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Chapter 7: TBE in special situations

longer than what is seen in natural infections. In summary, based on clinical cases published,
The difference of 27 days between the two TBE is more severe in immunocompromised
recipients of kidneys might result from the patients with prolonged viral shedding and a
amount of virus in the respective donor organ. higher risk for a fatal outcome, while standard
The presence of TBE virus was confirmed by vaccination and vaccination schedules appear
real time PCR in all recipients and their donors, to be less effective.
and direct sequencing of amplification prod-
ucts showed the presence of the same viral Vaccination against TBE for HSCT patients at
strain. risk, i.e. those living in or travelling to endemic
areas, can be performed starting at 6–12
All three patients died. It remains unclear months after transplantation; however, due to
whether the differences in the clinical courses the lack of data this cannot be recommended
8
in the three patients were due to the non- as a routine procedure. The assessment of
natural transmission, the immune-suppression the immunogenicity of TBE-vaccine in patients
or both. Only one of the three patients with rheumatoid arthritis treated with tumor
showed the typical features of TBE in the necrosis factor-inhibitors (TNFi) and/or
cerebrospinal fluid, pleocytosis and increased methotrexate (MTX) was recently carried out
protein concentration. by Hertzell et al. In this study, individuals < 60
years of age were given three doses of vaccine
In another case (Dobler, personal observa- at month 0, 1, 12; individuals ≥ 60 years old
tion), a 55-year-old male patient, who had a received an additional priming dose at month
complete basic vaccination against TBE several 3, i.e. a total of four doses, while TBE neutral-
years before a liver transplantation, but was izing antibodies were assessed by a rapid
not boosted thereafter, developed a fatal form fluorescent focus inhibition test. The results
of TBE presenting with fever, encephalitis and reveal an insufficient antibody response one
tetraplegia. No information on the incubation month after a complete schedule of three or
period or on the immunosuppressive therapy four doses, compared to healthy age- and
9
was available. The patient died after 5 days of gender-matched controls.
mechanical ventilation with severe symptoms
of encephalomyelitis. A tick in his garden, In another study 29 HIV-infected patients were
which adjoined a known natural TBEV focus, vaccinated against TBE. The vaccination
had infected the patient. This case gives schedule was modified by the inclusion of a
evidence that the “natural route” of TBE- fourth dose according to the schedule 0-1-2-9
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infection may result in severe and fatal disease months. The immune response depended on
in transplant recipients. the CD4 counts of the vaccinees at the time of
vaccination. With this schedule 85% of the
In a published study including 31 heart- vaccinated persons achieved protective anti-
transplant recipients, seroconversion rates body titers. The titers persisted at least for one
and post-vaccination antibody titers were year after the third vaccine dose.
markedly reduced in comparison to the
control group, and these findings served as In summary, based on a few published clinical
evidence for recommending other protective cases, there are individual reports of patients
measures against TBE virus infection (clothing, with severe immuno-suppression (solid organ
7
avoiding high-risk areas for travel). This study transplantation) who developed TBE via the
also reported the safety of TBE-vaccination in infected organ or by tick bite. All known TBE
the above-mentioned cohort of immune- cases in transplant patients showed a fatal
suppressed patients. course.

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