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Do I need an mpox (monkeypox) vaccine and is it safe?

Mpox (monkeypox) has been declared a communicable disease incident of national significance in Australia. The federal government has secured 450,000 doses of the third generation JYNNEOS mpox vaccine, with the delivery of 22,000 doses imminent.

With nearly 70 cases of mpox now reported across Australia, and states and territories edging closer to launching vaccination programs, we take a closer look at the safety of mpox vaccines and who should receive the vaccine. 

What is mpox and how does it spread?

Mpox is caused by infection with the mpox virus, which is in the same family as the smallpox virus. While generally not as severe as smallpox, mpox can cause serious disease in immunocompromised people, children and pregnant women.
Mpox mainly spreads from one person to another by direct skin-to-skin contact. Less commonly, it may be spread by breathing in droplets breathed out by a person with mpox during prolonged close contact, or contact with infected bodily fluids or contaminated objects, such as bedding or clothes.

Mpox infection can cause fever, headache, muscle aches, swollen lymph nodes, a painful rash and scarring. 

Antivirals can help treat mpox, but vaccination in those most at risk remains the best protection against the virus. 

Although mpox has been observed internationally for some time, this is the first time it has been seen or transmitted in Australia. 

Which mpox vaccines are available in Australia?

There are currently two vaccines available in Australia that can prevent mpox – JYNNEOS and ACAM2000. The Australian Advisory Group on Immunisation (ATAGI) recommends JYNNEOS to be the preferred vaccine for vaccination in individuals both before exposure to the mpox virus (pre-exposure prophylaxis – PrEP) and after exposure to the mpox virus (post-exposure prophylaxis - PEP). This is due to its more favourable safety profile and comparative ease of administration. 

JYNNEOS is made using a weakened vaccinia virus that can no longer replicate and so it cannot cause disease. Two doses of the vaccine are needed, with at least 28 days between each dose. If there is a delay in giving the second dose, there is no need to restart the vaccine course. Instead, the second dose should be given as soon as available.

Who should get vaccinated?

Unlike COVID-19 vaccination, mpox vaccination is not recommended at a population-wide level. ATAGI recommends people at the highest risk of getting mpox should consider vaccination, including:

  • people who have been in contact with someone with mpox in the last 14 days 
  • people living with HIV 
  • people with recent history of multiple sexual partners, participating in group sex or attending sex on premises venues 
  • sex workers 
  • people in the groups above who plan to travel to a country with a significant outbreak
  • immunisation providers who are administering the ACAM2000 smallpox vaccine.

If you are unsure whether you should get a mpox vaccine, consult your general practitioner.

How does the mpox vaccine work?

JYNNEOS vaccine can lower the risk of catching mpox or severe outcomes from the disease. The vaccine course consists of 2 doses, at least 28 days apart. Maximum protection is seen two weeks after the second dose.
The vaccine can also be given to reduce the risk of infection, or the risk of serious illness, if someone has already been exposed to the virus through being a close contact. This is called post-exposure prophylaxis (PEP) and may be given as a one-off dose.
People who get vaccinated should continue to protect themselves from infection by avoiding close or intimate contact with someone who has, or may have, mpox.

What are the likely side effects from mpox vaccines?

Like most medicines used in healthcare, vaccines can have side effects, also known as adverse events following immunisation (AEFIs). These side effects are usually mild and temporary. Common side effects following vaccination with JYNNEOS vaccine include minor redness, pain or swelling at the vaccine site and sometimes systemic effects like tiredness, headache, muscle pain or fever

While ACAM2000 vaccine has been associated with heart problems such as myocarditis, this has not been observed in JYNNEOS clinical trials. If you’re allergic to any of the vaccine components, including gentamicin, ciprofloxacin or chicken egg protein, it is recommended you discuss vaccination with your doctor first.

If you experience an AEFI following monkepox vaccination, you should seek medical advice from your treating doctor and report the AEFI on the Therapeutic Goods Administration (TGA) website.

What is being done to monitor the safety of mpox vaccines in Australia?

Australia has one of the most robust vaccine safety monitoring systems in the world. The TGA will be monitoring any reports of serious AEFIs following mpox vaccination via its passive reporting system.

Also, AusVaxSafety will be actively monitoring the adverse event profile and safety of the mpox vaccine to ensure the vaccine is performing as safely as expected in real-world conditions. Individuals can take part in active surveillance by scanning the AusVaxSafety QR code at time of vaccination at participating clinics. Participants will receive a short follow-up survey to monitor side effects in the weeks following vaccination. Find out more about AusVaxSafety mpox vaccine safety surveillance here.