenza vaccination as well as

vaccination behaviours. This instrument could aid the

exploration of variables which influence nurses’ vaccination

decisions so that vaccination campaigns may be evidence-

based.

Background

A literature search revealed 15 different instruments to assess

nurses’ knowledge, attitudes, risk perception, or health

beliefs towards influenza and influenza vaccination. How-

ever, for most of these instruments few details about their

development or validity and reliability testing were reported.

Five instruments were developed as part of surveys.

Martinello et al. (2003) developed a questionnaire to mea-

sure HCWs’ knowledge regarding influenza vaccination and

risk perception about the spread of influenza and used it in a

cross-sectional survey in a US hospital. A self-administered

questionnaire was developed by O’Reilly et al. (2005) to

assess influenza vaccination status, reasons for or against

vaccination, knowledge and attitudes towards influenza

vaccination using a Likert scale for nurses working in elderly

care units from three hospitals in the UK. An Israeli cross-

sectional survey of physicians and nurses used a three-section

questionnaire to assess participants’ occupational data,

knowledge about influenza vaccine and reasons for taking

or not taking a vaccination (Livni et al. 2008). Falomir-

Pichastor et al. (2009) surveyed a large convenience sample

of nurses in Switzerland using a self-developed tool compris-

ing a 11-point scale to assess vaccination status and intention,

reasons for or against vaccination, perceived negative conse-

quences of vaccination, group identification and professional

duties. A short questionnaire was developed by Christini

et al. (2007) to assess vaccination status and intention,

motivating factors for vaccination, degree of contact with

high-risk individuals, perceived risk of side effects of vaccine

and incidence of influenza-like illness among HCWs in two

US hospitals. All these instruments were developed to

measure important aspects of influencing factors underlying

influenza vaccination behaviours among HCWs or nurses,

but the absence of evidence relating to questionnaire devel-

opment and subsequent testing raises questions about their

rigour and wider utility.

Two instruments drew on previous studies. Campos and

Jalaludin (2003) developed a questionnaire to assess the

predictive factors underlying influenza vaccination and beliefs

and knowledge of influenza and vaccine among hospital-

based nurses. The first element of the questionnaire was

modified from a questionnaire originally developed by

Chapman and Coups and used with a large convenience

J Zhang et al.

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2 Journal of Clinical Nursing

sample of healthy adults in US (Chapman & Coups 1999a,b).

However, both original papers and the later paper did not

report details about the questionnaire development and

testing. Another element of the questionnaire sought to

measure Health Belief Model (Becker et al. 2004) variables

drawing on Shahrabani et al.’s (2009) instrument which was

based on the questionnaire of Blue and Valley (2002) with no

evidence of validity and reliability testing. Another instru-

ment drew on a previous survey undertaken in Australia

which had been used to survey HCWs in China (Seale et al.

2010). Again there was no report of instrument testing nor

general translation and back-translation or of a cultural

adjustment phase which is usual when an instrument has

been developed for another context.

Six studies reported a pilot test before the field survey. A

New Zealand version of questionnaires assessing knowledge

and attitudes of general practitioners about influenza vacci-

nation (Brunton et al. 2005) was developed drawing on a

previous study carried out in Australia (Litt et al. 1995). The

questionnaire was pilot tested with a small group before use

in the main study but no details of the pilot testing and

results were reported. Tam et al. (2008) developed a ques-

tionnaire to assess nurses’ experience with SARS, attitudes

towards the avian influenza epidemic and views on influenza

vaccination uptake in Hong Kong. Although a pilot study is

reported, no details were provided. Further, section two of

their questionnaire seeking nurses’ views towards the avian

influenza epidemic was adapted from Imai et al.’s (2005)

study which also did not report testing by the original

researchers. A US survey administered an online question-

naire developed from a literature review and consultation

with experts to collect data about influenza vaccination

history and vaccination intention, reasons for declining

vaccination, knowledge about vaccination and cues to action

amongst nurses (Ofstead et al. 2008). Although it was pilot

tested and revised prior to the main data collection, the

validity and reliability of the questionnaire were not

reported. Several instruments were pilot tested with conve-

nience samples to ensure clarity and ease of administration

(Chalmers 2006, Norton et al. 2008, Clark et al. 2009).

