In July 2022, the WHO Director-General responded to a multi-country outbreak of M.P.O.X., which spread rapidly through sexual contact in previously undetected countries, and raised concerns of international concern. declared a public health emergency (PHEIC). This PHEIC was lifted in May 2023 following a sustained decline in the number of infected people worldwide. Due to the emergence of a new clade Ib and the resurgence of mpox cases in the African region, WHO declared PHEIC again on August 14, 2024. The current outbreak in affected African countries also includes other high-risk groups such as pregnant women and women. Children under the age of 18, including infants.
Previously, GACVS presented three available mpox vaccines (MVA-BN, LC16m8 , and ACAM2000 vaccine). Reviews and recommendations are published in the Weekly Epidemiological Record (WER)(1). The “Smallpox and mpox (orthopoxviruses): WHO position paper” published in August 2024 provides guidance on the use of currently available vaccines (2).
On September 20, 2024, WHO GACVS announced that the European Medicines Agency (EMA), the US Centers for Disease Control and Prevention (CDC), and the Pharmaceuticals and Medical Devices Agency (PMDA) would Updated based on sex data. Two third-generation vaccines (modified/non-replicating vaccinia virus (MVA)-BN (Jynneos/Imvanex/Imvamune, Bavarian Nordic) and minimally replicating LC16m8 vaccine (KM-Biologics)). GACVS has been updated with post-approval safety data for the MBA-BN vaccine and safety findings from clinical studies of the LC16m8 vaccine.
Given the limited data available, the risk management plan by Bavarian Nordic for the use of the MVA-BN mpox vaccine in African countries, as MVA-BN is a non-replicating vaccine and can also be used in pregnant women. GACVS has been updated based on: GACVS welcomed additional clinical studies planned by Bavarian Nordic to address questions regarding the use of the vaccine in infants aged 6 months to 2 years, children aged 2 to 12 years, and pregnant women.
Current post-approval data show that these vaccines have a favorable safety profile in adults, which is broadly consistent with pre-licensure clinical trial data, but to detect potential safety signals, Close monitoring is recommended.
Different types of mpox vaccines use different methods of administration (e.g. subcutaneous, intradermal, bifurcated needle). Therefore, especially for the LC16m8 vaccine, it is strongly recommended that healthcare workers be specifically trained in intradermal injection techniques, including the use of bifurcated needles, to minimize the possibility of adverse events related to vaccination errors. Recommended. Local reactogenicity to this vaccine administration also needs to be monitored.
GACVS was briefed on how countries are preparing for safety monitoring after vaccine introduction. The Committee was then updated on the draft WHO Protocol: Cohort Event Monitoring (CEM) for active safety surveillance of Mpox vaccines. GACVS uses a standardized CEM protocol to assess the initial stage after vaccine introduction, especially given the limited data on high-risk groups such as infants, children under 12 years, immunocompromised individuals, and pregnant women. emphasized the importance of capturing potential safety signals. .
The Committee emphasizes the importance of monitoring the safety of both the mpox vaccines MVA-BN and LC16m8 in all target populations in which they are used, including off-label use. It is important to note that MVA-BN can also be used in immunocompromised individuals and pregnant women, but LC16m8 is not recommended for use in these populations. Special attention should also be given to infants, children, and breastfeeding women.
The Commission encourages the use of tools such as Vigiflow, VigiMobile, and the Med Safety App for voluntary reporting of adverse events. GACVS will ensure that public health authorities, researchers, regulators, marketing authorization holders and other key stakeholders carry out comprehensive and coordinated vaccine safety monitoring and research, and that these groups conduct clinical trials during clinical trials. We recommend identifying rare or unknown undetected adverse events. The WHO Protocol: Cohort Event Monitoring for Active Safety Surveillance of Mpox Vaccines will assist countries in conducting cohort event monitoring of Mpox vaccines.
It also noted that there are limits to the application of these vaccine use restrictions to HIV-infected individuals with CD4 cell counts below 200 cells/μL due to difficult access to diagnostics and laboratory testing in these settings. . Therefore, the committee recommended closely monitoring the safety of people living with HIV and communicating the risks and benefits, while ensuring follow-up. Safety also needs to be monitored more closely in vaccinated populations, with high rates of HIV infection, undiagnosed populations, and those not receiving clinical management.
