The Food and Drug Administration (FDA) has approved Jynneos (smallpox and monkeypox vaccine, live, non-replicating; Bavarian Nordic) for the prevention of smallpox and monkeypox in adults 18 years of age and older determined to be at high risk for these infections.

Jynneos is a live vaccine produced from the strain Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN), an attenuated, non-replicating orthopoxvirus; this modified form of the vaccinia virus does not cause disease in humans and cannot reproduce in human cells. 

Vaccine effectiveness against smallpox was inferred by comparing the immunogenicity of Jynneos to a licensed smallpox vaccine (ACAM2000). In the study, immune response with Jynneos (2 doses administered 28 days apart) was found to be noninferior to the comparator vaccine (1 dose) in healthy participants with no vaccination history for smallpox

The effectiveness of the vaccine against monkeypox was inferred from antibody responses in the smallpox clinical study as well as from studies of non-human primates who were exposed to the monkeypox virus following vaccination with Jynneos.

With regard to safety, the most common adverse reactions in vaccine-naïve healthy adults were injection site reactions (ie, pain, redness, swelling, induration, and itching), muscle pain, headache, fatigue, nausea, myalgia, and chills. The frequencies of local and systemic adverse reactions among adults with HIV infection and adults with atopic dermatitis were observed to be generally similar to those seen in healthy adults.

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“Routine vaccination of the American public [against smallpox] 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,” said 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. Today’s approval reflects the US government’s commitment to preparedness through support for the development of safe and effective vaccines, therapeutics, and other medical countermeasures.”

The vaccine is supplied in 0.5mL single-dose vials and is available to those deemed to be at highest risk of infection. The vaccine is part of the Strategic National Stockpile, which ensures that life-saving drugs and medical supplies are available for use in public health emergencies.

For more information visit bavarian-nordic.com.

This article originally appeared on MPR