U.S. Moves to Stretch Out Monkeypox Vaccine Supply

WASHINGTON — The Biden administration has decided to stretch out its limited supply of monkeypox vaccine by allowing a different method of injection that uses one-fifth as much per shot, according to people familiar with the discussions.

In order for the Food and Drug Administration to authorize so-called intradermal injection, which would involve injecting one-fifth of the current dose into the skin instead of a full dose into underlying fat, the Department of Health and Human Services will need to issue a new emergency declaration allowing regulators to invoke the F.D.A.’s emergency use powers. That declaration is expected as early as Tuesday afternoon.

The move would help alleviate a shortage of vaccine that has turned into a growing political and public health problem for the administration.

In less than three months, more than 8,900 monkeypox cases have been reported. The virus spreads from person to person primarily through close physical contact with infectious lesions.

Even though it invested more than $1 billion in developing the two-dose vaccine known as Jynneos that works against both monkeypox and smallpox, the government has only 1.1 million shots on hand. It needs about three times as many doses to cover the 1.6 million to 1.7 million Americans who, according to the Centers for Disease Control and Prevention, are at high risk of contracting monkeypox.

The vaccine is currently delivered in two 0.5-milliliter doses 28 days apart, with immune protection reaching its “maximum” 14 days after the second dose, according to the C.D.C.

The shot is recommended by the C.D.C. for people who have been exposed to monkeypox and those who might be likely to get it. Those in the latter category include people identified as a contact of someone with monkeypox, those who know a sexual partner from the last 14 days was diagnosed with the disease and those who have had “multiple” sexual partners in that time frame in an area with “known monkeypox.”

Federal health officials said last week that so far, they have distributed about 600,000 doses of the vaccine to state and local jurisdictions.

The Department of Health and Human Services last week also issued a broader public emergency declaration that allowed the federal government to more easily allot money and other resources to fight the virus.

Research on intradermal injection of the monkeypox vaccine is essentially limited to one study. It showed that when the vaccine was injected between skin layers, it induced an immune response comparable to that from a standard injection into the fat underneath the skin. Federal officials have consulted with a variety of outside groups about switching to the intradermal injection approach, including the Infectious Diseases Society of America, according to people…