Chalmers (2006) reported pre-testing and piloting of the

questionnaire prior to refinement of its design and content to

increase its reliability, validity and practicability but the pilot

study results were not reported.

We found no valid and reliable instrument that had been

developed to measure nurses’ knowledge, risk perception,

health beliefs, vaccination behaviours and other important

variables. Hence, this study aimed to develop an instrument

and evaluate it for construct validity and internal consistency

reliability.

Method

Aim

The study aimed to develop and test an instrument to

measure nurses’ knowledge, risk perception and behaviour

relating to influenza and influenza vaccination.

Design

A cross-sectional, descriptive instrument development study

was designed. The instrument measuring nurses’ knowledge,

risk perception, health beliefs and behaviours relating to

influenza vaccination was developed and tested using three

steps: (1) Construction of the instrument: an initial draft of the

instrument was developed from the literature review and

expert consultation. The initial draft instrument was reviewed

by experts to assess content validity. (2) Testing for clarity and

feasibility for use: a pilot survey was conducted to test the

clarity and feasibility of the revised instrument in a small

sample of nurses and a revised version of the instrument was

developed. (3) Assessment of validity and reliability: the new

version of the instrument was distributed to a large sample of

nurses to calculate the internal consistency coefficient of the

instrument. The data were also subjected to exploratory factor

analysis to test construct validity.

Ethical considerations

The study was approved by the University’s Research Ethics

Committee. All participation was voluntary, confidential and

anonymous.

Step 1: Construction of the instrument

Key components of the instrument were derived from an

overview of the existing literature about the determinants of

nurses’ influenza vaccination behaviours (Zhang et al. 2010).

These factors and predictors were used to generate a

preliminary list of items for the instrument focusing on the

following areas:

• Demographic data of nurses including gender, age group,

educational qualifications, work place, clinical speciality

and years of registration as a nurse and direct patient

contact.

• Knowledge about influenza and the influenza vaccination.

• Perception of the risk of influenza and pandemics.

• Health beliefs.

• Practices regarding influenza vaccination.

• Reasons for having or not having the influenza vaccination.

Original article Nurses’ influenza vaccination instrument

� 2012 Blackwell Publishing Ltd

Journal of Clinical Nursing 3

The preliminary list of items was discussed with two nurse

experts (co-literature reviewers) who checked whether the

items represented key content. Wording and comprehension

of the items as well as scoring methods were also checked

with the statistician involved in the first step. For each of the

items, experts were asked if the wording was clear, if the item

fitted with the aim of study and if the item was needed. Two

open-items were suggested by the statistician to replace of

original closed items because open items ‘provide forthright

and valuable insights into people’s perceptions of the issues

involved and to get a feel for the words and phrases that they

use’ (Jackson & Furnham 2000, p. 116). Feedback from the

experts resulted in the adjustment of the wording for several

of the items and two open items replaced the closed items.

Changes were introduced and another draft of the instrument

was produced.

Step 2: Testing for clarity and feasibility for use

A pilot study was conducted to ensure that the revised

instrument was clear, understandable and feasible for use in a

sample of nurses. Twelve nurses enrolled in a university

continuing professional development course were invited to

participate in the pilot study. They were asked to complete

the initial draft of the instrument and afterwards they were

asked to provide their comments about problems in com-

pleting it, including whether it was clear and understandable

and also whether the content was complete and relevant

(Polit & Hungler 1993). Only four of those invited agreed to

participate in the pilot study (six declined; two were absent

from the class). They completed the instrument with no item

non-response within 7–15 minutes. The instrument was

considered easy to complete and not long. All items were

considered relevant to the aim of study and no suggestions

were made regarding the exclusion of any items or the

addition of new items. No items were ambiguous or caused

unease. However, suggestions were made regarding the

instrument’s layout so that it would be more compressed

and look shorter. A final version of the instrument was

developed.

