FDA Approves Smallpox/Monkeypox Vaccine

The FDA has approved Jynneos, a new live, non-replicating vaccination for the prevention of smallpox and monkeypox in adults aged 18 years and older who are at high risk for the diseases. This is the only currently approved vaccine for the prevention of monkeypox.

The vaccine does not contain the smallpox or monkeypox viruses, but instead is made from a vaccinia virus which does not cause disease in humans.

The vaccine’s effectiveness was tested in a clinical study comparing its effects with those of ACAM2000, an FDA-approved vaccine for the prevention of smallpox. The 400 participants in the study received either 2 doses of Jynneos 28 days apart or a single dose of ACAM2000. The immune response in the group given Jynneos was not inferior to those in patients who received ACAM2000.

The vaccine’s effectiveness for the prevention of monkeypox was inferred from antibody responses in the smallpox study and from non-human primate studies.

The safety of the vaccine was evaluated in over 7800 individuals who had received at least one dose of the vaccine. The most common side effects were pain, redness, swelling, itching, firmness at the injection site, muscle pain, headache, and fatigue.

—Michael Potts

Reference:

FDA approves first live, non-replicating vaccine to prevent smallpox and monkeypox [press release]. September 24, 2019. https://www.fda.gov/news-events/press-announcements/fda-approves-first-live-non-replicating-vaccine-prevent-smallpox-and-monkeypox.