US health authorities on Tuesday authorized a new procedure for injecting the monkeypox vaccine which should make it possible to vaccinate more people with the same amount of product, at a time when doses are lacking in the country. The United States Medicines Agency (FDA) has also authorized the administration of the vaccine in individuals under the age of 18 considered to be at high risk of infection. For those over 18, the vaccine will now be able to be administered differently: via an intradermal injection, between the upper layers of the skin, and no longer subcutaneous, deeper.
Goal of 2.2 million injections
This new strategy should make it possible to use less product per injection and therefore “to increase the total number of doses available up to five times”, the FDA said in a statement. Two injections four weeks apart will still be necessary. The agency said it was relying on data from a 2015 clinical trial that showed the immune response was similar in people given a subcutaneous injection, compared to those given a fifth of the dose so intradermal. So far, some 620,000 doses of the vaccine made by Bavarian Nordic (marketed as Jynneos in the US) have been distributed to various US states.
Some 440,000 additional doses still need to be distributed and could therefore allow up to 2.2 million injections under the new strategy. The government has also ordered an additional 5 million doses, which will start arriving from September and run through 2023, and therefore have the potential to supply 25 million doses. The decisions announced Tuesday were enabled by an emergency use authorization granted to the vaccine by the FDA — which itself follows the declaration of a public health emergency in the country last week over the outbreak.
For the authorization in minors, the FDA pointed out that it reviewed the safety data of this vaccine, as well as those of another vaccine given in children against smallpox. “We are very confident about the safety of this approach”, said at a press conference Peter Marks, of the FDA, justifying this decision by a recent increase in the number of children who have potentially been exposed to infected people. The United States currently has nearly 9,000 cases of monkeypox, including a fifth in New York State alone. The vast majority of cases involve men who have sex with men.
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