Dengue virus, serotype 2, live, attenuated

Table of contents

• What is dengue virus, serotype 2, live, attenuated?
• How does dengue virus, serotype 2, live, attenuated work?
• Which conditions is it used or studied for?
• How is dengue virus, serotype 2, live, attenuated given?
• What do the clinical trials show?
• What side effects are known?

What is dengue virus, serotype 2, live, attenuated?

Dengue virus, serotype 2, live, attenuated is one of four weakened (attenuated) dengue virus strains contained in the vaccine Qdenga. The full registry name for the vaccine lists all four components: dengue virus serotype 2, live, attenuated, acting as the backbone, with genes for surface proteins from dengue virus serotypes 1, 3 and 4 engineered into it.^[1] Qdenga is a dengue tetravalent vaccine (live, attenuated), authorised as a medicine in the European Union under authorisation record EU/1/22/1699/001, held by Takeda GmbH.^[1] The vaccine contains genetically modified organisms and is produced in Vero cells by recombinant DNA technology.^[2]

How does dengue virus, serotype 2, live, attenuated work?

Qdenga stimulates the body's natural defences, the immune system, so that it can help protect against the viruses that cause dengue if the body is exposed to them in the future.^[3] Because the vaccine contains weakened versions of all four dengue virus serotypes, it cannot cause dengue disease itself.^[3] The serotype 2 strain serves as the genetic backbone into which surface protein genes from the other three serotypes are inserted, so that one vaccine can generate immune responses against all four types of dengue virus.^[2]

Which conditions is it used or studied for?

• Prevention of dengue disease — Qdenga is authorised for the prevention of dengue disease in individuals from 6 years of age.^[2]
• No medical condition (healthy volunteers) — the registered trial in Sweden is being conducted in healthy travellers, not in people who are ill, to study how vaccination affects antibody tests for other flaviviruses.^[1]

How is dengue virus, serotype 2, live, attenuated given?

Qdenga is supplied as a powder and solvent for solution for injection. After reconstitution, one dose of 0.5 mL contains at least 2.7 log10 plaque-forming units of the live, attenuated dengue virus serotype 2 component.^[2] The vaccine is given by subcutaneous injection, preferably in the upper arm in the region of the deltoid muscle. It must not be injected into a blood vessel, into the skin, or into a muscle.^[2] The recommended schedule is a 0.5 mL dose at a two-dose schedule, with the second dose given 3 months after the first. The need for a booster dose has not been established.^[2]

What do the clinical trials show?

One trial is registered in the EU Clinical Trials Information System for this vaccine. It is an open, non-randomised phase 3 trial being conducted in Sweden.^[1] The trial plans to enrol 45 healthy travellers who will receive two doses of Qdenga.^[1] The study is examining whether vaccination causes significantly elevated levels of cross-reactive IgG antibodies against tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), Zika virus (ZIKV) and Japanese encephalitis virus (JE) at day 90 after two doses, compared to before vaccination.^[1] The trial status is Authorised, meaning it has received approval to proceed.^[1]

What side effects are known?

The package leaflet for Qdenga states that the medicine is subject to additional monitoring, which allows quick identification of new safety information.^[3] The leaflet advises that side effects can occur and that any side effects, including those not listed in the leaflet, should be reported to a doctor, pharmacist or nurse.^[3] Specific side effects are described in section 4 of the patient leaflet, but the detailed list is not included in the available source material.^[3]