Vaccines against mpox: MVA-BN and LC16m8

Global outbreaks involving mpox clade IIb began in mid-2022. Today, clade IIb and clade I outbreaks continue. Reliable mpox vaccines can prevent serious mpox disease and death. Globally, two vaccines hold mpox indications, regardless of mpox viral clade: MVA-BN (Bavarian Nordic) and LC16m8 (KM Biologics). This review summarizes the human and pivotal animal data establishing safety and efficacy for MVA-BN and LC16m8, including real-world evidence gathered during mpox outbreaks from 2022 through 2024. Some regulatory decisions for MVA-BN and LC16m8 followed pathways based on surrogate outcomes, including lethal-challenge studies in nonhuman primates, among other atypical aspects. Nonetheless, MVA-BN and LC16m8 hold unencumbered registration in multiple countries. Effectiveness of MVA-BN as primary preventive vaccination (PPV) in humans against clade IIb mpox is clear from real-world studies; effectiveness of LC16m8 against clade IIb is likely from surrogate endpoints. Effectiveness of MVA-BN and LC16m8 as PPV against more-lethal clade I is likely, based on animal-challenge studies with multiple orthopoxvirus species and other studies. Both vaccines have solid safety records. MVA-BN’s replication incompetence favors adoption, whereas LC16m8 has more pediatric data. Additional real-world evidence, in additional geographic settings and special populations (e.g. pregnancy, immune suppression, atopic dermatitis), is needed. Mpox outbreaks spread
globally in 2022, hospitalizing many people. Many recent mpox cases in Africa
occur in children. Two vaccines, known as MVA-BN and LC16m8, can help prevent mpox. MVA-BN protects
animals from lethal doses of mpox and similar viruses. During outbreaks, MVA-BN
lowered the chance of mpox disease by 62% to 85%. In people already exposed to mpox,
MVA-BN reduced disease risk by 20%. MVA-BN may help reduce how serious mpox
cases are, even if this vaccine does not block infection fully. MVA-BN cannot
grow inside the body, making it very safe, even in children. Side effects
include pain, redness, swelling, and itching. Some people feel muscle pain, headache,
fatigue, nausea, or chills after vaccination. Several million people have
received MVA-BN so far, including thousands of people living with HIV. LC16m8 protects
animals from lethal doses of mpox and similar viruses. There are not much data about
LC16m8 used during mpox outbreaks. LC16m8 contains a weakened virus. Side
effects include fever, fatigue, redness, swollen lymph nodes, and itching.
Vaccine virus can spread to other parts of the body. Over 90,000 people have
received LC16m8 so far. No significant safety signals were found after these
doses, including 50,000 children. People who are immunosuppressed, have certain
skin diseases, or are pregnant should not be given LC16m8. Health officials recommend mpox vaccine for people at risk, including
children.