In November 2022 CEPI and the University of California, Davis announced a partnership agreement to “advance and expand the application of ‘SpillOver’”. This is a viral ranking app that compares the risks presented by animal and human viruses. With funding from CEPI the app will go to the “next level”.  


The database reportedly ranks hundreds of “virus, host, and environmental risk factors” to identify viruses with the highest risk of zoonotic spillover. UC Davis researchers developed the open database with data from 509,721 samples from 74,635 animals across 28 countries and public records. Then, the data were used to “rank the spillover potential” of 887 wildlife viruses.  

With up to US$1.76 million from CEPI, the app’s database will expand to include “new risk factors”. These include viruses that infect domesticated animals or those “harboured by reptiles and amphibians”. The UC Davis One Health Institute will also “pioneer a new system” with the support of artificial intelligence, to analyse “multiple sources” in search of data. 

Viral top trumps 

Recent findings published in PNAS and based on over 30 risk factors indicate that Lassa virus is the highest risk pathogen after SARS-CoV-2. There are currently no licensed vaccines against Lassa fever, but a collaboration between IAVI and CEPI aims to address this.  

As well as developing vaccines against known diseases, CEPI states that it is possible to develop “prototype vaccines” against different virus families. These can then be adapted quickly as a new virus is identified. CEPI hopes to build a ‘library’ of vaccine candidates in time for Disease X. This is part of the $3.5 billion 100 Days Mission, a “plan to compress vaccine development timelines to 100 days”.  

Viral families 

Dr Melanie Saville, Executive Director of Vaccine Research and Development at CEPI, suggests that “most viruses that cause disease in people are descended from one of around 25 families”.  

“There are viruses out there that we don’t yet know about, also known as Disease X, but which are likely to come from one of these 25 or so viral families”.  

Through the partnership with UC Davis CEPI hopes to “home in” on these viral families. Thanks to globalisation, we are more “vulnerable to the rapid spread of new zoonoses”. Thus, the identification of “another pandemic disease” is predicted to come any time soon. Additionally, the risk is “further heightened by our warming climate”, which expands the range of disease-carrying creatures and increases their interaction with human populations. Dr Jonna Mazet of UC Davis is “thrilled” to be collaborating with CEPI to “create a healthier future for us all”.  

“Together we will use cutting-edge methods to dramatically increase the amount virus data available for risk ranking. This is a critical step forward in streamlining vaccine pipelines with the power to revolutionise epidemic and pandemic preparedness.”  

For more on preparation for Disease X at the World Vaccine Congress in Washington 2023, get your tickets now.