A smaller dose of the monkeypox vaccine appears to still be effective and can be used to stretch the current supply by five times, the European Medicines Agency said Friday, echoing a recommendation made earlier this month by the U.S. Food and Drug Administration.
The EU drug regulator said in a statement that injecting people with one-fifth of the regular dose of the smallpox vaccine made by Bavarian Nordic appeared to produce similar levels of antibodies against monkeypox as a full dose.
The approach calls for administering Bavarian Nordic's vaccine with an injection just under the skin rather than into deeper tissue, a practice that may stimulate a better immune response. People still need to get two doses, about four weeks apart.
The EMA said national authorities could decide, "as a temporary measure" to use smaller doses of the vaccine to protect vulnerable people during the ongoing monkeypox outbreak.
EU health commissioner Stella Kyriakides said the decision would allow the vaccination of five times as many people with the continent's current supply.
"This ensures greater access to vaccination for citizens at risk and health care workers," she said in a statement.
Earlier this month, the U.S. FDA authorized a similar plan to extend the country's monkeypox vaccine stocks. The technique has previously been used to stretch supplies of vaccines during other outbreaks, including yellow fever and polio.
The unusual recommendations from both regulators acknowledge the extremely limited global supplies of the Jynneos vaccine, originally developed against smallpox. Bavarian Nordic is the only company that makes it, and it expects to have about 16 million doses available this year. On Thursday, the U.S. also announced a new agreement with a Michigan manufacturer to help speed production of 5.5 million vaccine vials recently ordered by the government.
The EMA authorized the vaccine in July based on experimental data that suggested it would work; the World Health Organization has estimated the shot is about 85% effective at preventing monkeypox.
Globally, there are more than 40,000 cases of monkeypox, of which about half are in Europe. Earlier this week, WHO chief Tedros Adhanom Ghebreyesus said there has been a 20% increase in cases reported in the last two weeks and that nearly all infections have been reported in men who are gay, bisexual or have sex with other men.
Tedros said WHO was in talks with vaccine manufacturers and countries to see if any might be willing to share doses. Africa has reported the highest number of suspected monkeypox deaths and although the disease has been endemic in parts of central and west Africa for decades, it has only a small supply of vaccines being used as part of a research study.
About 98% of monkeypox cases beyond Africa have been reported in men who are gay, bisexual or have sex with other men. WHO said there is no sign of sustained transmission beyond men who have sex with men, although a small number of women and children have also been sickened by the disease.
Monkeypox spreads when people have close, physical contact with an infected person's lesions, their clothing or bed sheets. Most people recover without needing treatment, but the lesions can be extremely painful and more severe cases can result in complications including brain inflammation and death.
In the U.K., which at one point had the biggest outbreak outside Africa, officials said earlier this week they have seen signs the outbreak is slowing down.