The US Food and Drug Administration on Tuesday authorized a new way of administering the monkeypox vaccine. Health care providers may now give Jynneos through intradermal injection, which will increase the total number of doses available by up to five times.

Most vaccines we get these days go either into the muscle in our arm (intramuscular injection) or into the fatty tissue under our skin (subcutaneous injection), like Jynneos has been given so far. Vaccines given intradermally go into the outer layer of our skin. This approach requires a smaller dose of the vaccine for each shot, increasing the number of people able to be vaccinated per vial of Jynneos. 

This type of vaccination has also been called "dose-sparing" when vaccine supply is low and the intradermal method is also used in the test for tuberculosis, for example. The move from health officials comes after the US had faced many issues in getting adequate supply of Jynneos out to people who are most at risk of catching monkeypox. 

"In recent weeks the monkeypox virus has continued to spread at a rate that has made it clear our current vaccine supply will not meet the current demand," FDA Commissioner Robert M. Califf said in a press release. "By increasing the number of available doses, more individuals who want to be vaccinated against monkeypox will now have the opportunity to do so." 

The FDA's clearance followed a determination Tuesday from the US Department of Health and Human Services that while monkeypox remains a public health emergency, the FDA may make emergency use authorizations of vaccines to better respond to the outbreak.  

When it authorized the new vaccine method, the FDA referenced a study published in 2015 that found that a smallpox vaccine given intradermally gave a similar immune response in people compared to the vaccine given subcutaneously. Other benefits of intradermal vaccination, generally speaking, include cost savings, and the ability to give more people immunity.

But intradermal vaccination also presents some challenges, including a potentially trickier administration process for health care providers, who will need special training, and questions of how well immunocompromised people most at-risk of severe disease would respond to this method of vaccination. 

In its authorization of the new way of administering Jynneos, the FDA said two doses of the vaccine given four weeks apart are still required. This runs against moves made by cities like New York and San Francisco, which have been allowing appointments only for the first vaccine dose because supply has been so limited. 

There've been over 9,400 cases of monkeypox reported in the US as of Tuesday. Anyone with close contact to monkeypox can get it, but men who have sex with men are currently being most affected in the outbreak so far. Some men as well as other people with possible exposure to monkeypox are eligible for a monkeypox vaccine, even after an exposure.

Read more: What to Know About Monkeypox  

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.