Background Haemophilus influenzae type b (HIB) is a gram-negative pathogenic bacterium that mostly impacts the pediatric and geriatric population, sometimes resulting in permanent sequelae or death. Objective In this study we set out to discover adverse outcomes from the thimerosal-free HibTITER® vaccine derived from a Florida Medicaid dataset spanning from January 2003 to June 2007 ( n = 277,484). Methods HIB vaccinated children were isolated from the Florida Medicaid dataset. Using other HIB vaccines as the control, we analyzed diagnoses for statistically significant adverse outcomes related to the HibTITER® vaccine (only the strictest p-value of <0.0001 was used in analyzing this dataset). We simultaneously and independently examined the statistical significance of symptoms reported to VAERS related to HIB vaccines to corroborate our findings ( p-value significance was reported at <0.05, <0.001, and <0.0001). Results The study revealed 19 individual ICD-9 codes positively associated ( p-value<0.0001 post Bonferroni correction) with recipients of the HibTITER® vaccine within 30-days of vaccination. Of these conditions, 14 have VAERS corroborators. The diseases span severity from mild to life-threatening and areas of respiration (e.g., asthma), gastrointestinal, otolaryngologic (e.g., common cold), dermatologic, generalized infections (e.g., tuberculosis), and other conditions. Conclusion Incidence of 19 different medical conditions was significantly higher compared to the control group who received other HIB vaccine formulations. These results were corroborated using the VAERS database, and have profound medical implications for the estimated 35 million Americans between the ages of 16 and 33 who received the vaccine.