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Early connections: effectiveness of a pre-call
intervention to improve immunisation coverage
and timeliness
Felicity Goodyear-Smith MBChB, MD, FRNZCGP;1 Cameron Grant MBChB, FRACP, PhD;2 Tracey Poole;1
Helen Petousis-Harris BSc, PhD;1 Nikki Turner MBChB, MPH, FRNZCGP;1 Rafael Perera Sc, DPhil;3
Anthony Harnden MBChB, MSc, FRCGP, FRCPCH3
1
ABSTRACT
INTRODUCTION: Children who have missed or delayed immunisations are at greater risk of vaccinepreventable diseases and getting their first scheduled dose on time strongly predicts subsequent
complete immunisation. Developing a relationship with an infant’s parents and general practice staff soon
after birth followed by a systematic approach can reduce the number of delayed first immunisations.
AIM: To assess the effectiveness of a general practice–based pre-call intervention to improve immunisation timeliness.
METHODS: Clustered controlled trial of general practices in a large urban district randomised to either
delivery of pre-call intervention to all babies at aged four weeks or usual care.
Department of General
Practice and Primary Health
Care, Faculty of Medical
and Health Science, The
University of Auckland,
Auckland, New Zealand
2
Department of Paediatrics,
Faculty of Medical and Health
Science, The University of
Auckland
3
Department of Primary
Health Care, University of
Oxford, Oxford, England
RESULTS: Immunisation timeliness for infants receiving the primary series of immunisations among their
nominated Auckland general practices was higher than expected at 98% for the six week event. The
intervention was statistically but not clinically significant. Coverage was significantly lower among infants
with no nominated practice which reduced overall coverage rate for the district.
DISCUSSION: Pre-call letters with telephone follow-up are simple interventions to introduce into the
practice management system and can be easily implemented as usual standard of care. Early identification
of newborn infants, primary care engagement and effective systems including tracking of infants not enrolled in general practices has the greatest potential to improve immunisation coverage rates even further.
KEYWORDS: Randomized controlled trial; immunization; vaccination; general practice; intervention
studies
Introduction
New Zealand (NZ) historically has mediocre
immunisation coverage of children1 and relatively
high rates of vaccine-preventable disease.2 The
risk of vaccine-preventable diseases is greater if
childhood immunisations are incomplete, which
includes both missed and delayed immunisations.
Delays in immunisation puts infants at significant risk of contracting and being hospitalised for
diseases such as Haemophilus influenzae type b3–6
and pertussis4,6–9 and increases the potential reservoir of disease in unvaccinated infants.5,10
Receiving the first dose on the vaccination
schedule on time is one of the strongest and most
consistent predictors of subsequent complete immunisation11–13 and delays are significantly more
likely to result in lower overall coverage.12,14–16
In our previous study of 124 practices in the
Auckland and Midland regions of NZ, median
coverage at six weeks for the diphtheria, tetanus
and acellular pertussis immunisation was 93%,
while timely receipt of this dose was only 40%.17
Factors that impact upon immunisation receipt
and timeliness are now well established. These
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J PRIM HEALTH CARE
2012;4(3):189–198.
CORRESPONDENCE TO:
Felicity Goodyear-Smith
Professor, Department
of General Practice and
Primary Health Care,
Faculty of Medical and
Health Science, The
University of Auckland,
PB 92019 Auckland,
New Zealand
f.goodyear-smith@
auckland.ac.nz
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include the knowledge and attitudes of caregivers, particularly antenatally,18–22 attitudes of
health professionals23,24 and aspects of health care
systems such as cost, recall and reminders and
cost to provider.25
The early establishment of a relationship between
general practices and the infant’s parents can reduce the number of infants whose first immunisation is delayed.12 Our prior study demonstrated
that early enrolment with a primary care provider
was associated with a higher level of immunisation completeness.17,26,27
The NZ immunisation schedule from June 2008
for the first six months of life consisted of two
combination vaccines: INFANRIX® hexa and
Prevenar ® given at ages six weeks, three months
and five months. INFANRIX® hexa contains
antigens from diphtheria, tetanus, and pertussis (DTaP), polio, Haemophilus influenzae type b
and hepatitis B. Prevenar ® (PCV7) is a conjugate
pneumococcal vaccine that contains antigens from
seven pneumococcal serotypes that are predominant causes of invasive pneumococcal disease.28
In addition, Bacillus Calmette-Guérin (BCG) is
given to infants living in households with people
who have, or have had, tuberculosis (TB) or are
in immigrant families from countries where TB
is common, and HBvaxPRO® (hepatitis B vaccine)
is given with hepatitis B–specific immunoglobulin to newborns of mothers who are hepatitis B
carriers.