The final version comprised six sections, combining open

and closed items to measure nurses’ knowledge, risk percep-

tion towards influenza and the influenza vaccination as well

as their vaccination behaviours:

Section one (30 items): asks nurses to assess true or false

of statements relating to knowledge about influenza and the

influenza vaccination (including 22 items about seasonal

influenza and vaccination and eight items about H1N1 and

vaccination). The correct response to each item was based

on the World Health Organization (WHO) guidelines

(WHO 2000, 2009a,b,c,d). The correct answers for 19

items required a positive response while the other 11 items

required a negative response. We quantified the degree of

knowledge by calculating the knowledge (K) score. The

original K-score was defined as the total number of correct

(either positive or negative) answers to the 30 items; the

maximum possible original K-score was 30. There were

also two sub-scores for knowledge: seasonal knowledge

(SK) score and H1N1 knowledge (HK) score, with the

maximum possible score of 22 and 8 respectively. We also

converted the original scores to a 100% scoring system

where K, SK and HK% with scores ranging from 0–100%

respectively.

Section two (12 items): a four-point Likert scale was used

to assess nurses’ perception of risk towards influenza and

pandemic. We quantified the degree of concept of risk

perception by calculating the risk perception (R) score.

Responses to items were positive except one item (B3_5)

which was needed to be reversed when calculating the R

score. The R-score was defined as the average of the values

ticked for each item (i.e. where 1, strongly disagree; 4,

strongly agree; 0, not decided) with item B3_5 needing to be

reversed before summing. R score is ranging of 0–4.

Section three (18 items): The Multidimensional Health

Locus of Control (MHLC) scale (Wallston 1993) was used to

examine nurses’ beliefs regarding whether his or her health

status is determined by the actions of individuals and if so,

whether the locus of that control is ‘internal’, ‘chance’ or

‘powerful others’. The MHLC is an 18-item, six-point Likert-

type questionnaire including three subscales. The score on

each sub-scale is the sum of the values ticked for each item

(i.e. where 1, strongly disagree and 6, strongly agree). No

items need to be reversed before summing. All of the sub-

scales are independent of one another. The full scale has

acceptable test–retest reliability with coefficients ranging

from r = 0Æ60–0Æ70 and internal consistency with coefficients

ranging from a = 0Æ60–0Æ75 (Wallston 2005).

Section four (nine items): assesses nurses’ practices relating

to seasonal influenza and H1N1 vaccination. Nurses are

asked to indicate whether or not: (1) they had been

vaccinated in the last 12 months; (2) they had recommended

vaccine to their patients in the past; (3) they intend to receive

vaccination in the following year and (4) they intend to

recommend vaccinations to their patients in the future. An

open item also asked about their vaccination practices over

the last five years. Responses to these items constitute the

main dependent variables of the study.

Section five (two open items): reasons for accepting or

refusing vaccination are asked inviting three reasons why

they might (or not) have the vaccination.

J Zhang et al.

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4 Journal of Clinical Nursing

Section six (10 items): demographic and professional data

are sought including gender, age group, educational qualifi-

cations, place of work, speciality, years as a registered nurse

and whether or not they have direct patient contact.

Step 3: Assessment of reliability and construct validity

A survey using the final version of the instrument to test

validity and reliability of the instrument was conducted

among a large convenience sample of qualified nurses

attending university continuing professional development

courses between May–November 2010 using a self-complete

questionnaire. A total 936 qualified nurses attending 39

classes were invited to participate in the survey (some may

have been invited more than once if they attended more than

one class but they were reminded they should only participate

on one occasion). One of the researchers distributed the

information sheets directly to potential participants and

questionnaires if they agreed to participate in the survey. A

freepost addressed envelope was provided to enable all

completed questionnaires to be returned directly to the

researchers. Non-response was not followed up because the

questionnaire completion was anonymous.

All items were designed to contribute to the same under-

lying construct of vaccination and therefore, the Cronbach’s

alpha coefficient was used to determine the internal consis-

tency reliability of sections 1–4 of questionnaire (Dunn

1989). Values of Cronbach’s alpha above 0Æ70 are considered

to be indicative of good internal reliability (consistency)

(Nunally 1978).

Exploratory factor analysis (EFA) was initially performed

to examine the internal structure of the section one (knowl-

edge), two (risk perception) and four (vaccination behav-

iours). Conditions for the adequacy of the factor analysis

were checked first based on: (1) a sample size of a minimum

of 1:5 items to subject ratios for the reliability of the factors

emerging; (2) significant Bartlett’s test of sphericity and (3)

large values of the Kaiser–Meyer–Olkin (KMO). Principal

components analysis and varimax rotation with Kaiser

normalisation were selected for the factor extraction in this

study. The Kaiser’s criterion based on eigenvalues and the

Scree test was used for calculating the factors’ numbers as

well as a subjective evaluation of how meaningfully the items

loaded on factors (Jackson & Furnham 2000, Waston &

Thompson 2006).

