In short
Tick-borne encephalitis virus neudoerfl strain is the active component of an authorised vaccine used to prevent tick-borne encephalitis (TBE), a viral infection of the brain and central nervous system. The vaccine contains the inactivated whole virus and is given by intramuscular injection. One Phase 3 clinical trial with 100 participants is currently authorised to study how well the vaccine works in different groups of people.
Key points
- Phase 3 clinical trial authorised to study immune responses to the vaccine.
- Trial includes 100 participants across several groups, including patients hospitalised for TBE and healthy people starting vaccination.
- Primary outcome measures T-cell responses (cytokine release) compared with antibody responses.
- The vaccine is authorised as a medicine in Sweden under the name FSME-IMMUN Vuxen.
- It is given as a suspension for injection into the muscle.
- The trial also includes a comparator vaccine, Encepur.
What is tick-borne encephalitis virus neudoerfl strain?
Tick-borne encephalitis virus neudoerfl strain is the active substance in a vaccine against tick-borne encephalitis (TBE). The full registry name is Tick-borne encephalitis virus neudoerfl strain adsorbed on aluminium hydroxide, hydrated produced in chick embryo cells. It is a whole inactivated virus vaccine, meaning the virus has been killed so it cannot cause disease but can still trigger an immune response. The vaccine is authorised as a medicine in Sweden, where it is sold under the name FSME-IMMUN Vuxen. The authorisation holder is Pfizer AB. The virus is called an arbovirus because it is transmitted by arthropods, specifically ticks.
How does tick-borne encephalitis virus neudoerfl strain work?
The vaccine works by exposing the immune system to the inactivated tick-borne encephalitis virus. This exposure teaches the body to recognise the virus and to produce antibodies and T-cells that can fight it off if a person is later bitten by an infected tick. The new trial is measuring both T-cell responses and antibody levels to understand how the immune system responds to vaccination and to natural infection. The virus itself causes tick-borne encephalitis, a disease of the brain and central nervous system that is considered one of the most important viral infections transmitted by ticks in Europe and Asia.
Which conditions is it used or studied for?
- Tick-borne encephalitis — a viral infection of the brain and central nervous system that is spread by tick bites.
How is tick-borne encephalitis virus neudoerfl strain given?
The vaccine is given as a suspension for injection into the muscle (intramuscular injection). In the clinical trial, the vaccine is provided in a pre-filled syringe containing 0.5 millilitres of suspension. The product record also mentions a fixed combination product containing the substance.
What do the clinical trials show?
One Phase 3 clinical trial is authorised for this vaccine. The trial, called CRA-TBE, is an interventional study with 100 participants. It is measuring the magnitude and durability of T-cell responses against the tick-borne encephalitis virus using a novel rapid release assay, and comparing these with antibody responses measured by commercially available tests. The trial includes several groups: patients hospitalised for TBE, patients previously hospitalised for TBE at least 6 months before enrolment, healthy or immunosuppressed people starting vaccination, and healthy or immunosuppressed people who have already been vaccinated. The vaccine FSME-IMMUN Vuxen is the test product, while Encepur is included as a comparator vaccine. The trial is currently in the authorised status, meaning it has been approved to proceed.
What side effects are known?
Post-marketing experience with newer TBE vaccine formulations, including those without protein-derived stabilisers, shows that the majority of transient reactions after vaccination are mild. Data from eight clinical trials involving approximately 7,500 subjects aged 1 to 77 years showed the expected rate of local and systemic reactions, and pharmacovigilance data from 18 countries confirmed a high level of safety with only a common range of side effects already noted for licensed TBE vaccines. After distribution of more than five million vaccine doses, no potential safety risk was noted.