The approval of Jynneos Smallpox and Monkeypox Vaccine, Live, Non-Replicating, for the prevention of smallpox and monkeypox disease in adults (18 years of age and older) determined to be at high risk for smallpox or monkeypox infection was announced by the U.S. Food and Drug Administration. For the prevention of monkeypox disease, this is the only currently FDA-approved vaccine. Jynneos will be available for those who are determined to be at high risk of either smallpox or monkeypox infection. This vaccine is also
part of the Strategic National Stockpile (SNS), the nation’s largest supply of potentially lifesaving pharmaceuticals and medical supplies for use in a public health emergency that is severe enough to cause local supplies to be depleted. In the SNS, the availability of this vaccine will help ensure that the vaccine is accessible in the U.S. if needed.
Caused by the variola virus, Smallpox emerged in human populations thousands of years ago and is highly contagious and often fatal infectious disease. Monkeypox is a rare disease which does not naturally occur in the U.S and is caused by infection with monkeypox virus, which causes symptoms similar to but milder than smallpox.
Viruses that cause smallpox or monkeypox are not contained in Jynneos. It is made from a vaccinia virus. This is a virus which is closely related to but is less harmful than variola or monkeypox viruses and has the ability to protect against both of these diseases. Jynneos contains a modified form of the vaccinia virus called Modified Vaccinia Ankara. This virus does not cause disease in humans and is no-replicating, which means that it cannot reproduce in human cells.
In a clinical study, the effectiveness of Jynneos for the prevention of smallpox was determined while comparing the immune responses in study participants who received either Jynneos or ACAM2000.
The effectiveness of Jynneos for the prevention of monkeypox disease is inferred from the antibody responses in the smallpox clinical study participants and from studies in non-human primates that showed protection of animals vaccinated with Jynneos who were exposed to the monkeypox virus.