US FDA approves ACAM2000 vaccine to prevent monkeypox for people at high risk of the disease

According to the FDA, ACAM2000 is a live attenuated vaccine, but it can cause side effects. On average, 1 in 175 people who receive the ACAM2000 vaccine will develop myocarditis or pericarditis.

The FDA's latest decision comes after Emergent BioSolutions submitted an application to the World Health Organization (WHO) to list the ACAM2000 vaccine for emergency use.

Live vaccines like ACAM2000 are vaccines made from pathogens (viruses or bacteria) that are still alive but have been weakened. These weakened agents, when injected into the body, will remain active and continue to multiply to form a population sufficient to stimulate the immune system to develop antibodies, helping the body build immunity. When encountering bacteria or viruses again in the future, the vaccinated immune system will be able to recognize and destroy the pathogen, helping to prevent infection or, if infected, will not progress to a serious stage. Regarding the method of vaccination, instead of one injection like conventional vaccines, the ACAM2000 vaccine is injected through a series of small punctures on the skin with a 2-needle needle, creating a scar. About 2 to 4 weeks after injection, the scar will heal. During that time, the weakened live virus can spread throughout the body, strengthening the immune system. However, the FDA recommends that the ACAM2000 vaccine not be given to people with weakened immune systems, such as people with HIV.

Earlier this August, the WHO declared a global public health emergency due to an outbreak of monkeypox in African countries. The new variant of the virus, Clade 1b, has caused the disease to spread rapidly there.

Last week, Emergent announced it would donate 50,000 doses of its smallpox vaccine to the Democratic Republic of Congo and other affected countries including Burundi, Kenya, Rwanda and Uganda to help contain the current monkeypox outbreak.