National Center for Emerging and Zoonotic Infectious Diseases

Mpox Vaccine Work Group

ACIP Meeting

June 23, 2023

Pablo Sanchez MD

The Ohio State University−Nationwide Children’s Hospital

Chair, ACIP Mpox Work Group
Mpox outbreaks

▪ Before 2022, rare outside of Africa

▪ In Africa, have involved 2 clades:

– Clade I (previously Congo Basin Clade)

– Clade II (previously West African Clade)

▪ In United States, have involved Clade II

– Clade IIa: 2003 U.S. outbreak associated with pet prairie dogs

– Clade IIb: 2022/2023 global outbreak associated with male-to-male 

sexual contact

▪ Historically: Clade I believed to be associated with more severe disease 

than Clade II
Severe manifestations observed in severely 

immunocompromised persons during the 2022/2023 outbreak: 

Clade IIb

Carrubba S, Geevarghese A, Solli E et al. Novel severe oculocutaneous manifestations of human 

monkeypox virus infection and their historical analogues. Lancet Infect Dis. 2023 Jan 23:S1473-

3099(22)00869-6. 

Menezes YR, Miranda AB. Severe disseminated clinical 

presentation of monkeypox virus infection in an 

immunosuppressed patient: first death report in Brazil. Rev Soc 

Bras Med Trop. 2022 Aug 29;55:e0392. 
ACIP recommendations

▪ With global eradication of smallpox, routine vaccinations against 

orthopoxviruses were no longer needed

▪ Routine smallpox vaccinations stopped globally in 1980 (USA, 1972)

▪ ACIP recommendations for persons at occupational risk for orthopoxvirus

infections since 1980

– Largest proportion of people recommended to be vaccinated are 

research laboratorians who work with orthopoxviruses (including 

monkeypox virus [MPXV])

– ACAM2000 and JYNNEOS are the vaccines recommended
Current ACIP recommendations for persons at risk for 

occupational exposure: ACAM2000 and JYNNEOS

▪ Since 2015, ACAM2000 recommended 

▪ In November 2021, JYNNEOS recommended as alternative to ACAM2000
ACAM2000 compared to JYNNEOS

ACAM2000 JYNNEOS

Vaccine virus Live, replication competent vaccinia 

virus

Live, replication deficient vaccinia 

virus

Administration Via multiple percutaneous puncture 

technique (single dose)

Subcutaneously* via 2 vaccine doses, 

28 days apart

Take Inadvertent inoculation and 

autoinoculation can occur via vaccine 

site lesion

No risk of inadvertent inoculation 

and autoinoculation with vaccinia 

virus

*During the 2022/2023, intradermal was the preferred route of administration; vaccine effectiveness data 

indicates this route has been equally effective 
Contraindications for ACAM2000 and JYNNEOS
2022/2023 U.S. mpox outbreak: JYNNEOS 

recommended

▪ Fewer contraindications and adverse events with JYNNEOS

▪ Before this outbreak, no real-world experience with JYNNEOS

https://www.cdc.gov/poxvirus/mpox/vaccines/index.html
Short-term goal of the Work Group

▪ Currently no ACIP recommendation for use of JYNNEOS during mpox

outbreaks

▪ Develop ACIP recommendations for use of JYNNEOS during mpox

outbreaks*

* Public health authorities determine whether there is an mpox outbreak; a single case may be 

considered an mpox outbreak at the discretion of public health authorities. Other circumstances in 

which a public health response may be indicated include ongoing risk of introduction of mpox into a 

community due to disease activity in another geographic area.
February 2023 ACIP meeting: Vote passed for use of 

JYNNEOS during outbreaks

ACIP recommends the 2-dose* JYNNEOS vaccine series for persons 

aged 18 years and older at risk of mpox during an mpox outbreak §

*Dose 2 administered one month after dose 1

§ Public health authorities determine whether there is an mpox outbreak; a single case may be 

considered an mpox outbreak at the discretion of public health authorities. Other circumstances 

in which a public health response may be indicated include ongoing risk of introduction of mpox

into a community due to disease activity in another geographic area.
Timeline that was proposed during February 2023*

Mpox outbreaks: Use of 2-

dose JYNNEOS for persons 

aged ≥ 18 years

February 2023 June 2023 October 2023

-Mpox outbreaks: Use of 2-dose JYNNEOS

for persons aged <18 years 

-Updates about vaccine effectiveness and 

safety

Consider need for longer term 

vaccination strategy for 2-dose 

JYNNEOS

*These votes do not impact existing recommendations for the current mpox outbreak. 

