The Chester Zoo in England isn’t new to elephant conservation.
In 1977, they became the first zoo in the United Kingdom to successfully breed Asian elephants in captivity, a practice that they continue today with greater urgency.
According to the World Wide Fund for Nature (formerly known as the World Wildlife Fund), Asian elephant populations have declined by at least 50% in the past three generations.
In addition to threats from habitat loss, deforestation, and poaching, the Asian elephant — which is listed as endangered by the International Union for Conservation of Nature — has also been facing a mounting threat in the form of the Elephant endotheliotropic herpesvirus.
EEHV is a rapid, dangerous disease that causes acute blood loss issues and can lead to an elephant’s death within 24 hours of them first exhibiting symptoms. It is especially fatal to elephants under the age of eight.
In 2009, the Chester Zoo lost an elephant calf to EEHV, a tragedy that would later prompt the “Never Forget Campaign.” The zoo raised £250,000 through the fundraiser, which helped kickstart vital research into developing a vaccine.
“In 2019, our calf Indali Hi-Way became one of only a handful of recorded survivors after intensive treatment,” the zoo said in a press release. “By 2021, the first doses of this vaccine were trialled here at the zoo.”
“And now,” they shared, “in 2025, with trial results published, the vaccine can be rolled out worldwide.”
“This vaccine was first delivered to an elephant here at Chester Zoo in 2021,” said lead conservation scientist and study co-author Katie Edwards. “But this publication marks a watershed moment — it means we can now say the vaccine is ready for wider use.”
“EEHV has taken the lives of so many elephants, but this offers hope and a massive step towards ending those losses.”
Falko Steinbach, a professor of veterinary immunology at the University of Surrey, called it a “landmark moment” for elephant conservation.
“For the first time, we have shown in elephants that a vaccine can trigger the type of immune response needed to protect them against EEHV,” said Steinbach, who served as a senior author of the study.
Javier Lopez, Chester Zoo’s head of veterinary services, emphasized the importance of making the vaccine as accessible as possible as it rolls out worldwide.
“As a conservation charity, our goal is for the vaccine to be open source and freely available to help save as many elephants as possible,” Lopez said. “Until now, EEHV has been a silent killer — with this vaccine, we finally have a weapon to fight back.”
You may also like: Park rangers in Senegal celebrate as beloved 'Ghost elephant' makes rare appearance
Header image via Ad Meskens / Wikimedia Commons (CC BY-SA 4.0)
