LC16m8 for Pre-exposure Prophylaxis Against Mpox in a High-Risk Population: An Open-Label Randomized Trial.

Area of Science:

• Infectious Diseases
• Vaccinology
• Public Health

Background:

• Mpox (formerly monkeypox) poses a significant public health threat, necessitating effective prevention strategies.
• Pre-exposure prophylaxis (PrEP) with vaccines like LC16m8 is being investigated for high-risk populations.
• Understanding vaccine safety and immunogenicity is crucial for widespread adoption.

Purpose of the Study:

• To assess the efficacy of LC16m8 vaccine for mpox prevention.
• To evaluate the safety and immunogenicity of LC16m8 in a high-risk population, including individuals with HIV.
• To compare early versus late vaccination schedules.

Main Methods:

• A multicenter, randomized, open-label trial involving adults at high risk for mpox.
• Participants were randomized to receive LC16m8 vaccine early or late in the study.
• Primary endpoint: vaccine efficacy (VE) against mpox; Secondary endpoints: severe mpox, symptoms, adverse events (AEs), and immunogenicity, particularly in participants with HIV.

Main Results:

• No mpox cases were reported, thus primary efficacy could not be calculated.
• High seroconversion rates observed: LC16m8 (96.2% with HIV, 92.0% without HIV) and MPXV (69.2% with HIV, 52.0% without HIV) in participants with HIV.
• The vaccine was generally well-tolerated, with high take rates and a low incidence of serious adverse events (SAEs).

Conclusions:

• LC16m8 demonstrated immunogenicity and an acceptable safety profile in individuals with well-controlled HIV.
• The study suggests LC16m8 may be suitable for targeted mpox vaccination in at-risk groups.
• Further studies are needed to confirm vaccine efficacy in preventing mpox infection.