The FDA has expanded approval for Emergent BioSolutions' smallpox vaccine, ACAM2000, to include prevention of Mpox in high-risk individuals. This makes it the second approved Mpox vaccine in the U.S., alongside Bavarian Nordic's Jynneos. However, ACAM2000 has limitations for immunocompromised individuals and requires a unique administration method.
Key Findings
ACAM2000 is now FDA-approved for Mpox prevention in high-risk individuals
It joins Jynneos as the second approved Mpox vaccine in the U.S.
ACAM2000 cannot be administered to immunocompromised individuals, including those with HIV
The vaccine is administered through small skin pricks using a two-pronged needle
A new Mpox strain, clade Ib, is rapidly spreading in Africa
The WHO has declared Mpox a global public health emergency for the second time in two years
How It Works
ACAM2000 is a live vaccinia virus vaccine. It triggers a localized immune response at the injection site by introducing a live, but non-replicating, form of the virus, prompting the immune system to develop long-term protection. It’s administered through a bifurcated needle, which creates multiple skin punctures, resulting in a scab that must heal to avoid spreading the live virus.
Why This Matters
The expanded approval of ACAM2000 provides an additional tool for Mpox prevention, especially important given the recent global health emergency declaration. However, its limitations for immunocompromised individuals and unique administration method may impact its widespread use.
In Practice
Healthcare providers should be aware of ACAM2000's approval for Mpox prevention but also understand its contraindications for immunocompromised patients. The unique administration method requires specific training and patient education to ensure proper use and prevent accidental spread of the live virus.
Beyond the Headline
While ACAM2000's approval expands prevention options, its limited use during the 2022 mpox outbreak, despite being part of the U.S. stockpile, raises questions about its practical application. The vaccine's potential role in addressing the new Mpox strain (clade Ib) spreading in Africa remains to be seen.
Big Picture
This approval comes amid a complex global health landscape, with Mpox resurgence and new strain emergence. It highlights the ongoing need for diverse vaccine options and the challenges of balancing efficacy, safety, and practicality in vaccine development and distribution.
Ethical Considerations
The vaccine's contraindication for immunocompromised individuals, including those with HIV, raises ethical questions about equitable access to preventive measures. This limitation underscores the need for diverse vaccine options to protect all population groups effectively.
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