ModernaModerna (NSDQ:MRNA) has dosed the first volunteer in the Phase 1 Eclipse study of mRNA-1189, an Epstein-Barr virus vaccine candidate.

The study will take place at roughly 15 sites in the U.S. and involve approximately 272 healthy adults between the ages of 18 and 30.

The study will be randomized, observer-blind, placebo-controlled and involve a range of doses.

Epstein-Barr virus (EBV) is one of the most common viruses, representing one of the viruses that cause infectious mononucleosis (mono). EBV is also linked to a heightened risk of multiple sclerosis and some cancers and autoimmune diseases.

EBV seroprevalence tends to rise with age, affecting 90–95% of adults.

“Adolescents who develop infectious mononucleosis are frequently absent from school for weeks and even months at a time, impacting the quality of their education and their families,” said Stéphane Bancel, Moderna CEO, in a press release.

Pfizer (NYSE:PFE) and BioNTech (NSDQ:BNTX) are also working on expanding their footprint in mRNA vaccines and have announced a collaboration focused on an experimental shingles vaccine.