Schedule

2 doses of Jynneos 0.5mL (subcutaneously) separated by a minimum of 4 weeks.  

Completion of the two-dose series should be encouraged to ensure longer lasting immunity. Delays in administering the second dose do not require restarting the series.

‍Pre-exposure
‍Population groups considered at higher risk of exposure or further transmission, including:

• Gay, bisexual and other men who have sex with men (GBMSM), transgender or non-binary people who in the past 6 months have had one of the following:

             - A new diagnosis of a sexually transmitted disease
             - More than one sex partner
             - Sex at a commercial venue
             - Sex in association with a large public event in an area where mpox transmission is                 likely to occur

• People living with HIV, if at risk of mpox exposure

• Those at occupational risk of mpox exposure:

             - Laboratory staff working with orthopoxviruses
             - Health workers at risk of repeated exposures to patients with mpox
             - Sex workers, particularly for those with clients who are risk of exposure to mpox

• Sexual partners of those at increased risk of mpox infection

• People who anticipate experiencing any of the above.

‍

‍Post-exposure

• Close contacts of people infected with mpox (e.g., intimate partners)

• People whose occupation might put them at increased risk and if there is a breach of protective personal equipment (PPE) (i.e., healthcare workers caring for those infected with mpox and laboratory workers handling mpox swabs).

This vaccine can be given to individuals with immunocompromising medical conditions or therapy, including those living with HIV infection (PWHIV). It can also be given to those taking HIV pre-exposure prophylaxis (PrEP) medication.

This vaccine is not available for travel purposes, to areas with an active outbreak, unless the individual is at high risk of infection due to occupational or sexual activities.

‍

Administration

The current recommendation is that all doses be given via the subcutaneous (SC) route.  

If demand in NZ is higher than currently anticipated, there remains an option to revert to fractional intradermal (ID) administration.

If a vaccine course was commenced using the ID route for the first dose, it can be completed by SC route for the second dose, and vice versa.

Pre-exposure

For those aged 18 years and over, two doses of Jynneos 0.5mL is administered subcutaneously for all eligible population, separated by a minimum of 4 weeks.  

Post-exposure

• To maximise chance of preventing infection, Jynneos should be administered preferably within 4 days from date of mpox exposure.

• Asymptomatic individuals may still be offered vaccination up to 14 days after exposure to mpox with the aim of reducing severity of symptoms.

• If Jynneos vaccine is administered post-exposure and consumer remains asymptomatic then a second dose should be administered a minimum of 4 weeks after the first.  

‍Prior mpox infection
Individuals who have either been diagnosed with laboratory-confirmed mpox prior to vaccination or after the first dose are not recommended vaccination or further doses. This is because mpox infection likely confers adequate immune protection or boosts immunity in those recently vaccinated. For those with immunocompromise and diagnosed with mpox after their first dose of MPV, a second dose of MPV can be considered based on clinical judgement. For those who have received a smallpox vaccine in the past, a full two-dose course of mpox vaccine is still recommended, particularly for individuals with immunocompromise.

‍Co-administration
Due to lack of data, the datasheet currently says to avoid co-administration with other vaccines.  

Based on first principles, there is minimal risk of interference between Jynneos and other vaccines.  

Since this cohort are likely to benefit from administration of additional vaccines such as HPV and MMR, it is recommended that vaccine histories are checked and where possible co-administration of these vaccines is offered, supported by a standing order or prescription and written informed consent. If this is not possible, offer to rebook or add to recall lists.

‍Under 18 years
‍Jynneos can be considered in this age group, especially for individuals in high-risk groups and for post-exposure prophylaxis following consultation with prescriber.  A prescription and written informed consent are required.  

