In short
Dengue Virus is the active substance in Qdenga, a live attenuated tetravalent vaccine authorised in the EU for protection against dengue fever. One clinical trial, authorised but not yet started, is investigating whether Qdenga vaccination interferes with serological diagnostic tests for other flavivirus infections such as tick-borne encephalitis, yellow fever, Zika and Japanese encephalitis.
Key points
- The trial is a Phase 3 study in 45 Swedish travellers.
- The study examines whether vaccination causes cross-reactive antibodies against other flaviviruses.
- The primary outcome is IgG antibody levels against TBEV, YFV, ZIKV and JE at day 90.
- The trial is currently authorised but not yet recruiting.
- Qdenga is given as a subcutaneous injection of 0.5 ml solution.
What is dengue virus?
Dengue Virus, in the form used in Qdenga, is a live attenuated tetravalent vaccine against dengue fever. It is a fixed combination of four live attenuated dengue virus components, each representing one of the four dengue serotypes. The product is authorised as a medicine in the EU, meaning it has completed the regulatory review process and is available for use. It is supplied as a powder and solvent for solution for injection under the name Qdenga.
How does dengue virus work?
As a live attenuated vaccine, Qdenga works by exposing the immune system to weakened forms of the four dengue virus serotypes. This triggers the body to produce antibodies against dengue viruses without causing the disease itself. The vaccine is designed to generate immune protection against all four dengue serotypes, which is important because infection with one serotype does not protect against the others. The current trial investigates a specific consequence of this immune response: whether the antibodies produced after vaccination also react with related flaviviruses, which could interfere with diagnostic blood tests for those infections.
Which conditions is dengue virus used or studied for?
- Dengue fever — Qdenga is authorised as a prophylactic vaccine to protect against dengue fever caused by any of the four dengue serotypes.
- Flavivirus diagnostic interference — the current trial studies whether vaccination affects serological testing for tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), Zika virus (ZIKV) and Japanese encephalitis virus (JE).
How is dengue virus given?
Qdenga is given as a subcutaneous injection. The vaccine is supplied as a powder and solvent for solution for injection, and each dose is 0.5 millilitres. In the current trial, participants receive two doses of the vaccine.
What do the clinical trials show?
One clinical trial is registered in the EU Clinical Trials Information System for this substance. The trial is an open, non-randomised Phase 3 study that has been authorised but has not yet started. It plans to enrol 45 Swedish travellers.
What is the trial measuring?
The primary outcome is the level of IgG antibodies in serum against TBEV, YFV, ZIKV and JE at day 90 after two doses of Qdenga, compared to levels before vaccination. The study aims to assess whether the vaccine causes significantly elevated levels of cross-reactive IgG antibodies against these related flaviviruses, which could interfere with serological diagnostic tests.
What side effects are known?
The clinical trial data provided does not include information on side effects. As an authorised medicine, the product information for Qdenga contains the known side effect profile, but this is not part of the registry data supplied for this page.