Amid a recently announced national public emergency and vaccine shortages, the Food and Drug Administration announced it is reviewing a new vaccine approach that could lead to a fivefold increase in the supply of the Jynneos monkeypox vaccine in the US.
“Please know that we have explored all scientifically viable options, and we believe this could be a promising approach,” said FDA Commissioner Dr. Robert Califf at a press conference on Thursday.
The vaccine would be delivered in a smaller, shallower injection under the skin, a method Califf said would still be safe and effective and would allow up to five doses to be drawn from one vial.
The new strategy has yet to be tested in clinical trials — a process that could take weeks or months. But experts say previous studies look promising, and if successful, could be a safe way to stretch the limited vaccine supply.
“This kind of research is exactly what FDA and NIH should be leading in this moment of public health emergency,” said Dr. Josh Sharfstein, a former FDA commissioner and currently vice dean for public health practices and community engagement and director of the Bloomberg American Health Initiative at the Johns Hopkins Bloomberg School of Public Health.
“If much less vaccine can be used with intradermal injection, as opposed to intramuscular injection, then the current stock of monkeypox vaccines could be expanded to accommodate many more people.”
The Jynneos monkeypox vaccine is currently FDA-approved as a subcutaneous injection given in two doses four weeks apart. The new strategy would still be a two-dose injection, according to the CDC.
Stretching supplies could help “close the gap,” Califf said. The White House has already made 1.1 million doses available to states and expects 6.9 million doses by May 2023, according to the HHS.
Here’s what you need to know about the new process:
What is an intradermal injection?
The dermis is the second layer of the skin, below the epidermis, the visible layer of the skin. Most routine vaccinations are given as intramuscular or subcutaneous injections that go deeper than the dermal layer.
But an intradermally administered vaccine would create a small air bubble under the skin. This is the exact same technique already used in tuberculin skin testing, also known as a PPD test.
How will the FDA know if this is working?
This smaller dose should be tested like any other vaccine to make sure it is both safe and effective.
“It is important to note that the overall safety and efficacy profile will not be sacrificed for this approach,” Califf said.
But this is not the same as starting from scratch with a vaccine and other vaccines have been shown to work with this method. It was used all over the world in the 1970s against smallpox.
“Smallpox vaccine used worldwide to eradicate smallpox from the planet required intradermal vaccination,” Dr. Richard Kuhn, Krenicki Family Director of Inflammation, Immunology and Infectious Disease at Purdue University and editor of Virology at ABC News.
dr. Dan Barouch, William Bosworth Castle Professor of Medicine, Harvard Medical School, Ragon Institute of MGH, MIT, and Harvard and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, says the intradermal method is “very effective “because there are many immune cells just under the skin, and often lower doses are needed than with intramuscular vaccination.”
More recently, the flu vaccine against the H1N1 strain that caused a pandemic in 2009 has been tested intradermally in many research studies and found to be equally effective at one-fifth the dose of the intramuscular injection.
How will the shots get into the guns?
If the Jynneos vaccine against monkeypox passes a clinical trial, there is one more barrier to overcome. Barouch also warns that administering a vaccine in this way can pose a technical challenge, saying, “most people are not trained or experienced in administering vaccines by the intradermal route.”
But experts say it’s a skill that can be learned easily.
“Anyone who can be an expert in intramuscular administration, but you would still want to give them the training for the intradermal. As I said, they could be learned very quickly and they could be up and running in a very short time,” explains Dr. Robert Frenck, director of the Vaccine Research Center at the Cincinnati Children’s Hospital Medical Center, told ABC News.
Frenck also says this national public health emergency is a reminder that living in a globalized world means an outbreak anywhere is a danger to people everywhere.
“That’s why the vaccines are so important. That keeps us healthy,” said Frenck.
dr. Pediatric eligibility eligibility Jade A Cobern is a member of the ABC News Medical Unit and a general preventive medicine resident at Johns Hopkins.
Cheyenne Haslett contributed to this report.