Using Synthetic Data for Machine Learning-based Childhood Vaccination Prediction in Narok, Kenya
Authors: Jimmy Bach, Yang Li, Yaqi Liu, John Sankok, Rose Kimani, Carrie B. Dolan, Julius N. Odhiambo, Haipeng Chen
Organizations: William & Mary Williamsburg, VA, United States · Ignite Global Health Research Lab, William & Mary Global Research Institute Williamsburg, VA, USA · William & Mary Department Williamsburg, VA, USA · Data-Driven Decision Intelligence Lab (D3i) Williamsburg, VA, USA · Community Health Partners Narok, Kenya · William & Mary Health Sciences Williamsburg, VA, USA · William & Mary Department of Data Science Williamsburg, VA, USA
Background: Limited data utilization in low-resource settings poses a barrier to the vaccine delivery ecosystem, undermining efforts to achieve equitable immunization coverage. In nomadic populations, individuals face an increased risk of missing crucial vaccination doses as children. One such population is the Maasai in Narok County, Kenya, where the absence of high-volume, quality data hampers accurate coverage estimates, impedes efficient resource allocation, and weakens the ability to deliver timely interventions. Additionally, data privacy concerns are heightened in groups with limited sensitive data. Objectives: First, we aim to identify children at risk of missing key vaccines across a large population to provide timely, evidence-based interventions that support increased vaccination coverage. Second, we aim to better protect the privacy of sensitive health data in a vulnerable population. Methods: We digitized 8 years of child vaccination records from the MOH 510 registry (n=6,913) and applied machine learning models (Logistic Regression and XGBoost) to identify children at risk. Additionally, we utilize a novel approach to tabular diffusion-based synthetic data generation (TabSyn) to protect patient privacy within the models. Results: Our findings show that classification techniques can reliably and successfully predict children at risk of missing a vaccine, with recall, precision, and F1-scores exceeding 90% for some vaccines modeled. Additionally, training these models with synthetic data rather than real data, thus preserving the privacy of individuals within the original dataset, does not lead to a loss in predictive performance. Conclusion: These results support the use of synthetic data implementation in health informatics strategies for clinics with limited digital infrastructure, enabling privacy-preserving, scalable forecasting for childhood immunization coverage.
Figures & tables
Figure 1. Data Preprocessing Steps
Variable
Categorical Value
Overall
n
6912
Age (yrs), mean (SD)
3.3 (2.1)
First Visit Day, mean (SD)
24.9 (55.2)
Gender, n (%)
Female
3396 (49.1)
Male
3516 (50.9)
Clinic, n (%)
Aitong
1523 (22.0)
Table 1. Summary Statistics of the Study Population
Figure 2. Number of Individuals Within Each Clinic Registry
Figure 3. Distances Traveled by Individuals to the Nearest Health Facility
Vaccine
n = 6913, No / Yes (%)
BCG
301 (4.4) / 6612 (95.6)
POLIO
3310 (47.9) / 3603 (52.1)
OPV1
1476 (21.4) / 5437 (78.6)
OPV2
2177 (31.5) / 4736 (68.5)
OPV3
2894 (41.9) / 4019 (58.1)
IPV
3208 (46.4) / 3705 (53.6)
Table 2. Outcome Distribution for Different Vaccines
Logistic Regression
XGBoost
Vaccine
Training Split
F1
Precision
Recall
F1
Precision
Recall
BCG
Real
0.8348
0.9203
0.7921
0.8853
0.9239
0.863
BCG
Synthetic
0.8334 ± 0.0193
0.9198 ± 0.0012
0.7909 ± 0.0245
0.8866 ± 0.0065
0.9173 ± 0.0015
0.867 ± 0.0102
BCG
Real + Synthetic
0.8234 ± 0.0089
0.9209 ± 0.0011
0.7776 ± 0.0114
0.8807 ± 0.0051
0.9255 ± 0.011
0.857 ± 0.0073
ROTA2
Real
0.746
0.7485
0.7484
0.7501
0.7505
0.7513
ROTA2
Synthetic
0.745 ± 0.006
0.7482 ± 0.0059
0.7478 ± 0.0059
0.7391 ± 0.0067
0.7401 ± 0.0068
0.7412 ± 0.0067
Table 3. Comparison of ML Model Performance (Mean ± Standard Deviation) across Iterations of Synthetic Data.
Column
BCG
DPT3
MR1
All Vaccines
clinic
0.9866 ± 0.0026
0.9854 ± 0.0037
0.9898 ± 0.0045
0.9888 ± 0.0044
age
0.9607 ± 0.0035
0.9716 ± 0.0050
0.9610 ± 0.0053
0.9628 ± 0.0097
gender
0.9919 ± 0.0042
0.9010 ± 0.0067
0.9536 ± 0.0132
0.9833 ± 0.0236
village
0.9457 ± 0.0035
0.9428 ± 0.0043
0.9637 ± 0.0031
0.9529 ± 0.0086
first visit day
0.9876 ± 0.0036
0.9797 ± 0.0034
0.9866 ± 0.0043
0.9846 ± 0.0046
vax
0.9975 ± 0.0027
0.9971 ± 0.0024
0.9945 ± 0.0047
0.9953 ± 0.0034
Table 4. Comparison of Column-Wise Density (Mean ± Standard Deviation) across Vaccines.
Column Pairs
BCG
DPT3
MR1
All Vaccines
clinic/age
0.9347 ± 0.0045
0.9140 ± 0.0068
0.9195 ± 0.0050
0.9244 ± 0.0167
clinic/gender
0.9826 ± 0.0024
0.9003 ± 0.0064
0.9523 ± 0.0114
0.9732 ± 0.0210
clinic/village
0.9246 ± 0.0021
0.9274 ± 0.0049
0.9531 ± 0.0036
0.9392 ± 0.0143
clinic/first visit day
0.9803 ± 0.0018
0.9777 ± 0.0029
0.9820 ± 0.0056
0.9819 ± 0.0043
clinic/vax
0.9835 ± 0.0022
0.9684 ± 0.0058
0.9812 ± 0.0032
0.9803 ± 0.0060
age/gender
0.9574 ± 0.0034
0.8989 ± 0.0049
0.9423 ± 0.0054
0.9532 ± 0.0165
Table 5. Comparison of Pair-Wise Column Correlation Scores (Mean ± Standard Deviation) across Vaccines.
Figure 4. Feature Importance Analysis: DPT3 Real Data
Figure 5. Feature Importance Analysis: DPT3 Synthetic Data