The Biden administration, amid criticism it was slow to act on the monkeypox outbreak and still not meeting the demand for vaccines as the number of cases continues to grow, has announced a shift in guidance for implementation of the shot in an effort to enhance availability.

As the estimated number of monkeypox cases in the United States reaches 8,900, top health officials announced the new move on Tuesday as part of a decision by Secretary of Health & Human Services Xavier Becerra to issue a determination under Section 564 of the Federal Food, Drug and Cosmetic Act to justify emergency use authorization of vaccines. The announcement follows up on the Biden administration’s announcement last week declaring the monkeypox outbreak a public health emergency.

Becerra said in a conference call with reporters the 564 determination and change in approach to vaccines would “boost and strengthen” the Biden administration’s response to monkeypox, which has overwhelmingly affected gay and bisexual men, and “safely accelerates and multiplies our supply of effective vaccines by up to fivefold.”

“Today’s action also reaffirms HHS and this administration’s commitment to using all available resources and capabilities to end the monkeypox outbreak and provide the best possible care to those suffering from the virus,” Becerra added.

The new vaccine approach, which may may be considered minor to non-medical observers, would change injections of the JYNNEOS vaccine from the subcutaneous route (delivery of the vaccine under the fat layer underneath the skin) to the intradermal route (delivery of the vaccine into the layer of skin just underneath the top layer). In theory, that would allow for greater accessibility of monkeypox vaccines as it increases the number of doses from each vial of vaccine.

The change was made amid criticism the Biden administration failed to meet the demand for vaccines during the outbreak and geographic inequity as certain metropolitan areas of the country have more access to vaccines than other places.

As The New York Times reported last week, the Biden administration has faced criticism for not moving quickly enough in acquiring and distributing vaccines, including bulk stocks already owned by the U.S. government manufactured in Denmark by Bavaria Nordic now being given to other clients.

“The government is now distributing about 1.1 million doses, less than a third of the 3.5 million that health officials now estimate are needed to fight the outbreak,” the Times reported. “It does not expect the next delivery, of half a million doses, until October. Most of the other 5.5 million doses the United States has ordered are not scheduled to be delivered until next year, according to the federal health agency.”

Biden officials, nonetheless, touted the numbers of vaccines and tests in response to monkeypox as a positive, acknowledging the 1.1 million vaccines being made available as well as delivery of more than 620,000 of those doses, deployment more than 15,000 courses of the monkeypox treatment and increasing the country’s capacity to administer tests on a weekly basis to around 80,000. Meanwhile, officials also promoted the change in approach in vaccines as means to allow greater accessibility to the shots.

Rochelle Walensky, director of the Centers for Disease Control & Prevention, promoted during the conference call the use of intradermal injections and said they’re “often used for TB skin tests and have been used for other types of vaccines.”

Although Walensky conceded some health care providers “may not be as familiar with intradermal administration” as they are with subcutaneous injection, she said CDC would make additional guidance materials available, including a clinician alert message to the Association of State & Territorial Health Officials, outreach to key clinician partners and an education resource video. The change in guidance, Walensky said, is for vaccine implementation in adults, but children — where single digit monkeypox cases have been reported — would continue to receive vaccination in the traditional subcutaneous approach.

But health experts aren’t responding with overwhelming praise to the decision to change the guidance on vaccine implementation from subcutaneous injections to intradermal injections, expressing concerns the new approach may be insufficient.

Jennifer Kates, director of global health & HIV policy at the Kaiser Family Foundation, was among those saying the change in guidance on vaccine approach was a mixed bag and told the Blade more data is needed to evaluate the effectiveness.

“As we saw with COVID, using these authorities in the context of public health emergencies is an important strategy,” Kates said. “In this case, this step will significantly expand access to vaccines for those most at risk. However, there remain questions about the effectiveness of this approach — real world studies are needed — and challenges to translating vaccines into vaccinations.”

Peter Marks, director of the Center for Biologics Evaluation & Research (CBER) at the Food & Drug Administration, was asked during the conference call with reporters to respond to concerns the change in guidance was insufficient and downplayed the novelty of implementing the vaccines through the intradermal route as “not at all new.”

“In fact, the reason why the Bavaria part of this equation comes from the fact that in Germany, this vaccine was given intradermally originally, in an effort to replicate the original version of the smallpox vaccine,” Marks said. “It’s been given to thousands of people intradermally, so this isn’t the first time it’s been done.”

Walkensky said the intradermal vaccine approach has been implemented amid policies among localities to implement a one-dose approach to the JYNNEOS vaccine through the subcutaneous route. (The D.C. government is one of the jurisdictions that had enacted a one-dose approach amid a vaccine shortage.) There is not data, Walkensky said, to support that approach and “in fact, if anything, there are data saying that that is not protective enough.”

“So by using this alternative strategy of intradermal dosing, not only do we have more doses, but we actually allow people to get two doses in a way that shows immunologic response that’s superimposable from the subcutaneous dosing,” Walkensky said. “So we have more doses, and in fact, we have the ability to doubly vaccinate people so that they get the protection that they need.”