Statistical analysis

Statistical analysis was performed using SPSSSPSS 15.0 software

(SPSS Inc., Chicago, IL, USA). Data were first analysed using

descriptive statistics including mean and standard deviation

(SD). Cronbach’s alpha coefficients and factor analysis

(principal component analysis with varimax rotations) was

used to examine which factors of the sections comprised

coherent groups of items (Knapp & Brown 1995).

Results

Descriptive statistics

A total of 520 registered nurses completed the questionnaire

from 672 distributed (77Æ4% response rate). The character-

istics of respondents are summarised in Table 1. Most of the

nurses were female (84Æ0%) and worked in hospitals (79Æ2%)

and 91Æ7% of the sample reported having direct patient

contact. Overall 187 of 506 respondents (37Æ0%) reported

receiving the influenza vaccination in the last 12 months; and

35Æ3% (172 of 487) of the respondents reported receiving the

H1N1 vaccination in 2009.

Reliability

The mean scores for the knowledge and risk perception scales

were: K% 69Æ7 (SD 12Æ26, n = 494); SK%73Æ2 (SD 11Æ73,

n = 503); HK% 59Æ4 (SD 23Æ61, n = 507); and R 2Æ3 (SD

0Æ44, n = 510). Cronbach’s alpha coefficients ranged from

0Æ701–0Æ763 for each scale of instrument with alpha coeffi-

cients of 0Æ639–0Æ731 for the sub-scales of knowledge and

sub-scales of MHLC scale (Table 2). Thus, all scales of the

questionnaire met the internal consistency criterion of at least

0Æ70 for a newly developed instrument (Nunally & Bernstein

1994).

Factor analysis

As the instrument was constructed to comprise six sections

based on an analysis of relevant references, a separate factor

analysis was done on each of the seasonal influenza knowl-

edge, HK, risk perception and vaccination behaviours scales.

For the former three scales, the KMO test values, which

measures the sampling adequacy, were >0Æ60 (0Æ672, 0Æ739

and 0Æ667, respectively) indicating that a factor analysis

could be performed and all the significance values of

Bartlett’s Test of Sphericity were less than 0Æ001 indicating

the suitability of the data for factor analysis. The KMO value

of the vaccination behaviours scale was 0Æ576 with Bartlett’s

p value less than 0Æ001 so that EFA was also performed. The

ratios of sample size to the number of items ranged from

1:18Æ0 (for the seasonal influenza knowledge sub-scale) and

1:59Æ6 (for the vaccination behaviours scale) indicated the

Original article Nurses’ influenza vaccination instrument

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Journal of Clinical Nursing 5

reliability of the factors emerging. Principal component

analysis with varimax with Kaiser normalisation was used

and results are set out in Table 3.

An EFA of seasonal influenza knowledge sub-scale was

performed revealing nine factors with seven items focusing on

seasonal influenza vaccination. The items relating to recom-

mended groups were excluded from the analysis and auto-

matically seen as a separate factor. Item A1_6 was also

excluded because of a low factor loading (<0Æ4) and less

relevance to any potential factor based on the subjective

evaluation of the meaning. Analysis of the results for the

remaining 14 items identified four relevant factors which

cumulatively explained 45Æ54% of total variance. The factors

corresponded to knowledge relating to influenza vaccination,

high-risk groups, severity of influenza and general informa-

tion relating to influenza. Analysis of the HK sub-scale

identified two factors with cumulative eigenvalues of 45Æ03%

of total variance which were entitled knowledge relating to

H1N1 and H1N1 vaccination. Three relevant factors with a

cumulative 50Æ67% contribution to the total variance were

identified for the risk perception scale which represents the

perception of the negative consequences of contracting

influenza, personal vulnerability to illness and severity of

influenza. Two factors were identified for the vaccination

behaviours scale defined as patient vaccination recommen-

dation and personal vaccination with contributing 62Æ1% of

the total variance.