NZ practices typically have recall systems set up
in their electronic practice management systems
(PMSs) to remind parents that their child’s immunisations are overdue. All childhood scheduled immunisations should be recorded on the
National Immunisation Register (NIR) at the time
of delivery, with data directly transmitted from
the practices. The NIR sends reminder messages
to practices if information about immunisation
events is delayed. The overdue times for NIR are
set outside those for the PMS so that the practices
have time to follow up before they start receiving
overdue messages from the NIR. The PMS will
generate a recall for a child at eight weeks if the
six week doses have not been given, whereas the
NIR will consider that immunisation event overdue when the child is aged 10 weeks. Similarly,
190
PMS and NIR timeliness ‘windows’ for the three
month vaccines are aged four and four and a half
months respectively, and again for the five month
event aged six and six and a half months.
From our previous work, we hypothesised that
the enrolment of children with a general practice
soon after birth, and parents being actively invited when their baby is four weeks old to attend the
practice for their first (six week) set of vaccines,
followed up with early phone calls if they do not
respond, would improve immunisation timeliness.
We therefore aimed to conduct a randomised controlled trial (RCT) of a general practice–based precall intervention. Our objectives were to assess
the effectiveness of this enhanced practice system
on coverage and timeliness of the six week, three
month and five month immunisations.
Methods
Study design
This was an RCT of a multicomponent intervention compared with usual care. Randomisation
was at the level of the general practice. The study
was registered with Australia New Zealand
Clinical Trials Registry (00082892) and ethical approval was obtained from the Ministry of
Health Auckland Regional X Ethics Committee
(Reference NTX/08/08/072).
Setting and study population
The setting was practices in the Auckland District
Health Board (ADHB) catchment area and the
study population was babies born in the ADHB
region and/or those whose parents nominated
practices in the ADHB region as their general
practice. The study took place between 1 November 2008 and 20 April 2010. The NIR is notified
of the nominated general practice for all newborns
and the practice then is informed by the NIR that
they are the baby’s nominated practice. Children
are tracked using the unique National Health
Index (NHI) number assigned at birth.
Intervention
Our intervention consisted of a brief letter of
welcome and invitation to attend when the baby
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was six weeks, plus simple information on immunisation. This was sent by the practice to the
baby’s caregiver when the baby was four weeks
old (see appendix in the web version of this paper
for this pre-call material). A follow-up phone call
was made to the baby’s caregiver when the baby
was five weeks old if an appointment had not
already been made for the six week vaccinations
and, if the caregiver did not present the baby
for immunisation, a further attempt at contact
(early recall) was made to the caregiver when the
baby was seven weeks old. Phone calls were the
preferred method of pre-call/recall although a
text message, email or letter could also be used.
Practices were given a $15 shopping mall voucher
per baby to acknowledge the time and effort
required to administer the intervention, to be
claimed irrespective of whether or not it resulted
in immunisation of the baby.
Inclusion/exclusion criteria
and practice allocation
A database of all 148 general practices operating
in the ADHB region was created by combining
general practice databases held by the Immunisation Advisory Centre and the Department
of General Practice and Primary Health Care.
Telephone directories were cross-referenced to
ensure all practices in the ADHB region were
included. All practices were assigned a number
(practice code). Practices identified as not involved
in delivering infant immunisations were excluded. Following consent, block randomisations were
conducted of recruited practices using a computer
random number generator to assign each practice
to either the intervention or control group. The
research team other than the project manager were
blind to the identity of practices in the intervention and control groups. Intervention practices
were assisted to adjust their PMS to automatically send out pre-call and recall letters to their
patients in the study.
