Doses of the Jynneos vaccine are being released in the United States to prevent monkeypox amid rising cases in the past few weeks in several countries not endemic for the virus, according to the Centers for Disease Control and Prevention (CDC).
There are more than 1,000 doses of the Jynneos vaccine that were approved in the United States in 2019 and are in the strategic national stockpile, Jennifer McQuiston, deputy director of the Division of High Consequence Pathogens and Pathology at the CDC, told reporters at a media briefing on Monday.
The strategic national stockpile stores pharmaceuticals and medical supplies in case of an emergency that causes local supplies to be depleted. McQuiston said the United States has stock of the vaccine because it was preparing for a potential smallpox outbreak. She added that Jynneos vaccine doses are expected to ramp up very quickly in the coming weeks.
The Jynneos vaccine is approved in the United States to be used against smallpox and monkeypox in people aged 18 and over, determined to be at high risk of infection.
It is made by Denmark-based biotech group Bavarian Nordic, which recently announced that the Biden administration has placed an order for millions of doses, which would be manufactured and invoiced in 2023 and 2024.
“Right now we are hoping to maximize vaccine distribution to those that we know would benefit from it,” McQuiston said. “So those are people who’ve had contact with known monkeypox patients, health care workers, very close personal contacts, and those in particular who might be at high risk for severe disease.”
She added: “I can report that there has been a request for release of the Jynneos vaccine from the national stockpile for some of the high-risk contacts of some of the early patients. So that is actively happening right now.”
There are also more than 100 million doses of an older generation smallpox vaccine, ACAM2000, which has some potentially significant side effects, McQuiston told reporters. ACAM2000 was previously produced by Sanofi and is now made by Emergent BioSolutions.
It comes as public health officials are tracking more than 200 people for monkeypox, all of whom are contacts related to the first case that was confirmed in Massachusetts, with the vast majority being health care workers, McQuiston said.
The United States has one confirmed case of monkeypox in Massachusetts, and four cases that are presumed—one in New York City, one in Florida, and two in Utah—and are undergoing confirmation testing.
The World Health Organization (WHO) on Monday said there are about 200 cases that have been reported from several countries outside of Central and West Africa, where the disease typically occurs. No monkeypox deaths have been reported to date.
Monkeypox is a virus that has similar symptoms to smallpox in humans, but is normally less severe. It can cause symptoms including fever, muscle aches, fatigue, as well as a distinctive bumpy rash that can last up to a month. The rash often starts on the face and spreads to other parts of the body. Monkeypox also causes lymph nodes to swell while smallpox does not.
The disease typically self-resolves within two weeks to a month, but in rare cases, people can experience severe illness and die. There is “no proven, safe treatment for monkeypox virus infection,” the CDC states on its website. “For purposes of controlling a monkeypox outbreak in the United States, smallpox vaccine, antivirals, and vaccinia immune globulin (VIG) can be used.”
Two distinct clades, or families of monkeypox, have been identified, according to the WHO. They are the West African clade and the Congo Basin clade, also known as the Central African clade. The former has a 1 percent case fatality ratio, while the latter has up to 10 percent fatality. The WHO said that 3–6 percent of cases have resulted in deaths in recent times.
The WHO said on Monday it expects to confirm more monkeypox cases as it expands surveillance. It previously said the outbreaks so far are “atypical, as they are occurring in non-endemic countries.”
Rosamund Lewis, head of the smallpox secretariat that is part of the WHO Emergencies Program, told a streaming event on social media on Monday that the agency doesn’t have evidence that the monkeypox virus has mutated and that it has tended not to change. Lewis added that genome sequencing of cases will help inform understanding of the current outbreak.
Many but not all of the people who have been diagnosed in the current outbreak have been homosexual men, some officials have said.
The virus itself is not a sexually transmitted infection, but WHO officials said the recent surge in cases is linked to homosexual men. But they also said that anyone can contract monkeypox.
The WHO is asking dermatology and primary health care clinics, as well as sexual health clinics, to be alert to potential cases.
Reuters contributed to this report.