Fatal Outcome of European Tick-borne Encephalitis after Vaccine Failure

Abstract

Tick-borne encephalitis is a viral disease affecting the central nervous system. It is endemic in Switzerland with 200–250 notified cases annually. Active immunization is effective for persons in all age groups. Vaccine failure is rare, in particular after a completed vaccination course. Here, we describe the case of 67-year-old man with a fatal outcome despite vaccination. The diagnosis was confirmed by extensive postmortem analyses. The diagnostic challenges of vaccine failure in tick-borne encephalitis and the dynamics of the immune response in vaccination breakthrough are discussed.

Clinical Challenges in a 49-Year-Old Patient with Severe Tick-Borne Myeloradiculitis Despite Complete Active Vaccination

“…Thus, autoimmune conditions as a cause of LETM and viruses leading to anterior horn tractopathy including WNV and Herpes viruses needed to be excluded [16,17]. A similar observation to our CSF findings was made by the Swiss case where massive intrathecal IgM (92%) and IgG (73%) production was present [12]. In that patient, the combination of a history of a completed course of vaccination, the early serology results consistent with the vaccination and the rare incidence of vaccine failures markedly delayed the diagnosis.…”

“…Of note, the presumed protection suggested by the history of complete active vaccination should not detain from diagnostic work-up. A similar observation is mentioned in a report of a fatal TBE breakthrough case with myeloradiculitis from Switzerland [12]. The neuropathological analysis revealed a predominantly T-cell-driven parenchymal infiltration, which implicates that the vaccine-induced T-cell and antibody response failed and subsequently allowed the virus to invade the brain parenchyma and the spinal cord.…”

“…The authors explain this observation by the presence of still circulating antibodies leading to an attenuated, and therefore subclinical, viremia. Several case reports had suggested a more severe disease course in patients with vaccination failure, which could be related to advanced age [10,12,15,[18][19][20][21][22][23]. Indeed, vaccination failure is more frequent in older patients, as confirmed in the Swedish cohort, which had a median age of 62 years (range 6-83) [11].…”

Effectiveness of primary vaccination against tick-borne encephalitis in employees of the armed forces

“…The authors of previous studies have found that after a onebooster dose circulating antibodies persisted in 96-99% subjects (1,9,18). These data cannot be compared to our results, because we only analyzed the presence of antibodies after 2 and 3 doses of primary vaccination.…”

Epidemiology, clinical characteristics, diagnosis and vaccination of tick-borne encephalitis: an overview

“…Taip pat li te ra tû ro je ap ra ðo mi nuo EE vak ci nuo tø as me nø mir ties at ve jai [43]. Vy res ni pa cien tai tu ri reikð min gai maþes ná an ti kû nø kie ká [44], jiems bû din gas ma þes nis imu ninis at sa kas á vak ci nà [45].…”