U.S. Government Expands Mpox Vaccine Stockpile With $144 Million Order for Freeze-Dried Jynneos

The U.S. government is bolstering its emergency vaccine reserves with a $144 million purchase of a freeze-dried version of the Jynneos vaccine, designed to protect against both mpox (also known as monkeypox) and smallpox. Danish pharmaceutical company Bavarian Nordic A/S, the vaccine’s manufacturer, announced it will begin production and supply in 2026.^{1 2}

Freeze-Dried Vaccine Offers Logistical Benefits Over Liquid-Dried

The multi-million-dollar contract with Bavarian Nordic was awarded in 2017 by the U.S. Department of Health and Human Services’ (DHHS) Biomedical Advanced Research and Development Authority (BARDA) and Jynneos is one of two U.S. Food and Drug Administration (FDA) approved vaccines for the prevention of smallpox and mpox in a broader preparedness effort by DHHS to rapidly respond in the event of a smallpox outbreak. The freeze-dried version of Jynneos, approved by FDA in March 2025 is different from the the older liquid-frozen formulation and offers easier storage, longer shelf life, and simpler transportation. Both versions contain a live attenuated non-replicating orthopox virus produced from the strain Modified Vaccinia Ankara-Bavarian Nordic (MVA_BN).^{1 2}

Both versions contain a live attenuated non-replicating orthopox virus produced from the strain Modified Vaccinia Ankara-Bavarian Nordic (MVA_BN).³ Initial approval: 2019.

Since 2010, Bavarian Nordic has supplied the U.S. with the liquid-frozen formulation of Jynneos. The company ramped up production following mpox outbreaks in 2022.²

Mpox Symptoms Milder than Smallpox

There are two types of the orthopox virus that causes mpox, known as clade I and clade II. According to the U.S. Centers for Disease Control and Prevention (CDC), only four mpox cases have been reported in the United States since the 2022 outbreak, all attributed to clade I of the virus. Mpox remains a rare disease, generally presenting with milder symptoms than smallpox.⁴

“We applaud the U.S. government’s steadfast commitment to improving national health security through the exercise of these options,” Bavarian Nordic president and CEO Paul Chaplin stated in a company press release.^{1 2}

The FDA’s approval of the freeze-dried formulation was based primarily on results from a Phase II clinical trial involving 651 healthy adults. Participants received two doses of either the freeze-dried or liquid formulation. The trial found no significant difference in immune response or serious adverse effects, though the freeze-dried group reported slightly higher rates of localized reactions such as pain, swelling, and itching.^{5 6}

There is No CDC Recommendation for Routine Smallpox or Mpox Vaccination

Currently, neither mpox nor smallpox vaccines are part of routine U.S. immunization schedules. The Jynneos vaccine is used as post-exposure prophylaxis for individuals who have been exposed to mpox or are at elevated risk for being infected with mpox, such as certain healthcare or laboratory workers. Routine smallpox vaccination ended in the U.S. in the 1970s but remains recommended for specific high-risk occupations, according to the CDC’s Advisory Committee on Immunization Practices (ACIP).⁷

The CDC also advises individuals—particularly young males at increased risk of myocarditis—to wait four weeks after receiving the Jynneos vaccine before getting certain COVID-19 shots.⁸

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