To report a case of severe tick-borne myeloradiculitis despite vaccination against the disease.

While the vaccination rate against tick-borne encephalitis virus (TBEV) in the Austrian population is  the highest worldwide, an increasing number of cases have been reported recently. Amongst are cases of vaccination failure, which have a more severe disease course and delay in diagnostic work-up according to recent clinical reports.

A 49-year-old woman was admitted to our department due to intractable lower back pain and a mild paresis of the right leg, which had developed over the course of four days. Three days later, she developed voiding dysfunction, paresis of the left arm and paraplegia of the lower extremities. There were a couple of non-enhancing white matter lesions on brain MRI and spinal cord MRI visualized a myelopathy extending from the cervical to thoracic spinal cord. CSF diagnostics revealed mild pleocytosis and elevated protein levels. PCR testing for Herpes viruses were negative. Serological tests were thus directed towards neuromyelitis spectrum disorders, CNS manifestations of systemic autoimmune disorders and other causes of longitudinally extensive transverse myelitis. Without any evidence for these conditions, extended work-up eventually corroborated myeloradiculitis due to TBEV despite a history of immunization with regular refresh courses. On clinical examination two years later she still a mild lower extremity paraparesis whereas the urinary dysfunction and pain had fully recovered.  

TBEV cases as a consequence of vaccination failure are increasingly recognized and could be related to a decrease of the immunological response with age. This is also reflected by a report showing that 70% of the TBEV vaccination failures occur in patients above the age of 50 years. Thus, diagnostic testing should not be withheld in patients with known immunization courses and translation of concepts for more effective vaccination in the elderly population are eagerly awaited.