Outcome measures
Our primary outcome measure was receipt of
six week immunisations and age at which these
were delivered as recorded on the NIR for all the
babies in our study in intervention, control and
non-participating practices. Secondary measure-
WHAT GAP THIS FILLS
What we already know: Children who have delayed or missed immunisation events are at greater risk of vaccine-preventable diseases. Getting
their first scheduled dose on time strongly predicts subsequent complete
immunisation, and developing a relationship between the general practice
staff and a baby’s parents soon after birth can reduce the number of delayed
first immunisations.
What this study adds: Immunisation coverage and timeliness for infants
receiving the primary series of immunisations among their nominated Auckland general practices is extremely high, with no clinically relevant room for
improvement. A pre-call intervention made a statistically significant improvement in timeliness of immunisation, but only by one day. Coverage was significantly lower among infants with no nominated practice and this reduced the
overall coverage rate for a district. Targeting both the systems and services that
can identify and track infants who are not engaged with primary care at birth
has the greatest potential to improve immunisation coverage rates even further.
ments were receipt of three month and five
month immunisations and age at which these
were delivered. Pre- and post-trial surveys were
also conducted for participating practices to establish their practice population and their pre-call/
recall practices before, during and after the trial.
Power calculations
This was a clustered randomised trial with each
enrolled practice being a cluster. Because receipt
of all three primary series doses is important to
most effectively reduce risk of vaccine-preventable diseases, the trial was powered on receipt
of three month and five month immunisations.
Our previous study had shown that the inflation
effect could be between 20 and 40 (see Table 1).17
A significant contributor to this large inflation effect was the fact that at that time some
practices were not enrolling pre-school children
in their practices for pragmatic reasons which led
to a large inter-practice variability in immunisation timeliness and coverage rates. At the time of
this current study, this problem had largely been
addressed with the introduction of the NIR plus
the introduction of children being fully vaccinated by their second birthday as a performance
indicator as part of the Primary Health Organisation Performance Management Programme. With
most or all children being enrolled with practices
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Table 1. Summary of sample size calculations
Immunisation
doses
Timely immunisation coverage
Current %
Desired %
Sample size required
DE = 20
Sample size required
DE = 10
6 weeks
88
98
4000
2000
3 months
75
94
2000
1000
5 months
60
85
2000
1000
DE = Design effect
soon after birth, the design effect was expected
to be significantly smaller. We planned to
deliver 1000 interventions. This sample size was
calculated to be sufficient to have 80% power at
the 0.05 level of statistical significance to detect
an increase in the timely immunisation coverage
from 75% to 94% at the three month and from
60% to 85% at the five month immunisations.
Analysis
The variables in the NIR dataset consisted of
NHI number (converted to a unique identifier),
date of birth, dates when six week, three month
and five month immunisations given (vaccines
coded v1 for INFANRIX® hexa and v2 for Prevenar ®), nominated practice at birth, practice(s)
giving immunisation for all children born in
Figure 1. Recruitment of practices in ADHB
All general practices in ADHB
148
Eligible practices
128
Recruited
practices
63
Intervention
practices
(A) 31
192
Non-eligible practices
20
Non-recruited
practices
(C) 65
Control
practices
(B) 32
the ADHB catchment area for the study period
(1 November 2008 to 20 April 2010). At this
date all intervention babies were aged six months
or older. Immunisation events identified as BCG
vaccine were deleted.
Survival curve analysis was used to measure
delay in immunisation. For each infant participant the days from their ideal immunisation date
(i.e. 42 days for six week vaccine) to the actual
day they received vaccine were counted. For this
analysis, second and third dose assumptions
were made, i.e. if the three- and/or five month
vaccines had been given it was assumed that the
child had previously received the earlier doses.
We compared total scores (i.e. number of delayed
days) using survival analysis (Kaplan-Meier and
Cox proportional hazards) for (1) intervention
versus control group (intention to treat analysis),
(2) pre-call versus non-pre-call in the intervention group, and (3) pre-call in the intervention
group versus control group to test if there was
any significant differences. This allowed analysis
by continuous rather than dichotomous data
(i.e. defining an immunisation event as either on
time or delayed). This provided greater statistical
power and allowed for graphic representation of
results plotting number of delayed days over time
for both groups. Adjustment for clustering effect
was conducted.
