Bologheanu et al.
Unexpected complete recovery of a patient with severe tick-borne encephalitis treated with favipiravir
Antiviral Res. 2020; 184:104952,

This publication is dealing with antiviral treatment of a TBE patient with a non-licensed drug.

A 22-year-old male suffered from severe TBE despite primary immunization and regularly administered booster vaccinations. Empirical therapy with acyclovir and ceftriaxone, and symptomatic treatment were initiated. However, during the next few days, the patient became unresponsive and was transferred, already endotracheal intubated, to an intensive care unit. Based on the clinical presentation, West Nile virus (WNV) infection was suspected and treatment with favipiravir was initiated, which has demonstrated efficacy against WNV infection in rodents. The patient received 1600 mg favipiravir twice a day, followed by 600 mg twice daily for seven days. Then, demonstration of IgM and IgG, specific for TBE virus in CSF, was detected and WNV infection was excluded, and therapy with favipiravir was continued. On day 7 of antiviral treatment, almost complete resolution of signal abnormalities was observed. By discharge 14 days after symptom onset, the patient had completely recovered.

Interpretation of the antiviral capacity of favipiravir for therapy of TBE is difficult. Yet, favipiravir is a potent inhibitor of the RNA-dependent RNA polymerase and its efficacy against other flaviviruses has been proven.

Further clinical research on anti TBE virus compounds is warranted.

Some drugs which are FDA approved for antiviral treatment, also show anti-flavivirus specific activity or even anti-TBE virus activity (see Snapshot week 22/2020). Recently, novel anti TBE virus uridine glycoconjugates have been tested, which look promising in in-vitro anti-TBE virus tests (Brzuska et al, Pharmaceuticals. 2020; 13:460, doi:10.3390/ph13120460).

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