Emergent BioSolutions announced that the U.S. Food and Drug Administration (FDA) has approved the supplemental Biologics License Application (sBLA) for the expansion of the indication for ACAM2000®, (Smallpox and Mpox (Vaccinia) Vaccine, Live) to include prevention of mpox disease in individuals determined to be at high risk for mpox infection. The approval is based on previously available human safety data and data from a well-controlled animal study in which ACAM2000® vaccine was shown to be effective in protecting against mpox virus exposure.

ACAM2000® is a single-dose vaccine administered percutaneously via a bifurcated needle that is dipped into the vaccine solution and the skin is pricked several times in the upper arm with a droplet of the vaccine.

The vaccine was first approved by the FDA in 2007 for active immunization for the prevention of smallpox disease in individuals determined to be at high risk for smallpox infection. Mpox, previously called monkeypox, is an infectious disease endemic to central and west Africa caused by the double-stranded DNA mpox virus. The virus is a member of the Orthopoxvirus genus in the Poxviridae family, related to the virus which caused smallpox, which was eradicated in 1980.

“The FDA approval of ACAM2000® for immunization against mpox in high-risk individuals further strengthens and broadens our industry-leading smallpox portfolio, which includes VIGIV® and TEMBEXA®, said Joe Papa, president and CEO of Emergent. “This expanded indication for ACAM2000® comes at a critical time as the global health community comes together to ensure an effective and cohesive response to the recent upsurge in mpox cases. We believe Emergent is poised to support the global response needed by actively engaging with world health leaders, as well as deploying product currently available in inventory based on the needs, as well as the ability to increase supply.” 

This approval follows Emergent’s announcement that it filed an Expression of Interest (EOI) with the World Health Organization (WHO) for the WHO’s assessment of ACAM2000® vaccine to be added as an Emergency Use Listing in connection with the mpox outbreak. Emergent also is in discussions with other global public health leaders to help address the current mpox outbreak in response to the WHO’s Director-General’s August 14 statement declaring that the upsurge of mpox is a public health emergency of international concern under the International Health Regulations. As part of its support to the response, Emergent announced that it will donate 50,000 doses of ACAM2000® for potential deployment across impacted countries in Central Africa.

“Mpox has progressed to become an uncontrolled epidemic in Africa — prompting the WHO to declare a second public health emergency of international concern — creating an enormous need to use all effective tools to extinguish it as a threat,” said Dr. Amesh A. Adalja, FIDSA FACP FACEP & health security and emerging infectious diseases expert, Johns Hopkins Center for Health Security. “ACAM2000®, a direct descendant of the Jenner vaccine (humanity’s first) which was used to eradicate smallpox, and now with the broadened indication, will be an invaluable tool in this endeavor.”  

In 2022, the world experienced a global outbreak of clade II mpox, which led to more than 95,000 cases across 115 non-endemic countries.

The clade I variant of mpox is characterized by more severe clinical outcomes and a higher case fatality rate. The recently identified clade Ib variant, exhibiting enhanced transmissibility through close contact, has led to an increase in cases, particularly in Central Africa, and a sizable impact on children and families. According to the WHO, clade I mpox tends to cause a higher number of severe infections and have a higher mortality rate than clade II mpox.