Page 460 - TBE_Book_V2_2019

Chapter 14: Prevention

reported more frequently with TBE-Moscow However, investigations of the TBE-specific
vaccine; however, the differences were not neutralizing antibody titers in IVIG (intra-
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significant. venous immunoglobulin) preparations from
different geographic regions showed signifi-
A passive, post-marketing surveillance review cantly lower TBEV neutralization titers in
of EnceVir did not reveal any serious AEs up to Russian-IVIG preparations compared with
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2010. In 2010 and 2011, some lots of EnceVir European IVIG preparations.
were associated with a high incidence of fever
and allergic reactions, particularly in children Post-exposure prophylaxis with TBE vaccines
and adolescents. As a result, these lots were in persons with a tick bite has to take into
withdrawn from the market and the vaccine account the vaccination status and the
indication was restricted to adults above the incubation period of the disease. An accepted
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age of 17 years. No published safety data are approach is summarized in Table 4.
available for the Chinese TBE vaccine.

Passive Immunization TBE vaccination in
and post- exposure special patient groups
prophylaxis
Underlying medical conditions can influence

For many years, passive immunization as well the outcome of vaccination by reducing the
as post-exposure prophylaxis with TBEV IgG immune response. Alternatively, vaccination
preparations (immune globulin concentrate) can theoretically cause a deterioration or
exacerbation of the underlying condition.
was a state of the art treatment following a
Therefore, the decision to vaccinate or not in
tick bite in unvaccinated subjects in Europe
and Russia. Administration of an immuno- subjects with serious medical conditions must
globulin concentrate for passive immunization be based on a careful risk/benefit analysis.
Several studies have investigated immune
was expected to protect against disease.
response effects or influence on the course of
However, passive immunization was blamed
for antibody-mediated enhancement (ADE) of the disease in the context of TBE immuniza-
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TBE infection in children, similar to ADE tion.
phenomena in Dengue infections. In the late A controlled trial on TBE vaccination in
1990s, the use of these immunoglobulins after
patients with multiple sclerosis found no
tick exposure in a TBE-endemic area was
association between the vaccination and
discontinued even if the enhancement of disease activity (as detected by magnetic
TBEV infection could not be proven, neither in resonance imaging [MRI]), clinical relapse, or
humans nor in a mouse model. 75,76 In Russia, disease progression.
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especially in the highly endemic regions, post-
exposure prophylaxis with immunoglobulins Another study investigated the effect of TBE
continues to be common practice. Russian vaccination in medically immunosuppressed
studies report that timely administration of patients with rheumatoid arthritis. The
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specific immunoglobulin after a tick bite can patients (N=66) received a TBE primary
prevent clinical disease in about 80% of cases. immunization series while they were on
The recommended dose is 0.05 mL/kg body regular treatment with a tumor necrosis factor
weight of TBE immunoglobulin, whereby the inhibitor (TNFi) and/or methotrexate (MTX)
antibody titer should not be less than 1:80. 77,78 for at least 1 year. One month after the third

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