Results
Practice recruitment is presented in Figure 1.
From 128 eligible practices, 63 were recruited
with 31 randomised to the intervention group
(A) and 32 to the control group (B). Groups A, B
and C (non-recruited practices) were similar with
respect to the socioeconomic status of the practice
locations and the average practice size. The num-
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Figure 2. Babies born in practice groups during the study period
ADHB
11 555 babies born
Intervention (A)
practices
2842 (24.6%) babies
Pre-call
delivered
1198 (10.4%)
babies
Control (B)
practices
2414 (20.9%) babies
Non-participating (C)
practices
5827 (50.4%) babies
No nominated
practice
472 (4.1%) babies
Pre-call not
delivered
1644 (14.2%)
babies
from the NIR in time, practice nurses stopping
the intervention for periods of time (for example during the summer period when there were
locum nurses), plus one A practice failed to deliver any interventions at all. In many instances
details were not recorded as to whether or not
the intervention included a five-week pre-call or
seven-week recall as well as the four-week precall mail-out, so sub-analyses of how often these
were required was not possible.
ber of babies born in the ADHB between 1 November 2008 and 20 April 2010 (a one year 5.75
month period) was 11 555 (see Figure 2). This is
7834 babies per calendar year, which was close
to our estimate of 8000 babies per year for the
128 eligible general practices. Half of the eligible
practices (63) were enrolled in the study, and
close to half (46%) of the babies were nominated
to these practices. There were slightly more babies born to the control (B) than the intervention
(A) practices. A small number of infants (n=472,
4%) had no nominated practice.
The overall coverage rate for the six week vaccine
‘1’ (INFANRIX® hexa) for A, B and C practices
delivered on time by eight weeks of age was
98%—see Table 2. This was also the case for
vaccine 2 (Prevenar ®). Scatter plots of the difference in timing between v1 and v2 for all cases
Only 1198 of the 2842 babies in the A practices
received pre-call interventions (42%). The reasons
for these not being delivered included practices
not receiving or being aware of the notification
Table 2. Overall vaccination rate for six week event for vaccine 1 for intervention, control, non-participating and no nominated practice
Type of
practice
Six week vaccine 1 received
by age eight weeks
Opted off /
Declined
No NIR data
Total
% completed by
practice type
A
2743
53
46
2842
97
B
2388
26
0
2414
99
C
5744
83
0
5827
99
D1
32
16
0
48
67
D2
0
0
424
424
0
10 907
177
470
11 555
% by A, B
or C only
98%
% overall
94%
Key:
A = Intervention practice
B = Control practice
C = Non-participating practice
D1 = No nominated practice, six week immunisation data available
D2 = No nominated practice, six week immunisation data not available
v1 = INFANRIX® hexa
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Figure 3. Differences in timing between vaccines 1 and 2 for six week vaccination event
and then for those in practices A and B showed
that these were rarely given separately; hence,
separate analyses for v1 and 2 were not required.
See Figure 3 for scatter plots for the six week
events which shows a straight line when time of
delivery of vaccine 1 is plotted against time of
delivery of vaccine 2.
When the 472 children with no nominated practice (D) were included in the total, the overall
vaccination rate completed by eight weeks of age
for the six week vaccination dropped from 98% to
94%. Table 3 shows the average age of receipt of
INFANRIX® hexa at six weeks, three months and
five months by practice type for children receiving immunisations. It can be seen that non-participating practices (C) consistently had a slightly
longer average delay than recruited practices (A
and B), but children without a nominated practice
who were vaccinated had a much greater average
delay. While the majority (88%) of the babies
attended the practice their parents nominated at
birth, 12% were either vaccinated or declined vaccination at a different practice for vaccine 1 at the
six week event.
