World-First mRNA Vaccine Could Topple Number One Killer Of Baby Asian Elephants

A deadly disease for baby Asian elephants is the target for an mRNA vaccine that has been administered to an elephant for the first time. Elephant endotheliotropic herpesvirus (EEHV) is the number one killer for Asian elephant calves living under managed care in North America and Europe, and is a significant threat for free-ranging populations. It has also been connected to a number of African elephant deaths in the United States.

EEHV is so deadly because it can cause hemorrhagic disease characterized by damaged blood vessels, bleeding, and organ failure. To prevent this, the EEHV mRNA vaccine exposes elephants to the viral proteins that enable the virus to enter the host’s cells, effectively preparing them so that they can launch an immune attack should the same viral proteins come knocking again. This means their bodies can fight off EEHV before it’s had a chance to take hold.

The world-first vaccine was developed by Dr Paul Ling of the Baylor College of Medicine in partnership with Houston Zoo, with a helping hand from a few unexpected places. There’s Colossal Biosciences, the de-extinction giants trying to bring back mammoths and save a few endangered species along the way, and the COVID-19 vaccine.

Colossal helped to provide research support and acceleration funding for the vaccine. Meanwhile, the rapid deployment of the COVID-19 vaccine – and all the pipelines that enabled its fast development – energized the efforts to develop the mRNA-based vaccine for EEHV.

Extensive preclinical trials demonstrated that the resulting vaccine could induce an immune response without adverse side effects. It has now been given to a 40-year-old Asian elephant named Tess, who will be monitored to see if the vaccine can be rolled out to other elephants.

Tess’s shot targets the EEHV1A strain of the virus, which is behind the majority of deadly cases among Asian elephants. However, the team behind its creation is hopeful that it can be easily modified to target other strains in circulation, including the one affecting African elephants.

“The goal of the vaccine is first, to be safe to the elephants upon administration,” Colossal Biosciences told IFLScience. “Secondly, to stimulate the immune system of the elephant to activate immune cells and release antibodies that neutralize the virus upon infection or activation.”

“Thirdly, the memory cells of the immune system have to ‘remember’ to neutralize the same virus in the future in a faster, more efficient manner. And finally, to identify all vulnerable individuals in zoos and administer it at the right window of time to provide protection, which should be usually around the time their young bodies are weaned off the protective antibodies provided by the mother early in life.”

It’s a big step to safeguarding young captive elephants from this deadly disease, as well as those out in the wild, but it’s also hoped it could have applications in human medicine.

“The technology to develop the first EEHV mRNA vaccine is based on the already successfully deployed technology of the Covid vaccine,” added Colossal. “But success in immunizing against EEHV will further enable more focused efforts for vaccine development in other human herpesviruses (HHVs) that are also double stranded DNA viruses, and more broadly to other viruses in the Herpesviridae family which does include HSVs.”