Examination of the internal structure

In designing the knowledge, risk perception and vaccination

behaviours scales of the instrument, it was hypothesised that

these scales would contain the followed concepts:

• Knowledge about seasonal influenza and influenza

vaccination which would include general information

about seasonal influenza (A1_1–4), serious outcomes of

influenza (A1_5–7), general information about influenza

vaccination (A1_8–12), high-risk groups of influenza

(A1_13–15) and recommended groups for influenza

vaccination (A16–22).

• Knowledge about H1N1 (A2_1,3–5) and H1N1 vacci-

nation (A2_2,6–8).

• Perception of the risk towards the negative consequences

of contracting influenza (B3_1–4), serious complications

and possibility of death after contracting influenza

(B3_7–10) and personal vulnerability to influenza and

illnesses (B3_5,6,11,12).

• Nurses’ vaccination behaviours (D5_1, D5_2, D7_1,

D7_2) and recommendation vaccination behaviours to

their patients (D6_1, D6_2, D8_1, D8_2).

Table 2 Internal consistency of instrument

Section of instrument

No. of

items

Cronbach’s

alpha

Valid,

n (%)

Knowledge scale 30 0Æ763 377 (72Æ5)

SK sub-scale 22 0Æ658 396 (76Æ2)

HK sub-scale 8 0Æ706 477 (91Æ7)

Risk perception scale 12 0Æ701 483 (92Æ9)

Vaccination behaviour scale 8 0Æ756 450 (86Æ5)

MHLC scale 18 0Æ723 457 (87Æ9)

MHLC-internal subscale 6 0Æ652 483 (92Æ9)

MHLC-chance subscale 6 0Æ639 484 (93Æ1)

MHLC-powerful others

subscale

6 0Æ731 495 (95Æ2)

Table 1 Characteristics of respondents (n = 520)

Demographic features Number (%)

Gender

Male 63 (12Æ1)

Female 437 (84Æ0)

Missing data 20 (3Æ8)

Age

20–29 years 121 (23Æ3)

30–39 years 193 (37Æ1)

40–49 years 134 (25Æ8)

50 years or older 51 (9Æ8)

Missing data 21 (4Æ0)

Education

DipHE 208 (40Æ0)

Bachelor Degree 221 (42Æ5)

PGDip 11 (2Æ1)

Masters 20 (3Æ8)

Others 33 (6Æ3)

Missing data 27 (5Æ2)

Work place

Hospital 408 (78Æ5)

Community 75 (14Æ5)

Both 9 (1Æ7)

University 1 (0Æ2)

Missing data 27 (5Æ2)

Speciality

Medicine 195 (37Æ5)

Mental health 37 (7Æ1)

Surgery 119 (22Æ9)

Older people 20 (3Æ8)

Paediatrics 40 (7Æ7)

Maternity 19 (3Æ7)

Primary care 41 (7Æ9)

Ambulatory care 18 (3Æ5)

Missing data 31 (6Æ0)

Direct patient contact

Yes 477 (91Æ7)

No 17 (3Æ3)

Missing data 26 (5Æ0)

Qualified years (years) 11Æ90 ± 8Æ754 (n = 482)

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6 Journal of Clinical Nursing

The above results of factor analysis verified our hypotheses

at the factor level except item A1_6, which relates to the

economic impact of influenza epidemic, achieving a factor

loading of less than 0Æ4 and the cross-loading with three factors

as well as subjective evaluation were not meaningful for a

latent factor, as suggested by Pallant (2001) and was therefore

removed from the seasonal influenza knowledge sub-scale.

Further internal consistency assessments were performed on

the seasonal influenza knowledge sub-scale and knowledge

scale and achieved Cronbach’s alpha coefficients of 0Æ66 and

0Æ76, respectively. Finally, Cronbach’s alpha coefficients of

0Æ76, 0Æ70 and 0Æ76 for knowledge, risk perception and

Table 3 Factor analysis of knowledge, risk perception and vaccination behaviours scales (n = 520)

Scale or subscale Label

Total variance explained

Item Rotated componentTotal

Variance

(%)

Cumulative

(%)

Seasonal influenza

knowledge sub-scale*

1. Influenza vaccination 2Æ295 16Æ396 16Æ396 A1_10 0Æ694 0Æ104 0Æ053 �0Æ055

A1_11 0Æ679 0Æ163 �0Æ033 0Æ172

A1_9 0Æ612 0Æ076 0Æ196 �0Æ086

A1_8 0Æ604 �0Æ010 �0Æ045 �0Æ046

A1_12 0Æ537 �0Æ114 0Æ207 0Æ118

2. High-risk groups 1Æ472 10Æ517 26Æ913 A1_15 �0Æ106 0Æ737 0Æ103 �0Æ065

A1_14 0Æ171 0Æ711 �0Æ102 �0Æ063

A1_13 �0Æ045 0Æ631 0Æ147 0Æ125

3. Severity of influenza 1Æ325 9Æ463 36Æ376 A1_5 0Æ046 0Æ091 0Æ767 0Æ003

A1_7 �0Æ039 0Æ016 0Æ760 0Æ137

4. General information of influenza 1Æ177 8Æ408 44Æ784 A1_2 �0Æ062 0Æ082 0Æ142 0Æ637

A1_1 0Æ034 �0Æ047 0Æ098 0Æ592

A1_3 �0Æ142 �0Æ032 �0Æ058 0Æ512

A1_4 0Æ259 �0Æ045 0Æ043 0Æ385

HK sub-scale 1. H1N1 2Æ427 30Æ342 30Æ342 A2_4 0Æ673 0Æ122

A2_1 0Æ658 �0Æ089

A2_5 0Æ617 0Æ174

A2_3 0Æ528 0Æ178

2. H1N1 vaccination 1Æ148 14Æ350 44Æ692 A2_7 0Æ063 0Æ832

A2_6 0Æ116 0Æ785

A2_8 0Æ365 0Æ451

A2_2 0Æ349 0Æ436

Risk perception scale 1. Negative consequences of

contracting influenza

2Æ889 24Æ074 24Æ074 B3_10 0Æ841 �0Æ013 0Æ035

B3_9 0Æ793 0Æ159 0Æ073

B3_8 0Æ600 �0Æ014 0Æ106

B3_7 0Æ529 0Æ156 0Æ098

2. Personal vulnerability to illness 1Æ784 14Æ864 38Æ938 B3_4 �0Æ031 0Æ769 0Æ076

B3_3 �0Æ039 0Æ758 0Æ021

B3_1 0Æ141 0Æ659 0Æ097

B3_2 0Æ204 0Æ580 0Æ033

3. Severity of influenza 1Æ384 11Æ536 50Æ474 B3_12 0Æ136 0Æ083 0Æ725

B3_6 0Æ149 �0Æ127 0Æ665

B3_5 �0Æ065 0Æ058 0Æ649

B3_11 0Æ221 0Æ227 0Æ529

Vaccination

behaviours scale

1. Patient vaccination

recommendation

3Æ148 39Æ352 39Æ352 D8_1 0Æ861 0Æ087

D8_2 0Æ834 0Æ049

D6_1 0Æ832 0Æ114

D6_2 0Æ823 0Æ116

2. Personal vaccination 1Æ820 22Æ753 62Æ104 D7_1 0Æ119 0Æ812

D7_2 0Æ085 0Æ737

D5_1 0Æ050 0Æ698

D5_2 0Æ066 0Æ636

*Except seven items relating to the seasonal influenza vaccination recommended groups.

Bold values indicate factor loading on the identified concepts within the different sub-scales.

Original article Nurses’ influenza vaccination instrument

� 2012 Blackwell Publishing Ltd

Journal of Clinical Nursing 7

vaccination behaviours scales provided evidence of internal

consistency reliability of these scales of the instrument.

Discussion

This study addressed the development of an instrument to

measure nurses’ knowledge, risk perception, health beliefs

towards influenza and influenza vaccination and their vacci-

nation behaviours. It contains six sections, where knowledge,

risk perception and vaccination behaviours scales were newly

developed. The questionnaire items were identified through

review of the literature and initial support was given for

construct validity and internal consistency reliability of each

scale.

To ensure the content validity of the instrument, expert

consultation and the pilot survey were used. There is no

criterion for the optimum number of experts but the

literature recommends that 2–20 are necessary for the content

validity process (NNSDO 2005). This study used two content

experts to review for relevance and clarity of items and the

later results of factor analyses provide evidence that the

experts captured the core content of each scale.

