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The UK Health Security Agency (UKHSA) have announced that monkeypox vaccines are to be piloted in smaller but equally effective doses to maximise supply.
Prof Paul Hunter, Professor in Medicine, UEA, said:
“Both the European Medicines Agency Emergency Task Force and USDA have authorised the use of the reduced dose as an intradermal (ID) injection. There is strong evidence from several different vaccines that intradermal infections can provide just as effective immunity with much lower dose, typically 10-20% of the intramuscular (IM) or subcutaneous (SC) doses. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4915566/.
“Intradermal injections are a bit more difficult to give than intramuscular or subcutaneous injections and take a bit more time to complete (or at least I found that to be the case when I was giving them). They also have a greater risk of local reactions pain and itchiness at the site of the injection.
“Nevertheless the benefit of the much reduced dose needed by ID injection at a time when vaccine supplies are challenged would make this common sense once this has been shown to be effective in Monkeypox, something that would not take long to complete.
“However, I am a little puzzled by the need to do this survey as the UK current guidelines already allows for a reduced dose intradermal injection in immune competent people “0.5 ml subcutaneous / intramuscular injection OR 0.1ml intradermal injection (during supply constraints)“ https://www.gov.uk/government/publications/smallpox-and-vaccinia-the-green-book-chapter-29 . So the reduced dose regimen by ID could be being given already.”
Dr Jake Dunning, Senior Researcher in Emerging and High Consequence Infectious Diseases, Pandemic Sciences Institute, University of Oxford, said:
“This is an important pilot because if it proves to be successful, then it could help optimise the use of finite vaccine stocks. It’s good to see UKHSA continuing to do all it can to improve vaccination strategies for those at risk of exposure to monkeypox virus.
“Ideally, we should not just rely on existing data on studies showing that intradermal administration of Imvanex vaccine – under controlled conditions – produces just as good antibody levels as giving the vaccine via intramuscular injection. Intradermal vaccination is not a common vaccination method in many countries, including the UK, so collecting real world data will be important to see if vaccines are administered appropriately and produce the desired effect – measurable antibodies in blood that translates into protection against infection. The first step may just be to see if healthcare practitioners can be trained rapidly to administer intradermal vaccine correctly and consistently.
“The existing research cited by UKHSA also reports increased rates of local side effects at the site of injection when the vaccine is given via the intradermal route; therefore, patients participating in these pilots will need to be made aware of the potential for short-term and longer-lasting skin reactions at the injection site, for both first and second doses, and data will need to be collected on these side effects and the tolerability of intradermal vaccine, and whether this impacts on uptake of Imvanex vaccine if it is offered as intradermal vaccine going forward.
“Overall, I am hopeful that real life experience from these pilots in the UK and from similar initiatives in other countries will show intradermal vaccination to be both safe and effective. A positive experience could mean we can immunise many more people more quickly, particularly in settings with more limited resources and in countries facing temporary or more persistent vaccine access issues.”
Declared interests
Dr Jake Dunning holds an honorary position at UKHSA, as a Honorary Consultant in Reference Virology. His views do not necessarily represent those of UKHSA or the Department of Health and Social Care and he is not speaking here on behalf of UKHSA, DHSC or the NHS.
He has previously received Imvanex vaccine via the intramuscular route in his role as a doctor who looks after patients hospitalised with monkeypox. He is a Chief Investigator for an existing and ongoing, unrelated, observational study (sponsored by UKHSA) looking at immunological responses and side effects in specialist healthcare workers who receive Imvanex vaccine during monkeypox outbreaks.
He is not employed by UKHSA or Bavarian Nordic, and he has no financial interests or investments in licensed or experimental orthopox vaccines or treatments. He has not received sponsorship or honoraria from Bavarian Nordic or any other pharmaceutical companies that develop and/or produce vaccines and treatments for monkeypox and other orthopox infections.
For all other experts, no reply to our request for DOIs was received.