Immunizations are critically important to saving lives and protecting the health of military members and their families. Immunization science is complex, immunization products are numerous and fragile, with rigorous requirements for storage, handling, preparation, and administration. Immunization recommendations are continually evolving, and immunization recipients frequently have concerns. Despite all these challenges, immunization care is often the responsibility of junior members of the healthcare team. The organization now called the DHA Immunization Healthcare Division was established more than 20 years ago to support the critical work of immunization care. DHA Immunization Healthcare Division clinicians staff a call-in Support Center, providing continuous (24/7) access on a toll-free number (with DSN option) to immunization expertise. Call volume averages more than 1000 calls per year. Callers include immunization managers, healthcare providers, patients, and family members. Call topics cover a wide range of routine and complex questions and concerns. DHA Immunization Healthcare Division metrics demonstrate that the Support Center prevents immunization errors, and assures appropriate care for immunization concerns. Callers repeatedly verify the value of this telehealth service in supporting the critical work of immunization care throughout the Military Health System.