Independent vaccine advisers at the U.S. Centers for Disease Control and Prevention voted unanimously on Wednesday in favor of the two-dose Jynneos mpox vaccine for adults at risk of contracting the disease during an outbreak.
If the CDC agrees with the committee’s recommendation, there will be a recommendation in place to give the vaccine to people at risk for mpox in future outbreaks.
The number of new cases of mpox, formerly known as monkeypox, has declined significantly in the United States since the peak of the last outbreak in August. The current seven-day average shows there are still two new cases a day, down from around 450 cases a day in August – but two cases is more than the US has had in previous years, has said the experts.
“We have a very effective vaccine,” said committee member Dr. Jamie Loehr, owner of Cayuga Family Medicine in Ithaca, New York. “We have good data.
“And there is actually quite a high death rate if I do my math correctly. It’s about 1 in 1,000, and it’s not an insignificant death rate. So I am very supportive of that,” Loehr added.
All 18 members voted in favor of the vaccine recommendation: “ACIP recommends the Jynneos 2-dose series of vaccines for persons 18 years of age and older at risk of mpox during an outbreak of mpox.”
In 2021, the committee voted in favor of the Jynneos vaccine for people at occupational risk of exposure to the virus. In August, at the height of the outbreak, the vaccine was granted emergency use authorization to help prevent new diseases.
More than 1.18 million Jynneos vaccines have been administered in the United States, according to the CDC.
Although the vaccine’s effectiveness has never been demonstrated in clinical trials for mpox, studies conducted during the outbreak have shown it to be up to 83% effective, the CDC said. Still, more data is needed to fully understand how well it works in people with underlying health conditions that leave them with weakened immune systems.
The incidence of Mpox in unvaccinated people was 7.4 times higher than in those who received one dose of Jynneos vaccine and 9.6 times higher than in those who received two doses of Jynneos vaccine, according to a presentation from the CDC.
There were no new or unexpected safety issues with the vaccine, according to the CDC presentation. Serious adverse events in adults were rare. There was no evidence that the vaccine increased the risk of myocarditis or pericarditis. The most common complaints were redness at the injection site and fatigue.
Even though mpox cases continue to decline, the CDC encourages those at risk to get vaccinated.
“We don’t think this outbreak is over, and that’s very important to keep in mind,” said Dr. Agam Rao, a physician with the CDC’s Division of Pathogens and High-Consequence Pathologies.
There is also a possibility of future outbreaks, she said.
“There has actually been a re-emergence of human cases after decades of no reported cases in some countries,” Rao added.
The United States led the world in mpox cases during the last outbreak, with more than 30,000 illnesses and cases in all 50 states. Those most at risk were members of the gay and bisexual community and other men who have sex with men, who accounted for 95% of cases. Overall, cases have been reported primarily among blacks, Hispanics and whites, with nearly a third of cases in each group.
Mpox also seemed to be spread mainly by sexually active people. Of the cases in which the CDC had sexual history information, 75% reported having had sex or close contact with another person three weeks before symptoms began, and 25% reported no contact. sex, according to the CDC.
Mpox is not a minor infection. The pain was “particularly pronounced” with the lesions, Rao said. Eye damage can lead to blindness. There may also be neurological complications and brain swelling. The most severe manifestations of mpox, including uncontrolled viral spread, have occurred in people with severely weakened immune systems.
The disease was rarely fatal, but there were 32 deaths, representing 0.1% of mpox cases, mostly in severely immunocompromised people.
The CDC said the committee will meet again in June to consider recommending the vaccine to people under 18. In October, the committee will consider a longer-term vaccine strategy.
“The recent outbreak has re-emphasized the risks infectious diseases can pose to our communities, the importance of a robust state and local public health response, the value of partners and communities engaged in responding to public health threats and the impact a vaccine can have in helping bring an outbreak under control,” said CDC Associate Director for Vaccine Policy Dr. Melinda Wharton.