Research News

As mosquito-borne diseases continue to emerge and spread in new regions, Cleveland Clinic’s vaccine development program is demonstrating how quickly it can respond to viral threats. When a new outbreak of Oropouche virus (also called "sloth fever") was reported in late 2023, researchers in the laboratory of Jae Jung, PhD, mobilized quickly. In just over a year, they developed two successful mRNA vaccine candidates. They published their work in mBio, showcasing their ability to quickly move from detection to candidate development. 

As the chair of Cleveland Clinic’s Department of Microbial Sciences in Health and the director of Cleveland Clinic's Sheikha Fatima bint Mubarak Global Center for Pathogen & Human Health Research, Dr. Jung leads Cleveland Clinic’s broader strategy to prepare for and swiftly respond to emerging viral threats. 

“No licensed vaccines or therapeutics are currently available for Oropouche virus, despite its expanding range and rising incidence,” Dr. Jung says. “As insect-borne diseases reach new places due to changes in the environment, we need to turn around strong solutions quickly to prevent public health problems.” 

What are mosquito-borne diseases? 

Mosquito-borne diseases are spread when a mosquito sucks blood from an infected person or animal. The mosquito's infected saliva will then enter the bloodstreams of anyone else it bites. 

Oropouche virus is spread by mosquitoes, but mainly through a species of biting midge commonly called “no-see-ums.” 

According to Yumiko Yamada, PhD, a postdoctoral researcher in the Jung Lab, human contact with infected insects is increasing because: 

• Environmental changes help insects that spread viruses survive in new areas.
• More people are moving into previously remote, forested regions.
• Growing cities and expanding urban areas mean these insects live in more populated areas.  

“Tens of thousands of infections have emerged since December 2023,” explains Dr. Yamada, who is also co-first author of the mBio publication. “For over 70 years after its discovery, Oropouche virus only caused sporadic outbreaks limited to parts of the Amazon basin. In these past two years, we’ve seen a dramatic and unexpected surge in cases across multiple countries where the virus had never been reported.” 

Cleveland Clinic’s vaccine development program drove rapid progress 

Dr. Yamada teamed up with the study’s other co-first author, PhD student Inho Cha, to develop two different Oropouche virus vaccines in August 2024. 

“Our lab is a well-established member of Cleveland Clinic’s global vaccine development program,” Cha explains. “We are well equipped to produce and test vaccine candidates in a remarkably short amount of time.” 

The Jung Lab brings deep experience in developing and improving vaccines for emerging threats, including: 

• Dabie bandavirus (also called severe fever with thrombocytopenia virus)
• SARS-CoV-2
• A cancer-causing virus called Kaposi’s sarcoma-associated herpesvirus 

The team developed lipid-based nanoparticles that bundle and deliver immune-boosting mRNA sequences. The lab’s earlier work with nanoparticle vaccines showed that mRNA packed in a bubble of fat worked better and caused fewer side effects than free‑floating mRNA. 

Cha and Dr. Yamada developed two different vaccine candidates based on viral strains from before and after the current outbreak. Comparing them was key to finding the candidate with the most effective and broadest protection. The more promising vaccine candidate was made using the strain behind the current outbreak.  

“Ultimately, the decision to advance to clinical trials depends on many questions about efficacy and safety that we are working to answer. I’m still very proud of how far Inho and I have brought this project in just a year,” Dr. Yamada says. “As a postdoc, co-leading a project with direct impact on global health has been both exciting and deeply fulfilling.”