We analysed data both using the second and
third dose assumptions (e.g. if the three month
dose was recorded in the NIR, we assumed the
six week event had been given) and not making
this assumption but categorising these children as
having no information on the six week vaccination
event. This made a slight difference in coverage
rates. When applied to immunisation registers, the
third-dose assumption results in an over-estimate
of immunisation coverage that is smaller than the
underestimate produced by assuming all those
with missing data have not been immunised.29
When the vaccination times of A and B practices
for receipt of the six week vaccine were compared (intention-to-treat analysis), there was no
indication of a difference between the groups
(Log Rank (Mantel-Cox): Chi-square 0.268, df=1,
p=0.605). There also was no difference in days
to vaccination for the three month vaccine event
(Log Rank (Mantel-Cox): Chi-square 0.540, df=1,
p=0.46) nor for the five month vaccine (Log Rank
(Mantel-Cox): Chi-square 0.281, df=1, p=0.60).
Table 3. Average age of receipt of INFANRIX® hexa at six weeks, three months and five months by practice type
Practice
type
Average age in weeks of
receiving six week v1
Average age in months of
receiving three month v1
Average age in months of
receiving five month v1
A
7.06
3.40
5.64
B
7.09
3.43
5.65
C
7.26
3.48
5.7
D
8.92
4.49
6.32
Key:
A = Intervention practice
B = Control practice
C = Non-participating practice
D = No nominated practice
v1 = INFANRIX® hexa
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However, this analysis did not take into consideration the fact that the 58% of children in the A
practices did not receive the intervention.
We therefore conducted a second analysis looking
at vaccination in group A, stratifying by actual
delivery of the intervention. This showed that
babies receiving the intervention were statistically more likely to receive their six week vaccination event earlier (Log Rank (Mantel-Cox):
Chi-square 19.187, df=1, p<0.001) with mean
days to six week vaccination event 49.6 days
for those who received interventions compared
with 51.2 days for those who did not—see
Figure 4. An advantage of this analysis is that
it takes into account types of censored data, for
example where six week data is missing but the
third dose assumption is used. The same pattern
was repeated for vaccination coverage stratified
by delivery of intervention for A practices for
the three month vaccination event (Log Rank
(Mantel-Cox): Chi-square 16.527, df=1, p<0.001)
with mean days 100.1 compared with 103.8, and
for the five month event (Log Rank (Mantel-Cox):
Chi-square 11.621, df=1, p=0.001) with mean
days 166.2 compared with 170.1.
A third analysis comparing only those babies in
the A practices who had received the intervention with the group B babies found a similarly
significant result for the six week vaccination
event results (Log Rank (Mantel-Cox): Chi-square
5.969, df=1, p=0.015), the three month (Log
Rank (Mantel-Cox): Chi-square 10.722, df=1,
p=0.001) and the five month (Log Rank (MantelCox): Chi-square 6.753, df=1, p=0.009).
While there was no statistical difference in
timeliness between A and B groups, we expected
that recruited practices (A and B) would have less
delay in immunisation overall than C practices
which declined to participate (and may be less focused on vaccination). We therefore repeated the
timeliness analysis including group C for the six
week vaccine. We found that group C practices
had a significantly more delayed vaccine rate for
the six week vaccine (Log Rank (Mantel-Cox):
Chi-square 14.705, df=1, p=0.001).
Lastly, analysis of practice surveys found that
13 A and 12 B practices used some form of
pre-call prior to the trial. All but one A practice
(which had failed to use the pre-call intervention)
intended to continue using our pre-call intervention post-trial.
Discussion
At the commencement of our study in 2008, NZ
immunisation rates were estimated from the NIR
data to be 88% for the six week vaccine event,
75% for the three month event and 60% for the
Figure 4. Days to six week vaccination event in Group A stratifying by actual delivery of the intervention
Comparison of time to vaccination comparing intervention delivered or
not delivered
Log of comparison of time to vaccination comparing intervention
delivered or not delivered to demonstrate differences
The window for ‘timely’ six week vaccination is 6–10 weeks (42–70 days)
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five month event. We calculated our sample size
based on these data. However, we found the coverage rate for enrolled children in all practices in
the study was much higher than expected, at 98%
for the six week vaccine and dropped off very little for the three month and five month doses.
We did find a statistically significant improvement in timeliness of vaccine receipt at the
six week, three month and five month events
comparing children who received the intervention
with those who had not, but because the coverage rates were so high, this only translated into
children receiving the vaccine on average one day
earlier (from 49.5 days to 50.5 days for the vaccine
due at 42 days), which is not clinically significant.
Given that there were much higher coverage rates
across all practices to start with, the lack of clinical significance is not surprising.
