Emergent BioSolutions announced on Monday that it would donate 50,000 doses of its smallpox vaccine, ACAM2000, to the Democratic Republic of the Congo, Burundi, Kenya, Rwanda, and Uganda to help combat the ongoing mpox outbreak.

The World Health Organization recently declared mpox a global public health emergency for the second time in two years, following the rapid spread of a new variant, clade Ib, across Africa. This variant has also been detected outside the continent, with a confirmed case in Sweden.

PHOTO | COURTESY mpox outbreak

Although the ACAM2000 vaccine is approved for smallpox, it has also been used off-label for mpox. However, the U.S. Food and Drug Administration has not approved it specifically for mpox treatment.

According to the U.S. Centers for Disease Control and Prevention, ACAM2000, a live, replicating virus vaccine, carries more risks and side effects than Bavarian Nordic A/S's Jynneos vaccine, which is FDA-approved for both smallpox and mpox.

PHOTO | COURTESY mpox outbreak

One of the known risks associated with ACAM2000 is myocarditis or pericarditis, which occurs in about 1 in 175 recipients. Unlike traditional injections, ACAM2000 is administered through multiple pricks on the skin using a two-pronged needle, forming a scab that takes 2-4 weeks to heal.

The live virus can spread to other body parts or individuals during this period. Due to these risks, ACAM2000 is not recommended for people with compromised immune systems, including those with HIV.