‍

Storage and preparation

‍

• Jynneos is provided as a single-dose vial of 0.5mL in suspension

• Vaccine supply is stored centrally at minus 50°C. It is defrosted when packaged for delivery to site and expiry date recorded on the box

• Unopened vials should be stored in their box at +2 to +8°C for up to 24 weeks (or to expiry date, whichever is sooner)

• Do not re-freeze

• On site storage +2 to +8°C

• Vaccines are prepared only as needed

• Allow vaccine to reach room temperature before use

• Before drawing up the vaccines, swirl vial gently for at least 30 seconds

• Follow guidance in IMAC factsheet “Subcutaneous (SC) vaccine preparation: mpox Jynneos” for details of preparation and administration of SC vaccines.

• Jynneos should not be given to anyone with a history of anaphylaxis to a previous dose of Jynneos or any component of the vaccine.

• Jynneos is contraindicated in subjects with known hypersensitivity to any of the vaccine’s excipients or trace residues (chicken or egg protein, gentamicin, ciprofloxacin, or benzonase). The datasheet also says, “the risk for a severe allergic reaction should be weighed against the risk for disease due to monkeypox”. It is recommended that you seek guidance from 0800IMMUNE or a prescriber.
  If vaccinated, written informed consent is required and consumer should be observed for a longer period of atleast 30 minutes following vaccination.

• Jynneos should not be given to anyone with myocarditis or pericarditis following a previous dose of Jynneos and anyone with previous myocarditis or pericarditis should have a risk-benefit discussion.  

• Postpone vaccination in individuals who are acutely unwell with a fever over 38°C. Do not delay immunisation in those with a minor infection and/or low-grade fever.

Potential responses – subcutaneous

Common adverse events in clinical trials include local site reactions: pain (85%), redness (61%), swelling (52%), induration (46%) and itching (43%); and systemic symptoms: muscle pain (43%), headache (35%), fatigue (30%), nausea (17%) and chills (10%).¹ Responses are mainly mild to moderate in intensity and resolve without intervention within seven days following vaccination.  

Frequency of adverse events, particularly local site reactions, are higher in those who have received previous live smallpox (vaccinia) immunisation.  

Active surveillance in Aotearoa New Zealand from the Post Vaccine Symptom Check (PVSC) of the Jynneos vaccine (mainly administered ID during the survey period) showed the rate of adverse events was similar or less than during clinical trials. Of the PVSC day-7 survey participants, 68% reported at least one adverse event, 4% reported missing work or other daily activities, and fewer than 2% sought medical care.  Local reactions and fatigue were most commonly reported.

Myocarditis/pericarditis

Increased risk for myocarditis (inflammation of heart muscle) and pericarditis (inflammation of lining of the heart) was shown for the older first- and second-generation live smallpox vaccines. No increase in risk has been shown with Jynneos, to date, so if there is an association it is likely to be less frequent. Since young men are at higher risk for these conditions, Medsafe continues to monitor adverse event reports closely. 

Reactogenicity in those with atopic dermatitis

Safety for those with atopic dermatitis (AD) has been investigated in a phase II study involving 345 patients with AD. Individuals with AD had more injection site-associated reactions (redness 61% vs 50%, and swelling 52% vs 41%) and generalised symptoms (headache 47% vs 35%, chills 16% vs 8%, nausea 23% vs 15% and fatigue 36% vs 27%) following SC Jynneos vaccination than healthy controls. Reactogenicity with other skin disorders has not been investigated.

Pregnancy and breastfeeding

Mpox can be severe in pregnant people and have adverse effects on the fetus. Animal toxicity studies did not identify any evidence of harm when Jynneos is given prior to or during gestation. As Jynneos is a non-replicating vaccine, adverse events would be expected to be the same as in non-pregnant people. In these situations, the risk from mpox infection to the mother and the infant should be discussed. Please contact 0800 IMMUNE for guidance, and if vaccinated written informed consent is required.  

Jynneos has not been formally evaluated in lactating people; however, there are no theoretical safety concerns relating to use while breastfeeding.