While the average coverage among all the ADHB
practices was 98%, there was a small percentage of
infants without nominated practices (n=472, 4%).
Thirty-three percent of infants with no nominated practice for whom there was an entry for the
six week vaccination event were not vaccinated.
When these infants were added to the total, the
overall coverage rate dropped to 94%. This is an
important finding. Infants with no nominated
general practices are much less likely to get immunised and, if they do, are much more likely to
be delayed. This reduces the overall coverage rate
significantly for the region (making the general
practices look as though they are performing less
well than they are). Children who are not getting
general practice services including immunisation pre-call and/or recall can be considered to be
‘falling through the cracks’: Attention needs to be
given to this group of children, both encouraging
earlier general practice enrolment for them and
targeting outreach services for those unenrolled.
We identified a number of places where errors
occur in the collection of data in the NIR: the
practitioner (usually the practice nurse) may enter
incorrect data in the PMS, there may be technical problems with the transfer of data from the
PMS to the NIR, the NIR might send back error
messages to the practitioners’ inboxes that they
do not know how to action, a practitioner may not
196
know how to manage entry of complex ‘catchup’ schedules when a child is presenting late or
has received a different immunisation regime in
another country, or the PMS might not have the
facility to record these complex immunisation
entries accurately. An unvaccinated child presenting at three months may have this immunisation
event recorded as the three month rather than the
six week vaccination event. Furthermore when
patients transfer practices it is usually not possible
for their full clinical records to be transferred
electronically between practices. This means that
the new practice needs to manually enter previous vaccines from paper records or the child well
health book, which will not always be available.
How our findings relate to
what is already known
Timeliness of children’s vaccination varies
widely between and within countries.30–39 There
are a range of factors associated with timeliness reported in these studies. Ethnicity, area of
residence21,40,41 and negative media coverage are all
associated with delay in vaccination.36
Integrated systems including outreach and recall
has been shown to be effective. For example, an
extensive programme in Chicago which combined
immunisation education at birth with ongoing
reminder–recall achieved over 90% on-time adherence for recommended immunisations among
inner-city children aged 0–35 months.42 Having
a nurse vaccine manager who is in charge of
tracking inventory, training staff, and developing
vaccination protocols can improve timeliness of
vaccine delivery.43
Our study shows that enrolment and early
engagement with a general practice is resulting in
excellent coverage and timeliness. However the
children not enrolled with a general practice fare
poorly and represent a small but significant group
for whom outreach services should be targeted,
and assistance given for the infant to join a general practice.
Strengths and limitations
We piloted the intervention set-up, received early
datasets for testing, performed dummy runs, dou-
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ble-entered data and performed meticulous data
cleaning to ensure we had an accurate dataset to
analyse.
However, we recruited fewer practices to the
study (63/128, 50%) than the 60% we had
intended and we had delays in some practices
implementing the intervention. The intervention was only delivered to 42% of the eligible
children in the intervention practices, plus some
of the practices reported that they were already
doing some form of recall; hence, the comparison
between intervention and control group had no
significant difference. We had incomplete records
of whether or not the delivered intervention
included five-week pre-call or seven-week recall
contacts.
Recommendations
As a result of this study we recommend that NIR
notify general practices so that they are aware of
all newborns for whom the practice is the nominated provider as soon as possible after birth, and
that DHBs follow up newborns with no nominated providers to ensure registration with a provider
as early as possible. Different regions will use
different strategies to achieve this. We further
recommend that practices send a pre-call letter
with accompanying information about immunisation when infants are aged four weeks, as a fully
automated prompt system followed by telephone
contact if the family does not make contact seems
to be a cost-efficient and sensible strategy. Because
many Auckland practices are already doing some
form of pre-call, having a standardised four-week
pre-call letter prompt system that all practices
could use may have a positive effect on timeliness. It could assist those practices who are not
pre-calling and act as a reaffirmation to those
practices who are pre-calling that their current
commitment is worthy of continuing.
