The US’ National Institutes of Health (NIH) trial evaluating the Bavarian Nordic’s Jynneos mpox vaccine advances to the next stage to study immune responses and safety in adolescents.

George Washington University is one of the 18 clinical sites across the US testing the vaccine. The university’s participation is funded by Frederick National Laboratory for Cancer Research, which provides scientific support to NIH.

The Jynneos vaccine was approved by the FDA in 2019 for use in adults to prevent smallpox and mpox. In 2022, it received FDA’s emergency use authorization (EUA) to use in individuals under the age of 18 who are at a high risk of mpox infection.

The latest stage of the trial (NCT05512949) will investigate immune response and safety in people aged 12 to 17, and whether results are comparable to those aged 18 to 50 years. The trial is sponsored by the National Institute of Allergy and Infectious Diseases (NIAID).

George Washington University plan to recruit around 315 adolescents who will receive the standard subcutaneous dose of Jynneos. The university also plans to test 135 adults aged 18 to 50 as a comparison group. The trial will last 13 months, and investigators will measure antibody response along with safety.

George Washington University medicine professor David Diemert said: “We are excited to have launched the next stage of this clinical trial, which can help determine if this vaccine can be used to protect adolescents should there be another large outbreak in the United States or some other part of the world.

“Having a safe and effective vaccine at the ready would help prepare the United States and other countries for the next outbreak of this disease.”