Amanda B. Payne, PhD1; Logan C. Ray, MPH1; Matthew M. Cole, MPH1; Michelle Canning, MPH1; Kennedy Houck, MPH1; Hazel J. Shah, MPH1; Jennifer L. Farrar, MPH1; Nathaniel M. Lewis, PhD1; Amy Fothergill, PhD1,2; Elizabeth B. White, PhD1,2; Leora R. Feldstein, PhD1; Lauren E. Roper, MPH1; Florence Lee, MPH1; Jennifer L. Kriss, PhD1; Emily Sims, MPH1; Ian H. Spicknall, PhD1; Yoshinori Nakazawa, PhD1; Adi V. Gundlapalli, MD, PhD1; Tom Shimabukuro, MD1; Adam L. Cohen, MD1; Margaret A. Honein, PhD1; Jonathan Mermin, MD1; Daniel C. Payne, PhD

Among JYNNEOS vaccine-eligible men aged 18–49 years in 43 U.S. jurisdictions, mpox incidence among unvaccinated persons was 9.6 times as high as that among persons who had received 2 vaccine doses and 7.4 times as high as that among persons who had received only the first dose. Preliminary evidence indicates no difference in protection between subcutaneous and intradermal administration routes.

This report describes a recent finding that mpox incidence among unvaccinated men aged 18–49 years was 10 times as high as vaccinated men who received both JYNNEOS doses.