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Is this the end for Zika?

Is this the end for Zika?

Researchers at KU Leuven have developed a new vaccine against Zika, the mosquito-borne virus that sparked a global health emergency in 2016.

6 minutes
02 October 2019

Researchers at KU Leuven have developed a new vaccine against Zika, the mosquito-borne virus that sparked a global health emergency back in 2016. Although no longer a worldwide health threat, the infection has been linked to thousands of babies being born with underdeveloped brains. Today, KU Leuven scientists from the Rega Institute are hopeful that their vaccine will prevent the virus from causing additional cases of microcephaly and other severe neurological defects in new-borns.

Researchers at KU Leuven Hopeful about New Vaccine

KU Leuven researchers have made yet another important step in the fight against the Zika virus, which caused global concern a few years ago. The virus was first identified in monkeys in Uganda’s Zika forest in 1947. In 1954, the first infected human was discovered in Nigeria. Since then, there have been further outbreaks in Africa, South East Asia and the Pacific Islands. In May 2015, a rising number of Zika cases were reported in Brazil and the virus spread rapidly to the rest of Latin America. The World Health Organization soon declared the Zika virus a global public health emergency. Following the WHO’s declaration, some areas declared a state of emergency, and doctors even advised women in affected countries to postpone getting pregnant.

The lack of media attention for the virus in recent months may lead you to believe the virus has disappeared, but make no mistake: Zika is still ‘alive and kicking’. True, there has been a steep decline in Zika cases since 2016, yet the threat posed by the virus has not diminished. Although it might be under control, Zika did not completely vanish from the face of the Earth. In fact, researchers warn that Zika might be here to stay. After all, there is still potential for the seemingly dormant virus to spread further (internationally), given the wide geographical distribution of the mosquitoes that carry it.

Zikavirus vrouw handschoen

Deadly mosquitos

That’s right, although global health experts continue to investigate whether the virus can be transmitted sexually, it was long established Zika is primarily spread when people are bitten by an infected Aedes or Asian tiger mosquito. This small black-and-white striped insect is also known for carrying dengue and yellow fever. Alarmingly, the tiger mosquito has been making its way to our regions for some time now, and has recently even been spotted in Belgium. No need for panic, though: the mosquitoes themselves do not present any danger of Zika outbreaks in our country. To transmit the virus, the mosquito must first bite an infected person.

If a healthy person is bitten by an infected mosquito, they might not show any symptoms at all, or it could lead to a very mild infection. Elderly people or people with weakened immune systems may display more severe symptoms. For pregnant women, however, consequences may be a lot more serious. They include pregnancy loss, and there is evidence it causes birth defects, in particular babies born with an abnormally small head and brain – a condition known as ‘microcephaly’. The full spectrum of outcomes for infants infected with Zika is still being studied, but it has also been linked to impaired growth in babies, as well as developmental delays. Furthermore, researchers found that the virus could cause glaucoma and hearing loss. In 2016, nearly 30 countries reported birth defects linked to Zika, with over 2,000 cases of nervous-system malformations reported in Brazil alone. Pictures of deformed babies raised enormous concern around the world, right at the time Brazil was about to host the 2016 Olympics. This international outbreak spurred on scientists around the world in the race towards finding a vaccine to protect us against the virus.

Zikavirus mosquito

Yellow fever

Scientists at the KU Leuven Rega Institute are optimistic they can now finally bring that intense search for therapeutics and antidotes to an end. Together with their team, Professor Neyts and Dr. Kai Dallmeier have managed to develop the much-coveted vaccine by making use of the existing yellow fever vaccine. Yellow fever and Zika are actually closely related, and both diseases are transmitted to humans through the bite of the same mosquito.

By replacing part of the genetic information of the yellow fever vaccine with the corresponding piece of code of the Zika virus, the scientists were able to create a very safe and effective vaccine. During the engineering process, they relied on in-house state-of-the-art technology, allowing the vaccine to be produced in their lab’s fermenters instead of fertilised chicken eggs. In collaboration with their colleagues at the University of Liège, the KU Leuven team performed initial tests on pregnant mice, with promising results: After being injected with the vaccine, Zika infected mothers gave birth to perfectly healthy pups.

As the Zika virus has mostly raged in Latin America and the Caribbean, i.e. locations where the climate is typically (sub)tropical and humid, it is crucial to note that the newly developed vaccine remains stable, even at high temperatures. This is absolutely key for a vaccine that is to be used in the most remote corners of the world. In addition, the vaccine guarantees lifelong protection, the team at KU Leuven adds.

Zikavirus diepvries

Beyond the Horizon

The KU Leuven researchers have their heart set on making a difference in those areas where it matters most. In order to foster these all-important international collaborations, they reached out to Horizon 2020, the biggest EU Research and Innovation programme. Following the publication of a specific call to address the Zika research gaps, two KU Leuven consortia were selected for EU Horizon 2020 funding, i.e. ZikAlliance and ZikaPLAN. Aiming to improve (scientific) response to Zika outbreaks, these consortia set out to fill the knowledge gaps on Zika infection and its consequences for pregnant women, new-borns and adults. They will work together to establish a Latin American and Caribbean network, and will focus on improving current diagnostic tests, treatment and prevention.

The first consortium is the multidisciplinary ZikAlliance, which was awarded 12 million euros worth of European funding in order to support their three-year research project. ZikAlliance unites no fewer than 52 partners from 18 different countries, with KU Leuven being one of them. Professor Neyts’ Laboratory of Virology will be joining forces with the Leuven Centre for Drug Design & Discovery (CD3), led by Dr. Patrick Chaltin. Their goal is to develop an antiviral drug, which can prevent or treat Zika infections. Moreover, the team led by Professor Catherine Verfaillie will focus on the effects Zika has on our brain cells. In addition, Professors Anne-Mieke Vandamme, Philippe Lemey and Jelle Matthijssens will zoom in on genetic diversity, molecular evolution and the geographic spread of the virus.

The second consortium that will be supported by the EU is ZikaPLAN, short for ‘Zika Preparedness Latin American Network’. A total of 25 partners, including KU Leuven and the Antwerp Institute of Tropical Medicine, are awarded 11.5 million euros in support of their research efforts. Within this consortium, scientists will be looking for answers to the most pressing questions concerning the current epidemic. Relying on previous findings, Professor Neyts and his team plan to study the sexual transmission of the Zika virus, as well as its transmission during pregnancy.

Clearly, officials, medical professionals, policy makers and the general population are right to continue to show concern about Zika. Its rapid (re-)emergence, new modes of transmission, and the detrimental consequences associated with the virus are truly alarming. Nevertheless, as the scientists at the KU Leuven Rega Institute have demonstrated, ongoing research efforts, a strong determination to find a vaccine, and widespread international collaboration imply that success is within reach, and a lot of future suffering will be prevented.