Social support of low-income Brazilian mothers related to time to completion of childhood vaccinations.

Our study objective was to examine how maternal social support and depressive symptoms are associated with time to completion of childhood vaccinations. We used cross-sectional data from 582 randomly-selected, low-income Brazilian children. Adjusted Cox Proportional Hazard models were used to estimate time to completing the first three recommended oral polio and diphtheria, pertussis and tetanus (DPT) vaccinations as well as their booster doses. Among only the women with low social support, each ten-point increase on the Medical Outcomes Study - Social Support Scale was associated with a 20% increased chance of completing the first three recommended vaccinations for polio and DPT at any given time (HR = 1.20, 95% CI 1.02-1.42). Although falling short of statistical significance, also among mothers with low social support, we found a suggestive finding of increased social support associated with 25% greater chance of completing polio and DPT booster vaccines at any given time (HR = 1.25, 95% CI 0.98-1.60). There was no association between maternal depressive symptoms and vaccination completion. Among mothers with little social support, increased social support may be important for timely completion of vaccinations in low-income Brazilian children. Longitudinal studies and research on mechanisms explaining associations between maternal social support and childhood vaccination are needed.