Conclusion
We found immunisation coverage and timeliness for infants receiving the primary series of
immunisations among their nominated Auckland
general practices to be extremely high, with no
clinically relevant room for significant improvement. The intervention trialled in this study
made a statistically significant improvement to
timeliness of vaccination; however, only by one
day. However, coverage was significantly lower
among infants with no nominated practice and
this reduced the overall coverage rate. Non-enrolment of babies at birth with a general practice is a
significant factor in delayed or missed immunisations. Targeting both the systems and services
that can identify and track these infants has the
greatest potential to improve immunisation coverage rates even further.
References
1. Ministry of Health. The National Childhood Immunisation
Coverage Survey 2005. Wellington; 2007.
2. Ministry of Health. Immunisation handbook 2006. Wellington:
Ministry of Health; 2006.
3. Grant C, Roberts M, Scragg R, Stewart J, Lennon D, Kivell
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Commun Dis NZ. 1991;91(9):88–9.
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its relationship to preventive health care visits among innercity children in Baltimore. Pediatrics. 1994;94(1):53–8.
13. Williams IT, Milton JD, Farrell JB, Graham NM. Interaction of
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of immunization coverage in Virginia children. Pediatrics.
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197
ORIGINAL SCIENTIFIC PAPERS
QUANTITATIVE RESEARCH
ACKNOWLEDGEMENTS
Thanks to the general
practices involved in the
study for their valuable
cooperation and assistance
in making this study
possible and, in particular,
the practice nurses precalling the children at the
intervention practices.
We appreciate the
valuable advice provided
to us by our Stakeholder
Advisory Board on design
and delivery of the
intervention. Thanks also
to Mr Charles Misquitta
and Ms Janine Peters at
Auckland District Health
Board (ADHB) for their
assistance with the ADHB
National Immunisation
Register (NIR), Mr Mishra
Suryaprakash at the
Ministry of Health (MoH)
for communication with
the National Immunisation
Register Governance
Group, members of the
NIR Governance Group
for approving this study,
Rachel Guthrie, Population
Event Registers Team
Lead, MoH, for assistance
with accessing NIR
data, Deirdre McMahon
and Dipan Ranchhod
(Data Quality Analyst),
National Collections Data
Management Sector
Services, MoH, for
assistance with NIR data,
and to Dr Lynn Taylor,
Operations Manager of
IMAC for information on
potential errors occurring
between practice and
NIR messaging.
FUNDING
This study was funded
by the Health Research
Council of New Zealand
and the Ministry of Health.
COMPETING INTERESTS
None declared.
198
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ORIGINAL SCIENTIFIC PAPERS
QUANTITATIVE RESEARCH: APPENDIX
APPENDIX A: Pre-call material
A pre-call letter and information sheet about immunisation was generated by the PMS for fourweek-old babies. These were printed on white A5 paper using the practice nurse’s standard paper and
printer.
Pre-call letter
Dear [name of caregiver],
We would like to welcome your new baby to our practice.
As our babies grow, immunisation is part of the regular care that they are offered. It is nearly time for
your baby’s first immunisations which are due at six weeks of age.
Having your baby immunised on time is important and offers protection against seven serious diseases
early on. Enclosed you will find some brief information about the six week immunisations. Scheduled
childhood immunisations are free for all New Zealand children.
Please contact us at the practice to arrange a time to come in. We look forward to meeting you and
your baby.
Kind Regards,
[Practice contact]
Information about vaccines at six weeks
Getting your baby immunised on time at six weeks will reduce the chance of contracting vaccinepreventable diseases. Starting on time is important because young babies are particularly at risk of
catching these diseases.
At six weeks, two injections are offered to provide protection against seven serious diseases. One injection called INFANRIX® hexa and one called Prevenar ® start the important process of protecting your
baby against diphtheria, tetanus, whooping cough (pertussis), polio, hepatitis B, Haemophilius influenzae type b, meningitis and pneumococcal disease.
As with any health procedure, there are risks and benefits. If you have any questions, please talk with
your GP or practice nurse or call 0800 IMMUNE (466863). More detailed information about the immunisations your baby will be offered and the diseases the vaccines protect against can be found at
http://www.immune.org.nz/.
VOLUME 4 • NUMBER 3 • SEPTEMBER 2012 J OURNAL OF PRIMARY HEALTH CARE
A1—WEB VERSION ONLY
Helen Petousis-harris