FDA Approves Expanded Use of ACAM2000 for Monkeypox Prevention

The FDA has granted a supplemental biologics license application to expand the indication for ACAM2000 to include Monkeypox disease prevention in high-risk people, according to a news release from developer Emergent BioSolutions.

Previously, the only indication was to prevent smallpox.

What is ACAM2000?

Existing human safety data and animal research show the vaccine’s effectiveness against Monkeypox virus exposure. It comes after Emergent submitted an expression of interest to the WHO for the emergency use listing of ACAM2000 to treat the ongoing mpox outbreak, which was declared a public health emergency of international concern by the organization on August 14.

“The FDA approval of ACAM2000 for immunization against Monkeypox 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, in a statement.

“This new indication for ACAM2000 comes at a critical time, as the global health community works to guarantee an effective and coordinated response to the recent increase in Monkeypox cases.

We believe Emergent is well-positioned to support the global response by actively engaging with world health leaders and deploying goods presently in inventory based on needs, as well as the ability to enhance supply.”

ACAM2000 is a one-time skin-prick vaccine delivered percutaneously with a bifurcated needle dipped in vaccine solution.

In 2022, the World Health Organization proclaimed the first Monkeypox public health emergency of international concern, resulting in the spread of over 95,000 cases over 115 non-endemic areas.

The initial emergency was caused by clade II mpox, which has a 99.9% survival rate. However, the present emergency is caused by the newer clade 1b strain.

Expert Opinions on ACAM2000 and Monkeypox

According to WHO, clade I causes more severe infections and has a greater fatality rate than clade II. Because the majority of cases are concentrated in Central Africa, infection and mortality rates in the Democratic Republic of Congo have already exceeded last year’s total, with over 15,600 cases and 537 deaths reported.

The majority of human-to-human Monkeypox transmission has occurred in households, health care settings, and through sexual contact, particularly between men who have sex with men and sex workers.

However, the fact that the majority of cases and deaths in the current Monkeypox outbreak are in minors implies that transmission occurs via ways other than sexual contact. Effective outbreak management requires better surveillance, testing, contact tracing, and public health measures.

Emergent BioSolutions has announced that it will give 50,000 doses of ACAM2000 for potential use in affected areas.

“Monkeypox 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 Amesh A.

Adalja, MD, FIDSA, FACP, FACEP, and health security and emerging infectious disease expert at Johns Hopkins Centre for Health Security, in the same release.

“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.”

Currently, ACAM2000 is the primary smallpox vaccination approved for use in bioterrorism emergencies. It is also licensed in Canada, Australia, and Singapore, with stockpiles in the United States and across the world.