Preventive action against deadly tick-borne disease
Crimean-Congo Haemorrhagic Fever (CCHF) is a deadly virus spread by a species of tick, with no licensed vaccine. Symptoms include fever, headache and severe bleeding, with fatality rates of up to 40 %. “This disease is often found in less developed countries and is not widespread,” notes CCHFVaccine(opens in new window) project coordinator Ali Mirazimi from the Public Health Agency(opens in new window) and Swedish Veterinary Agency in Sweden. “As a result, it is somewhat of a neglected disease with no major interest from pharmaceutical companies.”
Developing a vaccine against CCHF
CCHF has nonetheless increasingly found itself on Europe’s radar. A key reason for this is that the ticks responsible for spreading the disease are popping up all over the continent, from eastern Europe to Portugal and even Sweden. The fear is that unless Europe is adequately prepared, a CCHF outbreak could have devastating consequences. “These ticks are increasingly moving north because of climate change,” explains Mirazimi. “They are often brought by migratory birds, and if the conditions are good, they will survive. One tick can produce thousands of eggs.” The best solution to head off any disaster is prevention. This means developing a vaccine. Mirazimi is one of Europe’s foremost CCHF experts, and the EU has supported his work in this field since the CCH FEVER project in 2010. CCHFVaccine is very much a continuation of this work. “It became clear that a vaccine was the way to go,” says Mirazimi. “Our experience with COVID-19 demonstrated that we can bring a vaccine forward in a matter of months if the knowledge, resources are there, and there is interest from companies and regulatory authorities.”
Accessing samples in endemic regions
The CCHFVaccine project involved three distinct steps. The first was to advance viable animal models, which are necessary before human trials can begin. The second was to trial all vaccine platforms available to determine the most likely to succeed. Finally, the project sought to create a pipeline for human samples, which are needed for developing assays to see if a vaccine is working. “These samples are found only in endemic areas, which are often remote and hard to get to,” remarks Mirazimi. “Even shipping these samples is complex. We therefore set out to establish infrastructures to deal with this, and to build capacity in countries like Türkiye, Kosovo and Tajikistan.” To make these three aims possible, the project successfully brought together some of the best scientists in the field. The team was also able to access high-containment labs, which are needed to deal with dangerous pathogens.
Bringing forward an mRNA vaccine
The project achieved successes in all three aims. Sheep models were developed for testing vaccines (sheep are often infected by ticks) and an animal roadmap was outlined to bring clinical testing to the human stage. The team was also able to identify genetic vaccines based on DNA and mRNA as the best candidates to pursue. “Due to our experience from the COVID pandemic, we have excellent knowledge on the safety of mRNA vaccines,” adds Mirazimi. Capacity building was also carried out. A hospital unit in north-east Türkiye was built to collect samples, carry out diagnostics and securely send on samples. All this work will now be continued through a new EU-funded project, CCHFVACIM. The aim of this is to bring forward an mRNA vaccine, ready for phase II clinical trials.