Safety in people living with HIV

Jynneos is replication defective and, unlike other live vaccines, does not pose a risk to those with immunocompromise. Large numbers of PWHIV have received the vaccine globally and are a priority group for vaccination.  Safety was carefully assessed in 91 PWHIV with CD4 counts over 350 cells/mm³ and was found to be well tolerated. However, immune response to the vaccine could be reduced in those who are severely immunocompromised.    

Under 18 years

Jynneos has not been formally studied in children under 18 years; however, there are trial data on safety in children on MVA used a as the vector for a small number of childhood vaccines and when administered MPV for pre- or post-mpox exposure during outbreaks.  

Jynneos can be considered in this age group, especially for individuals in high-risk groups and for post-exposure prophylaxis following consultation with prescriber, with a prescription and written informed consent.

Studies of antibody responses, preclinical studies and real-world data show Jynneos is most effective when given pre-exposure. Studies reported in 2022 showed good protection following one or two doses of Jynneos. A systematic review found vaccine effectiveness against mpox infection to be 76% (95% CI 64-88%) after one dose and 82% (72-92%) after two doses in predominantly GBMSM aged 18-49 years. Effectiveness is similar regardless of administration route.  

Breakthrough cases following vaccination are mostly mild with low number of lesions. Reinfection has also been described. The vaccine can decrease severity of illness, risk for hospitalisation, and even death among those who are immunocompromised.  

Further research is needed to better understand the efficacy of mpox vaccine for post-exposure prophylaxis. Current evidence shows that post-exposure vaccination offers some protection against mpox. The incidence rate of mpox in those vaccinated post-exposure was shown to be 14 times lower than those who were unvaccinated in an observational study in the US. It is likely to be most effective if given within four days of exposure, if given later it may reduce the severity of illness.

Consumers should be aware they could still contract mpox after vaccination and should consider avoiding or reducing intimate contact with people who have or may have mpox and seek medical care if they develop symptoms that could be mpox.

1. US Food and Drug Administration. JYNNEOS- FULL PRESCRIBING INFORMATION Package Insert. 2018. Available from: https://www.fda.gov/media/131078/download 

2. Arbel, R. et al, Effectiveness of a single-dose Modified Vaccinia Ankara in Human Monkeypox: an observational study DOI. Available from: https://doi.org/10.21203/rs.3.rs-1976861/v2 

3. Payne AB, Ray LC, Cole MM et al. Reduced Risk for Mpox after Receipt of 1 or 2 Doses of JYNNEOS Vaccine Compared with Risk Among Unvaccinated Persons-43 U.S- Jurisdictions, July 31-October1, 2022. MMWR December 9, 2022/Vol. 71/No.49 

4. Pischel L, Martini BA, Yu N, et al. Vaccine effectiveness of 3rd generation mpox vaccines against mpox and disease severity: A systematic review and meta-analysis. Vaccine, 2024. Available from: https://doi.org/10.1016/j.vaccine.2024.06.021  

5. Payne AB, Ray LC, Kugeler KJ, et al. Incidence of Monkeypox Among Unvaccinated Persons Compared with Persons Receiving >/=1 JYNNEOS Vaccine Dose - 32 U.S. Jurisdictions, July 31-September 3, 2022. MMWR Morb Mortal Wkly Rep, 2022. 71(40): p. 1278-1282.  

6. UK Health Security Agency. Recommendations for the use of pre and post-exposure vaccination during a monkeypox incident. Available from: https://www.gov.uk/government/publications/ monkeypox-vaccination 

7. Greenberg, R.N. et al, A Multicenter, Open-Label, Controlled Phase II Study to Evaluate Safety and Immunogenicity of MVA Smallpox Vaccine (IMVAMUNE) in 18-40 Year Old Subjects with Diagnosed Atopic Dermatitis. PLOS ONE, 2015. 10 (10):p e0138348 

8. Dashraath, P. et al. Guidelines for pregnant individuals with monkeypox virus exposure. Lancet June 21, 2022. Available from: https://doi.org/10.1016/S0140-6736(22)01063-7