§ https://www.cdc.gov/poxvirus/monkeypox/interim-considerations/overview.html
Agenda for today’s meeting

▪ Updates about epidemiology, vaccine safety, and vaccine effectiveness 

during the ongoing outbreak: Faisal Minhaj

▪ Clinical guidance about the use of 2-dose JYNNEOS (subcutaneous) series 

during mpox outbreaks: Agam Rao

▪ Considerations for long-term protection against mpox: Discussion in the 

context of the ongoing outbreak: Agam Rao
Tentative timeline for ACIP discussions and votes

ACIP meeting: Clinical 

guidance about use of 

JYNNEOS during outbreak

June 2023 August/September 2023 October 2023

Publication of MMWR 

about use of JYNNEOS 

during mpox outbreaks

ACIP meeting: Consider need 

for longer term vaccination 

strategy for 2-dose JYNNEOS

Current U.S. mpox vaccination strategy remains in effect

Current US mpox vaccination strategy remains active: Populations at high 

risk should continue to be vaccinated *

*MMWR publication will not change the clinical guidance posted for the ongoing outbreak: 

https://www.cdc.gov/poxvirus/monkeypox/interim-considerations/overview.html
WG members

ACIP Member

Pablo Sánchez

Beth Bell 

Ex Officio and Liaison Members

CSTE: Chris Hahn / Paul Cieslak

ASTHO: Ericka McGowan

NACHO: Philip Huang

FDA: Sixun Yang, Clement 

Meseda & Alonzo García

ACOG: Howard Minkoff

AAP: Jim Campbell

AIM: Rob Schechter / Jane Zucker

APHL: Jafar Razeq

NIH: Janet Lathey / Kimberly Taylor 

IHS: Matthew Clark

NACI: Nicole Forbes / Oliver Baclic

IDSA: Shireesha Dhanireddy / Rajesh Gandhi

Invited Consultants

Subject matter experts: Inger Damon, Stuart 

Isaacs, Mike Merchlinsky & Amanda 

Zarrabian (HHS/BARDA)

Clinician experts in STIs, HIV, pediatrics, 

maternal vaccination, vaccine safety, health 

equity, smallpox vaccination strategies, 

occupational health
Clinician experts

STIs, HIV, and mpox

(adult and peds):

Jason Zucker

Jeanne Marrazzo

Pablo Tebas

Vince Marconi

Kim Workowski

Bonnie Maldonado

Immunizations (including for special 

populations) and vaccine safety:

Ruth Karron

Flor Munoz-Rivas

Kathy Edwards

Health equity, vaccination strategies 

including for smallpox:

Joel Breman

Gerard Vong

Occupational Medicine and worker safety:

Mark Russi
CDC contributors

Mpox epi, lab, and vaccine experts

Brett Petersen

Andrea McCollum

Christy Hutson

Laboratory Response Network:

Julie Villanueva

Infection control, worker safety:

Marie de Perio

David Kuhar

Special populations (e.g., Persons 

experiencing homelessness)

Emily Mosites

Vaccine safety

Michael McNeil

Jonathan Duffy

Regulatory Affairs

Yon Yu

STIs and HIV

Laura Bachmann

Leandro Mena

John Brooks 

Alexa Oster

Drug Services

Julian Jolly

Vaccine 

implementation

Liz Velasquez

James Lee

DoD Liaison to CDC

Alan Lam

Work group lead 

Agam Rao
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you!