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Trial registered on ANZCTR


Registration number
ACTRN12616000204448
Ethics application status
Approved
Date submitted
12/02/2016
Date registered
16/02/2016
Date last updated
16/10/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Improving immunisation timeliness in infants and young children
Scientific title
A pragmatic, multi-centre, parallel design (1:1:1), open, randomised controlled trial to evaluate the effectiveness of a simple short message service (sms) vs tailored sms and home visiting compared to usual parent/carer practice to improve the uptake and timeliness of the primary immunisation series in children aged less than 2 years
Secondary ID [1] 288529 0
None
Universal Trial Number (UTN)
U1111-1179-5906
Trial acronym
PRICKLE BABES STUDY
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Vaccine Preventable Diseases 297622 0
Immunisation Delivery 297623 0
Immunisation Coverage 297624 0
Condition category
Condition code
Public Health 297810 297810 0 0
Other public health

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intervention Group A: a simple reminder sms will be sent once a fortnight starting 2 weeks before until 2 weeks following each milestone due date at 8, 16 and 24 weeks of age. All children not up to date at the 28-week timepoint will have a home visit to complete the primary series.

Intervention Group B: a tailored sms with an educational message will be sent 2 weeks before and the week of the milestone due date. Children not immunised by 2 weeks following the due date will receive a home visit. Tailoring of the message will include a personal reference reference to the parent and child, his/her vaccines due, why it is important to get the vaccines and to be on time (educational component) and information on who to contact to schedule an appoinment. Information about access to transport services will also be provided.

Adherence in both arms will be monitored by recording receipt and opening of sms messages and recording whether a response to the text message was received (response received yes or no).
Intervention code [1] 293901 0
Behaviour
Comparator / control treatment
The control group will be according to the routine pathway parents/carers following with respect to immunising their children. This may include reminders from health service providers and this will be accounted for in the analyses.
Control group
Active

Outcomes
Primary outcome [1] 297334 0
Completeness of primary immunisation series assessed by review of records on the Australian Childhood Immunisation Register and the local clinic's client database. Completeness is defined as the child having received all recommended vaccines on the National Immunisation Program (NIP) at each milestone
Timepoint [1] 297334 0
7 months of age
Primary outcome [2] 297335 0
Time to completeness (in days) of the primary immunisation series assessed by review of records on the Australian Childhood Immunisation Register and the local clinic's client database. Timeliness is defined as recommended NIP vaccines received within 30 days of the due date (calculated by birth date + 24 weeks).
Timepoint [2] 297335 0
7 months of age
Secondary outcome [1] 320754 0
Proportion of children fully immunised for age. Completeness of immunisation at each timepoint is assessed by review of records on the Australian Childhood Immunisation Register and the local clinic's client database. Completeness is defined as the child having received all recommended vaccines on the National Immunisation Program (NIP) at each milestone
Timepoint [1] 320754 0
12 and 20 weeks of age
Secondary outcome [2] 320755 0
Mean/median days to receipt from due date: Time to completeness (in days) of the primary immunisation series assessed by review of records on the Australian Childhood Immunisation Register and the local clinic's client database. Timeliness is defined as recommended NIP vaccines received within 30 days of the due date (calculated by birth date + 8 and 16weeks).
Timepoint [2] 320755 0
8 and 16 weeks of age
Secondary outcome [3] 320756 0
Direct and indirect costs of immunisation uptake and timeliness. Economic data will be collected via parent interview, review of medical records and through records kept at the study sites with respect to personnel, time and resources involved in the implementation of the study and immunisation procedures over the study duration.
Timepoint [3] 320756 0
7 months of age
Secondary outcome [4] 320757 0
Familial and child predictors of immunisation and timeliness at each milestone. These data will be collected via parental/carer interview at baseline and at 7 months of age and collection of data from the mother's and child's medical records
Timepoint [4] 320757 0
2, 4 and 6 months of age
Secondary outcome [5] 320758 0
Health service and family perspectives on immunisation delivery, uptake and interventions. These data will be collected via interview with clinic staff and study participants
Timepoint [5] 320758 0
7 months of age of the infant

