NIAC Recommendations for Monkeypox Vaccination

These recommendations reflect a dynamic vaccination programme strategy. Scientific evidence about the use of vaccines in the 2022 monkeypox outbreak is emerging and being refined. Recommendations may be updated when more information becomes available.

• The epidemiology of monkeypox has been changing with an increase in detected cases, possibly contributed to by the cessation of smallpox vaccination with subsequent waning of immunity, and other factors including deforestation, disruption of animal habitats, increase in population mobility and possible genetic evolution of the virus.
• The 2022 outbreak involving many countries is under investigation. While the index case in the UK had a travel history, linkage to other cases is not clear although linked cases within the outbreak have been identified.
• The majority of cases have been mainly, but not exclusively, in those who have selfidentified as gay, bisexual or men who have sex with men (gbMSM).
• While most casesin this outbreak have been mild and self limited,severe disease and death can occur. The disease may be more severe in young children, pregnant women, older persons and those with severe immunocompromise, especially if related to HIV.
• Smallpox (vaccinia) vaccines are effective against monkeypox. Imvanex, an attenuated nonreplicating vaccinia virus is licensed in the US and Canada for prevention of smallpox and monkeypox, and in Europe by the EMA for prevention of smallpox.
• Imvanex has been used in Europe for pre and post exposure prophylaxis against monkeypox. The vaccine can prevent the onset of symptoms if given within four days of exposure. If given between 5-14 days after the date of exposure, it may reduce the symptoms but may not prevent the disease.
• Monkeypox in pregnancy can be associated with adverse outcomes including fetal death.
• Consideration may be given to using Imvanex, a non replicating vaccine, in pregnancy and during breastfeeding for those at increased risk following individual benefit risk assessment.
• As monkeypox may cause severe disease in children, Imvanex may be considered for use in children at increased risk following an individual risk assessment. Although the vaccine is not authorised for use in those aged under 18 years, adverse events are expected to be similar to those in adults based on clinical trials of vaccines using similar platforms.