United States of America (Vax-Before-Travel News)
With the World Health Organization announcing that the mpox upsurge continues to meet the criteria of a public health emergency of international concern, many vaccinated individuals are seeking advice on obtaining a third dose (booster).
While France’s High Authority for Health (HAS) announced a booster strategy in September 2024, the United States has been reluctant to follow suit.
HAS suggests that a mpox booster dose is associated with longer antibody persistence than after a single two-dose primary vaccination. It therefore recommends a single booster dose for people who received their vaccination in 2022, and this recommendation varies depending on whether they are immunocompromised and their history of infection.
Currently, the U.S. Centers for Disease Control and Prevention (CDC) states that the JYNNEOS vaccine is licensed to prevent smallpox and mpox and is recommended by the Advisory Committee on Immunization Practices as a two-dose primary series for specific individuals at risk of exposure to orthopoxvirus infections, including mpox.
As of June 2025, the CDC says ‘Even when infections have occurred after two vaccine doses, they have typically been milder than the infections among people who are not vaccinated. And does not generally recommend a third dose.’
However, a new preprint study’s findings may prompt a change in the CDC’s stance.
On June 6, 2025, a comprehensive study assessed the safety and long-term immunological response of MVA-BN (JYNNEOS) vaccination in Africa. It concluded that MVA-BN vaccination induces sustained immunological memory after primary vaccination for up to five years post-vaccination.
But, when a third (booster) dose is added, reactogenicity increases significantly compared to the primary two-dose series.
In comparison to primary vaccination, only one confirmed (Breakthrough) case of mpox was identified.
Since 2022, MVA-BN has been widely administered in high-income countries, with over 1.2 million doses administered in the USA.
With mpox cases being reported in 122 countries, including 115 countries where mpox was not previously reported, additional vaccinations are expected.
The majority of U.S. cases of clade II mpox continue to be in people who are not vaccinated or who have only received one dose of JYNNEOS.
As of June 11, 2025, JYNNEOS is commercially offered at various clinics and pharmacies, often supported by insurance coverage.