Eligibility
Key inclusion criteria
(i) Mother in the 2nd or 3rd trimester of pregnancy
(ii) Not planning to move from the study area until the infant turns 8 months of age
(iii) Access to a mobile phone
(iv) Provision of written informed consent from the mother
(v) Caboolture Community Medical l or Carbal are the family’s usual health care provider.
(vii) For the RCT component, a live born infant
Minimum age
12 Years
Maximum age
45 Years
Gender
Females
Can healthy volunteers participate?
Yes
Key exclusion criteria
None will apply

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomisation codes will be computer generated by an independent biostatistician and stratified by study site. Permuted blocks of six will be used to ensure balance between groups and reduce the predictability of randomisation outcomes. Codes will be concealed in opaque envelopes that have been prepared by two personnel who will have no contact with study participants and will not be involved in any participant assessments or data collection. At the time of randomisation, staff will contact the study coordinator with the child’s and parent’s details and the next consecutive envelope in that stratum will be selected and opened to allocate the child to a study arm according to the allocation code.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation codes will be computer generated by an independent biostatistician and stratified by study site. Permuted blocks will be used to ensure balance between groups and reduce the predictability of randomisation outcomes.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Limited disclosure to participants
To reduce the potential for selection bias and differential reporting behaviours according to knowing about the potential for home-visiting for the immunisation of their infant, parents will not be informed of the detail of the RCT component of the study at enrolment. They will be informed the study will follow children to evaluate immunisation uptake and timeliness and that at various timepoints parents may receive either electronic or verbal reminders that their infant’s immunisations are due. Limited disclosure involving active concealment to participants is consistent with the NHMRC National Statement if participants will not be exposed to an increased risk of harm and a full explanation of the study aims is provided to participants at the end of the study. We are aiming to encourage parents to take the initiative with respect to vaccinating their child. If they were aware a home visit may occur, particularly for those not in the intensive intervention arm, parents may delay immunising their child until such as time as a home visit would be implemented. This would be both ethically unacceptable and pose a risk to the child.
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Sample size
Our sample size calculations were based on existing data from a cohort of children at one of the study sites that indicated 47% of children were overdue for their primary immunisation series at 7 months of age.

We are planning a three-armed study with 104 weeks accrual time and 28 weeks follow-up in the cohort. There are no existing data in this population with which inform the potential effect size we may observe. 142 children per group will be required to detect a hazard rate ratio (HRR) for failure to be age-appropriately immunised at 28 weeks of age of 1.4 in the control group compared to the intensive intervention arm with 80% power and an alpha of 0.05. Accounting for a 20% loss to follow-up over the 7 months of participation in each cohort, we will recruit 516 participants (172 per arm p).

Data Analyses
Overall cohort
Descriptive statistics will be presented for demographic, clinical, economic, risk factor and microbiological data for the study population overall, by centre and by randomisation group and expressed as proportions and/or means of the selected characteristics by proportion fully vaccinated at 24 and 72 weeks of age and mean/median time to vaccine receipt from each time point with the corresponding 95% confidence intervals (CI). Differences between groups at baseline will be assessed using t-tests for comparisons of means and chi-2 test for comparisons of proportions, conditional on test assumptions for each being satisfied. Non-normally distributed data will be analysed with appropriate non-parametric tests.

Primary objectives
Cox proportional hazards modelling will be employed to evaluate intervention effectiveness and HRRs and their corresponding 95% confidence intervals will be calculated. The primary analysis will be undertaken using a frailty model with random effects to account for recurrent events and sibling effects if applicable. The models will be fit for each immunisation milestone and overall.

SOA: Determinants of vaccine uptake and timeliness

Demographic, socio-economic, cultural, familial and health service utilisation and health service provider factors will be evaluated to determine the predictors of complete and on-time vaccination in each cohort within the models described above that incorporate time varying covariates.

