Health Psychology - Cardiff University

4 PAYAPROM, BENNETT, ALABASTER, AND TANTIPONG
year’s (2009) vaccination program, and provided information
about the symptoms of influenza, brief details about the flu vaccine,
possible side effects following vaccination, and the general
benefits of influenza vaccination, including “flu shots help prevent
the flu and its serious complications.” No details about the complications
of the flu and other benefits of influenza vaccination
were addressed. Accordingly, the key techniques in this leaflet
were to provide information about the behavior-health link and the
consequences of vaccination (Abraham & Michie, 2008). An appointment
letter detailing a date and time of vaccination was also
sent to all high-risk individuals.
Questionnaires
The questionnaires assessed changes on key HAPA variables. In
addition, as information about influenza and the influenza vaccine
formed an important element of the leaflet, questions related to
influenza symptoms and vaccine side effects were also included.
With the exception of three questions addressing planning, asked
only at T2, the same questionnaire was given to participants at T1
and T2. A draft questionnaire was pilot tested by 20 Thai adults.
Knowledge
Knowledge of influenza symptoms and vaccine side effects
were assessed by presenting participants with a list of 13 symptoms
(e.g., fever, watery eyes) and eight potential vaccine side
effects (e.g., pain at the vaccination spot, vomiting). There were
eight correct influenza symptoms and four correct vaccine side
effects. Participants were asked to tick yes, no, or not sure, to
the symptom and vaccine side effects checklist.
Risk Perception
For the measure of risk perception, participants were asked to
indicate their level of agreement or disagreement with 15 statements
referring to (i) the risk of developing influenza and (ii) the
consequences of influenza to their lives (e.g., “If someone in my
family develops flu, everyone else will,” and “Flu can make my
existing illness worse”). Items were measured using a 5-point
Likert scale from 1 (strongly disagree) to5(strongly agree). Total
risk perception scores, ranging from 15 to 75, were calculated by
summing the item scores. In addition, separate risk (Cronbach’s
T1 0.79; T2 0.68) and consequence subscales (Cronbach’s
T1 0.75; T2 0.70) were derived.
Outcome Expectancies
Outcome expectations after receiving the vaccine were assessed
with seven items, including “If I get the flu shot it can prevent me
from getting a more severe case of the flu,” and “If I get the flu
shot it will help me stay healthy during the flu season.” All items
were rated on a 4-point Likert scale from 1 (not at all true) to4
(exactly true). Item scores were summed to provide a total outcome
expectancy score, ranging from 7 to 28 (Cronbach’s alpha
T1 .72; T2 0.81).
Self-Efficacy
Self-efficacy was measured by asking participants to rate their
level of confidence in their ability to obtain and cope with the
influenza vaccine in the next vaccination period. The scale comprised
seven items, including “I am confident that I can cope with
side effects after receiving the flu vaccine,” and “I am confident
that I can find the time to get vaccinated against the flu.” Responses
were reported on a 4-point Likert scale from 1 (not at all
true) to4(exactly true). Two self-efficacy subscales were derived:
self-efficacy in coping with vaccine side effects (Cronbach’s
T1 0.72; T2 0.81) and self-efficacy for arranging time and
transportation (Cronbach’s alpha T1 0.84; T2 0.91).
Intention
Participants indicated their level of intention to obtain influenza
vaccination with two statements: “I intend to receive a flu shot in
the forthcoming vaccination period,” and “I want to get vaccinated
against the flu in the next vaccination period.” Answers were given
on a 5-point scale from 1 (definitely do not) to5(definitely do).
These items were added to form a sum score of intention, with total
scores ranging from 2 to 10 (Pearson’s r T1 0.61; T2 0.67).
Action Planning (T2 Only)
Action planning was measured by responses to three questions:
“I have made a plan when I’m going to vaccinate during the next
vaccination period,” “I have made a plan where I’m going to have
the flu shot in the next vaccination period,” and “I have made a
plan how I’m going to get vaccinated against the flu.” The response
alternatives were “Yes” and “No.” Participants in the
HAPA intervention were also required to bring the leaflet to the
researcher at the T2 data collection in order to verify whether they
had made an action plan. Participants were scored as either completing
the planning process (all three issues were addressed) or
not completing the process (two or less issues were addressed).
Procedure
Potential participants in both the intervention and comparison
areas were approached by village health volunteers who gave them
an invitation letter together with a reply slip, indicating their
willingness to consider participating in the study. Those who
agreed to consider participation were then visited by a research
assistant, either in their home or at a health center. At this meeting,
participants were given more information about the study and
signed a consent form before completing the baseline questionnaire.
If participants had limited literacy, the researcher read the
statements or questions out loud and asked participants to score
their own responses.
After T1 data collection was completed, leaflets enclosed in a
plain brown envelope were distributed to participants by the village
health volunteers. The HAPA intervention participants received
a HAPA-based educational leaflet. The comparison group
received a standard influenza leaflet developed by the Ministry of
Public Health. Two weeks later, participants were again approached
by research assistant, and asked to complete the T2
questionnaires and to show their leaflets verifying their use the
implementation intention intervention.
Data Analysis
Analyses were performed on an intention-to-treat basis. Baseline
characteristics of participants in the intervention and compar-