A transmission electron micrograph of smallpox viruses.
Smallpox is a disfiguring and deadly disease caused by the variola virus. In 1980, the World Health Organization declared that smallpox had been eradicated worldwide. However, smallpox continues to concern public health officials as a potential biological weapon.
A vaccine known as Dryvax was instrumental to achieving smallpox eradication, and the United States has enough of its successor, ACAM2000, on hand to vaccinate the population in case of a terrorist attack. However, people with weakened immune systems or skin conditions like atopic dermatitis are at increased risk for serious side effects from these vaccines.
NIAID recognized the need for a safer smallpox vaccine that could be used to protect patients with weakened immune systems, like those with HIV or cancer. With this goal, NIAID invested in the development of a second-generation vaccine using Modified Vaccinia Ankara (MVA), a highly weakened vaccinia virus that does not replicate well in humans. The MVA vaccine was developed by Bavarian Nordic.
NIAID supported early advanced development work for this important vaccine. This included toxicology and efficacy studies to enable investigational new drug (IND) status and clinical trials in individuals infected with HIV and atopic dermatitis. NIAID also supported preclinical studies on animal model development, natural history, virulence, and vaccine efficacy which led to the successful development of MVA.
In 2013, Canada and the European Union approved MVA (under the trade names IMVAMUNE® and IMVANEX®) for use in the general population, including people with weakened immune systems or atopic dermatitis. In 2019, the U.S. Food and Drug Administration (FDA) approved MVA-BN, a modified version of the original MVA vaccine also known as JYNNEOS, for the prevention of both smallpox and monkeypox in adults. This vaccine is part of the U.S. Strategic National Stockpile (SNS), the nation’s largest supply of potentially life-saving pharmaceuticals and medical supplies for use in a public health emergency.