SOB: Cost-effectiveness of the intervention will be determined according to established methods that incorporate individual, familial and health service provider perspectives.

SOC: Familial and health service provider knowledge and attitudes
Descriptive analyses will be performed on quantitative data collected and thematic analysis performed on narrative data collected during parent/carer and health service provider interviews.

Recruitment
Recruitment status
Stopped early
Data analysis
Data collected is being analysed
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
Other reasons/comments
Other reasons
Results of interim analysis indicated early stopping was acceptable
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 9304 0
Toowoomba Hospital - Toowoomba
Recruitment hospital [2] 9305 0
Caboolture Hospital - Caboolture
Recruitment postcode(s) [1] 17972 0
4350 - Toowoomba
Recruitment postcode(s) [2] 17973 0
4510 - Caboolture

Funding & Sponsors
Funding source category [1] 292877 0
Charities/Societies/Foundations
Name [1] 292877 0
Children's Hospital Foundation Queensland
Address [1] 292877 0
Stanley Street
South Brisbane QLD 4010
Country [1] 292877 0
Australia
Primary sponsor type
University
Name
Queensland University of Technology
Address
80 Musk Ave
Kelvin Grove, Queensland, 4059
Country
Australia
Secondary sponsor category [1] 291620 0
None
Name [1] 291620 0
Address [1] 291620 0
Country [1] 291620 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294380 0
Queensland Children's Health Services Human Research Ethics Comittee
Ethics committee address [1] 294380 0
L7 Centre for Children's Health Research
62 Graham Street
South Brisbane QLD 4101
Ethics committee country [1] 294380 0
Australia
Date submitted for ethics approval [1] 294380 0
07/03/2016
Approval date [1] 294380 0
07/04/2016
Ethics approval number [1] 294380 0

Summary
Brief summary
The uptake and timeliness of the primary immunisation series in infancy is critical to preventing infectious diseases morbidity and mortality. There is a high burden of vaccine preventable diseases in Aboriginal and Torres Strait Islander children irrespective of geographic location, however limited attention has been paid to those living in urban and regional settings. The need to improve the timeliness of the primary series has been known for at least 10 years but there has been little change over that time. Recent data from a cohort of Aboriginal and Torres Strait Islander children in Caboolture, Queensland suggests approximately 44% of children have not completed the primary series by 7 months of age. Identifying simple, culturally appropriate and cost effective interventions to improve timeliness is therefore a priority. This trial aims to To evaluate the effectiveness of targeted, culturally appropriate short messaging service (SMS) and/or home visiting in improving the uptake and timeliness of the primary immunisation series in urban/regional Aboriginal and Torres Strait Islander children
Trial website
None
Trial related presentations / publications
None
Public notes
None

Contacts
Principal investigator
Name 63506 0
Dr Kerry-Ann O'Grady
Address 63506 0
Respiratory infection Outreach and Research Team
L7, Centre for Children's Health Research
62 Graham Street
South Brisbane QLD 4010
Country 63506 0
Australia
Phone 63506 0
+61 7 3069 7270
Fax 63506 0
Email 63506 0
kerryann.ogrady@qut.edu.au
Contact person for public queries
Name 63507 0
Dr Kerry-Ann O'Grady
Address 63507 0
Respiratory infection Outreach and Research Team
L7, Centre for Children's Health Research
62 Graham Street
South Brisbane QLD 4010
Country 63507 0
Australia
Phone 63507 0
+61 7 3069 7270
Fax 63507 0
Email 63507 0
kerryann.ogrady@qut.edu.au
Contact person for scientific queries
Name 63508 0
Dr Kerry-Ann O'Grady
Address 63508 0
Respiratory infection Outreach and Research Team
L7, Centre for Children's Health Research
62 Graham Street
South Brisbane QLD 4010
Country 63508 0
Australia
Phone 63508 0
+61 7 3069 7270
Fax 63508 0
Email 63508 0
kerryann.ogrady@qut.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary