Novel vaccine against dengue tested successfully in Switzerland

© Keystone / Ennio Leanza

The results of a clinical study on a new type of vaccine that induces cellular immunity to combat dengue fever are positive and encouraging.

Unisanté in Lausanne has conducted a clinical study on a new type of vaccine that induces cellular immunity to combat dengue fever. The results, published in The Lancet eBioMedicine, are positive and encouraging.

Global warming and urbanisation are facilitating the spread of the tiger mosquito, responsible for dengue fever. The WHO estimates that almost half the world’s population lives in high-risk areas, and cases of dengue fever have increased eightfold in 20 years. Having an effective vaccine is therefore a priority, Unisanté said in a press release on Monday.

Two dengue vaccines are currently available in Europe, but they are proving unsatisfactory in terms of safety and efficacy. Their technology is based on the production of antibodies which, in certain cases, can increase the severity of the disease.

This is why Unisanté has assessed the safety and immune response of a potential vaccine designed using an innovative technology to induce cellular immunity, without stimulating the production of antibodies.

A new approach

The vaccine tested, PepGNP-Dengue, was developed by Emergex Vaccines, a UK-based biotechnology company. It consists of a nanodose of synthetic fragments of the virus fused to gold nanoparticles. Another special feature is that it is administered under the skin using a micro-needle.

The vaccine relies on T lymphocytes, which are responsible for cellular immunity, to eliminate cells infected by the virus and prevent it from replicating. To assess the safety of this vaccine, which is being administered to humans for the first time, the company chose Unisanté because of the institution’s accumulated experience in evaluating candidate vaccines against Ebola and malaria in particular.

The aim of this phase 1 study was to determine whether the vaccine did not induce severe undesirable side-effects in healthy volunteers. A total of 26 participants aged between 18 and 45 were vaccinated in Lausanne in 2021, and followed for six months until March 2022.

Also against Covid

In the study conducted by Blaise Genton and Alix Miauton’s team, no serious adverse events were reported. Local side-effects (e.g. pain at the injection site) were the most frequently reported.

The immunological results indicate that PepGNP-Dengue can stimulate a specific cellular response against the dengue virus, without producing antibodies. This work encourages further investigation of this vaccine candidate and is considered promising for other diseases where cellular immunity is important.

A potential vaccine for Covid-19, based on the same technology, was also tested by Unisanté on 26 participants. The results are currently being published.

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