What Is Tecovirimat? Ed Markey Wants Monkeypox Treatment Stockpile Released

A U.S. senator has called on federal health agencies to expand access to the national stockpile of a limited smallpox treatment known as tecovirimat amid continued soaring demand for the Jynneos vaccine.

As of July 26, there were more than 3,500 cases of monkeypox in the U.S., according to Centers for Disease Control and Prevention (CDC) data, with only four states not declaring a single case yet.

The Department of Health and Human Services had distributed just over 310,000 doses of the Jynneos monkeypox/smallpox vaccine as of July 22 to various states and jurisdictions around the country in an effort to get priority groups protected.

Edward Markey and bottle of tecovirimat
Democrat Senator Edward Markey (L) seen at a Senate hearing in Washington, D.C. in March, 2021, and a container of tecovirimat (R) held by a former monkeypox patient in New York on July 19, 2022. Markey has called for expanded access to tecovirimat. Pool/AFP/Getty/Greg Nash/Yuki Iwamura

However, there has been news of demand outpacing supply in some locations, with appointments running out frequently in New York City and reports of people in Washington heading out of state in order to get a shot.

The Jynneos vaccine is not the only medication that can be used against monkeypox-like disease. Tecovirimat is a medicine that has been shown in animal studies to decrease the chance of death from infections with orthopoxviruses—of which monkeypox is a type—when given early on in the course of the disease, per the CDC.

In addition, case studies of monkeypox patients that included one person treated with tecovirimat have suggested the medicine might shorten the duration of illness.

The U.S. has more than 1.7 million courses of tecovirimat in its national stockpile. While efforts have been made to expand access to it, Massachusetts Democratic Senator Edward Markey has said such efforts have not gone far enough.

"Given the limited supply of vaccine and growing Monkeypox cases, the United States must use additional tools to respond to the outbreak, including expanding access to tecovirimat, to support patients suffering from this disease," Markey wrote in a letter to the CDC, Food and Drug Administration (FDA), and the Department of Health and Human Services (HHS).

Markey wrote that while the CDC has made tecovirimat available for the treatment of monkeypox, "CDC and FDA require health care providers to follow an extensive expanded access protocol each time the drug is prescribed. This protocol may discourage providers from seeking tecovirimat even in instances when it may benefit monkeypox patients under their care."

Tecovirimat is approved by the FDA for the treatment of smallpox in adults and children but not for the treatment of other orthopoxvirus infections like monkeypox. If a healthcare provider wants to use it for monkeypox, it has to go through an expanded access protocol.

According to the CDC, adverse reactions to the medicine include headache (12 percent); nausea (5 percent); abdominal pain (2 percent); and vomiting (2 percent) when given orally. When injected, most adverse reactions related to the injection site, such as pain (73 percent) and swelling (39 percent).

Tecovirimat has not been studied in pregnant and nursing women, though these groups are not excluded from treatment as long as they are given a careful clinical assessment and there is a discussion of risks, the CDC states. There have also been no clinical studies in child populations, though tecovirimat has been used in a 28-month-old child before with no adverse effects.

More information on tecovirimat can be found on the CDC's website here.