The FDA has approved live, non-replicating Jynneos Smallpox and Monkeypox Vaccine to prevent smallpox and monkeypox disease in adults 18 years and older who are determined to be at high risk for either infection.
The new vaccine, manufactured by Bavarian Nordic A/S, is currently the only FDA-approved vaccine for the prevention of monkeypox disease, FDA said in a press release.
Jynneos will be available for those determined to be at high risk of either smallpox or monkeypox infection. The vaccine is also part of the Strategic National Stockpile (SNS)—the nation’s largest reserve of potentially life-saving pharmaceuticals and medical supplies for use in a public health emergency severe enough to cause local supplies to be depleted.
The safety of Jynneos was assessed in more than 7,800 individuals who received at least one dose of the vaccine. The most commonly reported side effects were pain, redness, swelling, itching, firmness at the injection site, muscle pain, headache and fatigue. “No safety concerns that would require a Medication Guide have been identified for Jynneos,” the FDA says.
The vaccine is administered in two doses given four weeks apart.
Jynneos does not contain the viruses that cause smallpox or monkeypox, the FDA says. It is made from a vaccinia virus—a virus that is closely related to, but less harmful than, variola or monkeypox viruses and can protect against both of these diseases. Jynneos contains a modified form of the vaccinia virus called Modified Vaccinia Ankara, which does not cause disease in humans and is non-replicating in mammalian cells.
Following the global Smallpox Eradication Program, the World Health Organization certified the eradication of naturally occurring smallpox disease in 1980. Routine vaccination of the American public was stopped in 1972 after the disease was eradicated in the US and, as a result, a large proportion of the US, as well as the global population, has no immunity, says Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research.
“Therefore, although naturally occurring smallpox disease is no longer a global threat, the intentional release of this highly contagious virus could have a devastating effect,” Marks says.
Smallpox, which is caused by the variola virus, emerged in human populations thousands of years ago and is a highly contagious and often fatal infectious disease. A person infected with smallpox typically develops a rash characterized by raised pocks on the face and body, the FDA says. The smallpox virus is spread through saliva and droplets from the respiratory tract or by direct or indirect contact with the virus as it is shed from skin lesions. The virus can also be spread through other body fluids and contaminated clothing or bed linen. If a person is infected with smallpox and they are in close contact with others, the virus can spread quickly.
Monkeypox, which does not occur naturally in the U.S., is a rare disease caused by infection with monkeypox virus, which causes symptoms similar to, but milder than, smallpox. Monkeypox begins with fever, headache, muscle aches and exhaustion and can be fatal, even though it is typically milder than smallpox.
It is transmitted to people from various wild animals, such as rodents and primates. In 2003, the U.S. experienced an outbreak of monkeypox, which was the first time human monkeypox was reported outside of Africa.