The construct validity analyses indicate a good fit with the

initial design of the newly developed scales of knowledge, risk

perception and vaccination behaviours scales. The knowledge

scale measures how well nurses’ have mastery of the

knowledge related to seasonal influenza and vaccination as

well as H1N1 influenza and vaccination, with the seasonal

influenza knowledge sub-scale including five dimensions (i.e.

knowledge about general information, severity, vaccination,

high-risk groups and vaccination recommended groups) and

the HK sub-scale having two dimensions (i.e. knowledge

related H1N1 and vaccination). The risk perception scale

measures how nurses feel the risk related influenza and

pandemic with three dimensions assessing nurses’ perception

to personal vulnerability to illness, negative consequences of

contracting influenza and severity of influenza respectively.

The vaccination behaviours scale measures nurses’ vaccina-

tion status and intent and vaccination recommendation to

their patients, which are defined as personal vaccination and

patient vaccination recommendation dimensions.

Although there was not an exact match with the initial

design of the seasonal influenza knowledge scale of the

instrument, the results of the factor analysis demonstrate a

relatively strong fit except for one item, i.e. A1_6 (An

epidemic can have an economic impact through lost work-

force productivity and strain on health services). This item

was initially designed together with two other items (A1_5

and A1_7) to assess nurses’ knowledge about the serious

consequences of seasonal influenza but the factor analysis

showed it to have a low factor loading and less relevance to

any potential factor. Double checking of its meaning also

suggested that its focus is on a social impact rather than a

personal level effect, thus this item was excluded from

analysis and the final analysis showed a good fit to the initial

design of this sub-scale.

The MHLC scale (Wallston 1993) was used to examine

nurses’ health locus of control. The Cronbach’s alpha

coefficients of the scale and sub-scale were 0Æ723, 0Æ652,

0Æ639 and 0Æ731, respectively showing an acceptable reliabil-

ity. This is consistent with previous testing for whole scale

with coefficients ranging from 0Æ60–0Æ75 (Wallston 2005)

and indicates that the MHLC is reliable.

Limitations

Several limitations should be kept in mind when interpreting

the results of this study. First, the test survey was conducted

with a convenience sample and therefore the findings may not

be generalisable especially to nurses not working in London

or in hospital medicine or surgery settings as the sample was

not representative of nurses working across care settings or

outside London. The extent of potential bias is unknown,

however, a large sample size with a high response rate offered

relevant valid data for the instrument testing. Further testing

with the recruitment of nurses across care settings and

outside London would provide data relating to bias. Second,

the overall knowledge scores of the participants were

remarkably low especially the HK scores and we are not

sure whether these responses have had some effects on

reliability and validity testing of the instrument. Third, the

instrument was developed as an evaluation measure among

nurses in the UK and is most suitable for this population

because it is specific to the UK healthcare system and wording

customs in British English. This might limit the application of

the instrument to other HCWs groups or nurses in other

countries without further refinement and testing.

Conclusions

This study developed and tested a multi-section instrument

which may be useful as an easy-to-use self-report measure

of nurses’ knowledge, risk perception, health beliefs

towards influenza and influenza vaccination and their

vaccination behaviours. The analyses of reliability and

validity demonstrated the strong psychometric properties of

the three the newly developed scales, namely, the knowl-

edge, risk perception and vaccination behaviours scales.

Further research using this instrument is needed to test the

tool among nurses with varying characteristics and explore

J Zhang et al.

� 2012 Blackwell Publishing Ltd

8 Journal of Clinical Nursing

the links to factors identified in this study and nurses’

vaccination behaviours.

Relevance to clinical practice

We have developed a valid and reliable instrument to assess

nurses’ knowledge, risk perception, health beliefs towards

influenza and influenza vaccination and their vaccination

behaviours. The three newly developed scales could also be

used independently to measure factors influencing nurses’

vaccination practices. The factors identified may help policy

makers and administrators understand the aspects of knowl-

edge and risk perception towards influenza and vaccination

which underpin nurses’ vaccination behaviours.

Acknowledgments

We are grateful to all the study participants and Peter Milligan

(Florence Nightingale School of Nursing and Midwifery,

King’s College London, London, UK) for his statistical advice.

Contributions

Study design: JZ, AEW, IJN; data collection and analysis: JZ,

AEW and manuscript preparation: JZ, AEW, IJN.

Conflict of interest

None declared.

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Original article Nurses’ influenza vaccination instrument

� 2012 Blackwell Publishing Ltd

Journal of Clinical Nursing 11