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Cosmos Study - Collaboration

NEJM: Vaccine Effectiveness of JYNNEOS against Mpox Disease in the United States

May 18, 2023
Nicholas P. Deputy, Ph.D. | Joseph Deckert, Ph.D. | Anna N. Chard, Ph.D. | Neil Sandberg, M.S. | Danielle L. Moulia, M.P.H. | Eric Barkley, B.S. | Alexandra F. Dalton, Ph.D. | Cory Sweet, M.S. | Amanda C. Cohn, M.D. | David R. Little, M.D. | Adam L. Cohen, M.D. | Danessa Sandmann, M.P.H. | Daniel C. Payne, Ph.D. | Jacqueline L. Gerhart, M.D. | Leora R. Feldstein, Ph.D.

Key Findings

  • Two in three Mpox cases prevented in patients fully vaccinated with JYNNEOS. 
  • Even one dose of JYNNEOS provided some protection against Mpox infection. 

Review the full article at The New England Journal of Medicine. 

Summary 

Back in early January 2023, we shared preliminary findings of vaccine effectiveness for JYNNEOS in preventing Mpox disease based on our collaboration with Centers for Disease Control and Prevention. The finalized data from our investigation on vaccine effectiveness for JYNNEOS has now been published in The New England Journal of Medicine.  

Our findings confirm the preliminary data from Epic Cosmos that a two-dose vaccine series of JYNNEOS prevents medically-attended Mpox in two-thirds of patients (66.0%). One dose of JYNNEOS provides some protection, preventing Mpox infection in 35.8% of partially vaccinated patients.

Figure 1
JYNNEOS Vaccine Effectiveness Rates for Partially and Fully Vaccinated Patients
JYNNEOS Vaccine Effectiveness Rates for Partially and Fully Vaccinated Patients
Figure 1. JYNNEOS vaccine effectiveness (VE) rates for medically-attended Mpox for fully-vaccinated and partially-vaccinated patients.

Patients without an immunocompromising condition were less likely to have an Mpox infection after both one and two doses of JYNNEOS.  

You can read the full study at The New England Journal of Medicine.  

To review our previous findings and breakdowns by vaccination route of administration, see our previous publication.  

Special thanks to our collaborators at the CDC: Nicholas Deputy, Anna Chard, Danielle Moulia, Alexandra Dalton, Amanda Cohn, Adam Cohen, Daniel Payne, and Leora Feldstein.