Medicine is experiencing a paradigm shift, where patients are increasingly involved in the management of their health data. We created a mobile app which permitted parental reporting of immunization status to public health authorities. We describe app use as a proxy for feasibility and acceptability as well as data utility for public health surveillance. The evaluation period ran from April 27, 2015, to April 18, 2017, during which time 2,653 unique children's records were transmitted, containing 36,105 vaccinations. Our findings suggest that mobile immunization reporting is feasible and may be an acceptable complement to existing reporting methods. Measures of data utility suggest that mobile reporting could enable more accurate assessments of vaccine coverage.