Moderna has temporarily halted its Phase 1 trial of an mRNA vaccine designed to treat the Epstein-Barr virus (EBV) following a suspected case of myocarditis in an adolescent participant.
Independent journalist Alex Berenson reported that Moderna paused the “Eclipse” trial after receiving an urgent communication indicating the need for an immediate suspension of dosing for all adolescents. The company did not publicly disclose the trial suspension in its filings, leading to questions about potential financial motivations.
The incident has sparked concerns about the mRNA platform’s safety, particularly regarding heart-related issues such as myocarditis. Moderna’s mRNA COVID-19 vaccines, along with those from Pfizer, have previously been linked to myocarditis, especially in young and healthy males.
Berenson emphasized that the mRNA design used in the EBV vaccine is similar to that of Moderna’s COVID-19 shot, involving modified mRNA enclosed in lipid nanoparticles. The uncertainty persists about whether it is the spike protein or the lipid nanoparticles causing myocarditis in COVID-19 vaccine recipients.
Myocarditis, characterized by inflammation of the heart muscle, can lead to severe complications, including cardiac arrest and death. Studies, including one published in Nature Immunology, have explored the role of lipid nanoparticles in triggering inflammation.
The lack of transparency surrounding the link between mRNA vaccines and myocarditis dates back to 2021, with Berenson citing instances where the U.S. Department of Defense and the Israeli health ministry identified higher-than-expected myocarditis cases following mRNA vaccination. The CDC’s delayed response to safety signals raised concerns about the thoroughness of public disclosures.
Berenson suggested that Moderna’s approach echoes past controversies, including Israel’s warning of myocarditis cases after Pfizer’s COVID-19 vaccine in February 2021. The CDC’s slow acknowledgment of this information and meetings with the Department of Defense raised questions about transparency.
Moderna initiated the trial for the mRNA-1189 EBV vaccine in January 2022, initially enrolling participants aged 18 to 30 and later expanding to include adolescents as young as 12 in Phase 1 part B. The vaccine aims to prevent infectious mononucleosis and EBV infection, with participants having no history of myocarditis or pericarditis.
EBV, a common viral infection, has been linked to various malignancies, and Moderna is developing another vaccine, mRNA-1195, to prevent long-term EBV sequelae. The company’s investor overview associates EBV with multiple sclerosis and EBV-related malignancies.
Moderna CEO Stéphane Bancel sees the EBV study as a significant milestone in advancing mRNA vaccines against latent viruses that persist in the body, potentially leading to chronic medical conditions. Despite concerns and the stock price decline, Moderna remains a valuable biotech company with a $30 billion market value.