DENGUE VIRUS, SEROTYPE 2, EXPRESSING DENGUE VIRUS, SEROTYPE 1, SURFACE PROTEINS, LIVE, ATTENUATED

Table of contents

• What is dengue virus?
• How does dengue virus work?
• Which conditions is it used or studied for?
• How is dengue virus given?
• What do the clinical trials show?
• What side effects are known?

What is dengue virus?

DENGUE VIRUS, SEROTYPE 2, EXPRESSING DENGUE VIRUS, SEROTYPE 1, SURFACE PROTEINS, LIVE, ATTENUATED is a live, attenuated tetravalent vaccine against dengue fever, marketed under the name Qdenga.^[1] It is classified as a vaccine and is already authorised as a medicine in the European Union, with the marketing authorisation held by Takeda GmbH.^[1] The vaccine contains four components based on a dengue virus serotype 2 backbone: the attenuated serotype 2 virus itself, plus three modified versions expressing surface proteins of dengue virus serotypes 1, 3, and 4.^[2]

How does dengue virus work?

The vaccine works by exposing the immune system to weakened forms of all four dengue virus serotypes. Because the viruses are attenuated, they cannot cause dengue disease but still trigger an immune response. The serotype 2 backbone expressing surface proteins from the other three serotypes allows a single vaccine to generate antibodies against all four dengue virus types.^[2] This is important because infection with one dengue serotype does not protect against the others, and a second infection with a different serotype can be more severe.

Which conditions is it used or studied for?

• Prevention of dengue fever — the vaccine is authorised for this indication and is being studied in travellers.^[1][2]
• Cross-reactivity in flavivirus diagnostics — the registered trial investigates whether vaccination interferes with serological tests for other flavivirus infections such as tick-borne encephalitis, yellow fever, Zika, and Japanese encephalitis.^[1]

How is dengue virus given?

The vaccine is given as a subcutaneous injection. The pharmaceutical form is a powder and solvent for solution for injection, and each dose is 0.5 ml.^[1] A pre-filled syringe formulation is also referenced in regulatory documents.^[2]

What do the clinical trials show?

One interventional trial is registered for this substance in the EU Clinical Trials Information System. It is an open, non-randomised phase 3 trial that is currently authorised and enrolling 45 participants.^[1] The trial enrols healthy Swedish travellers who are planning to receive the Qdenga vaccine before travel to dengue-endemic areas. The primary outcome measures IgG antibody levels in serum against tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), Zika virus (ZIKV), and Japanese encephalitis virus (JE) at day 90 after two doses of Qdenga, compared to antibody levels before vaccination.^[1] The aim is to determine whether vaccination causes elevated levels of cross-reactive antibodies that could interfere with serological diagnostics for these related flavivirus infections.^[1]

What side effects are known?

The available sources do not provide detailed side effect information for this vaccine.