​ JYNNEOS was made available in Australia under Section 18A of the Therapeutic Goods Act 1989 (Cth) from August 2022 and can only be administered when consent is obtained and ordered by a medical practitioner at a site authorised by the Chief Health Officer.

JYNNEOS is the preferred vaccine for post-exposure prophylaxis (PEP) for medium and high-risk contacts of a confirmed or probable case in NSW due to its favourable safety profile and ease of administration.

The process for determining suitability for PEP should be through a shared decision-making process between the patient and clinician alongside a discussion with the local Public Health Unit. Factors to consider may include individual risk factors for severe mpox infection, absolute or relative contraindications to vaccination, prior vaccination with an mpox or smallpox vaccine, date of last contact, and ongoing risk of exposure.

PEP should be considered as soon as possible after exposure to a confirmed or probable mpox case, ideally within 4 days of exposure, although administration up to 14 days can be considered as it may attenuate disease severity.

For the purposes of PEP, a single dose of 0.5mL (subcutaneous) is required for protection against contracting mpox infection and attenuating disease/symptoms. If mpox has not occurred and there is a significant ongoing risk, a second dose of JYNNEOS may be considered at least 28 days after the first dose as completion of a primary course for long-term protection.

Any medium or high-risk contacts who have received two doses of the JYNNEOS vaccine do not require PEP after being exposed to mpox.

How to access PEP

During active phases of vaccine roll-out

Public Health Units may refer medium or high risk contacts to their nearest publicly funded sexual health service offering JYNNEOS that can be used for PEP.

The NSW Biocontainment Unit (NBCU) at Westmead Hospital and three s100 GP practices also have a supply of JYNNEOS that can be used for PEP.

Public Health Units should contact the publicly funded sexual health services (PFSHS), s100 GP or NBCU directly to confirm that JYNNEOS is available and request assessment of the close contact by the PFSHS/GP/NBCU as soon as possible.

For close contacts not readily able to access the clinics above, or if clinics do not have any JYNNEOS on site, follow option 2.

Local vaccine stock not available

When close contacts are not able to access a clinic with JYNNEOS stock, the Public Health Unit should order vaccine from the State Vaccine Centre (see 4. Ordering vaccine from the State Vaccine Centre).

Public Health Units should consider the following factors in determining where/when vaccine should be ordered:

• JYNNEOS can only be distributed in boxes of 20 doses
• Once thawed, JYNNEOS must be kept at 2-8°C, and must only be drawn up immediately before use
• Stock from the State Vaccine Centre has been thawed from -50°C to 2-8°C and may be kept at 2-8°C for 24 weeks, and if not used by then, discarded.

Weekend and public holiday arrangements

When PEP is due before the next opening hours of a PFSHS, Public Health Units have the following options:

• NSW Biocontainment Unit – ID physician on-call 24/7 via Westmead switch
• Kirketon Road Centre – open Saturday and Sunday mornings
• Taylor Square Private Clinic, East Sydney Doctors and Holdsworth House (Darlinghurst & Surry Hills). Variable weekend hours. Billing arrangements to be discussed with each practice.
• Local Health District (LHD) facility – this should be pre-negotiated with the LHD Director of Clinical Governance and the facility General Manager to ensure that appropriate pathways are pre-identified to ensure that there are separate patient waiting areas, streamlined administration to reduce risk of transmission, and follow up pathways. This may be a local Emergency Department. Additional health care (e.g., STI screen) should be part of the inhours follow up of patients.

Ordering vaccine from the State Vaccine Centre

Vaccine should only be ordered from the State Vaccine Centre when at-risk contacts are not able to access vaccine from a  sexual health clinic.

The process of ordering and administration of vaccine should be as follows:

• Public Health Unit to get Director approval prior to ordering the vaccine
• Public Health Unit orders from State Vaccine Centre
• Public Health Unit to advise administering facility when to expect delivery (delivery of vaccine will come as a package of 20 vials)
• Administering facility advises Public Health Unit that delivery has arrived
• Contact attends administering facility and is reviewed by medical officer or nurse practitioner and vaccine ordered and administered
• Administering facility advises Public Health Unit that dose has been received by contact
• Administering facility or Public Health Unit to record dose in the Australian Immunisation Register (local arrangement)
• Remaining 19 vials of vaccine to be refrigerated at 2-8°C in original package.

Next business day, the Public Health Unit needs to arrange with the pharmacy to transport the remaining vaccine in its original package to the local sexual health clinic, and email  MOH-CDBSpecialistPrograms@health.nsw.gov.au with the contact information and site where the remaining vaccine has been sent.

Special circumstances: PEP vaccination of children

The Australian Technical Advisory Group on Immunisation (ATAGI) advises that vaccination with JYNNEOS in children can be considered, especially for individuals in high-risk groups aged 16 years and older, after discussing the risks and benefits of vaccination with their immunisation provider.

In the case of a contact aged under 18 years requiring PEP vaccination, Public Health Units may refer to the South Eastern Sydney LHD process for arranging PEP for children. Vaccination is likely most appropriate via the Emergency Department of a children’s hospital, in discussion with the infectious diseases consultant on-call. However, contacts aged 16 years or older may be able to be vaccinated at existing mpox vaccination clinics.