Federal health authorities are urging at-risk Americans to continue taking precautions against early data suggests that the Jynneos vaccine for the virus may be helping to slow cases., while
The figures, published Wednesday on the CDC's website, tally reported monkeypox infections in people eligible for the vaccine in 32 states. Through late August, rates of infections were 14 times higher in people who had not gotten at least one shot.
The new findings come as the Biden administration is touting new moves to expand eligibility for the shots, and other initiatives aiming to drive down severe infections and deaths.
"These new data provide us with a level of cautious optimism that the vaccine is working as intended. These early findings, and similar results from studies in other countries, suggest that even one dose of the monkeypox vaccine offers at least some initial protection against infection," CDC Director Dr. Rochelle Walensky said at a briefing.
However, the CDC says its new "crude case rates" data carry several major limitations that make it difficult to determine the precise impact the vaccine is having on reducing.
For example, people who are vaccinated may already be less likely to participate in activities that raise their risk of catching the virus, which is largely spreading through intimate contact among men who have sex with men.
Not every state is reporting enough data to feed into the estimate. New York, which makes up more than 15% of the nation's 25,509 confirmed cases, is not yet included in the rates.
The agency is still waiting for more data after people get second doses of the shot. Laboratory data suggests the follow-up shot will provide more "durable, lasting protection" against monkeypox, Walensky said.
The National Institutes of Health is also still gathering data from its clinical trial scrutinizing the "intradermal" approach to administering the shots, which is being used in the U.S. to stretch supply of the vaccine. That study is not expected to yield its first results until early 2023.
For now, Walensky urged vaccinated people to continue to take steps to "further protect themselves from infection."
"Consider reducing the behaviors that could increase risk of exposure. These prevention measures are key to continuing to drive down monkeypox infections," said Walensky.
The promising data on the shots comes as the Biden administration is now moving to ease barriers it says may have deterred some from getting the monkeypox vaccine.
Last week, the CDC said it had now recorded more than half a million first doses of vaccine administered nationwide. That works out to around a third of the number of people the White House estimates are "most at risk of contracting the virus."
Citing a, federal health officials said they are now moving to a "pre-exposure prophylaxis" or PrEP approach to vaccine eligibility — meaning offering it to people as a preventive measure before they had any known exposure.
Previously, the CDC had only recommended the shots for "post-exposure prophylaxis" in people who were likely to have already been exposed to the virus.
Federal guidelines now say health departments should now offer it to broader swaths of Americans before they are exposed to the virus, including all gay men who have been diagnosed with a sexually transmitted disease in the last six months.
"That increases who is eligible for vaccination and encourages vaccine providers to minimize the risk assessments of people seeking vaccine. Fear of disclosing sexuality and gender identity must not be a barrier," said Dr. Demetre Daskalakis, the White House's deputy response coordinator for monkeypox.
The CDC also updated its guidance to allow the shots to be administered in other parts of the body, like in the upper back or shoulder.
"Many jurisdictions and advocates have told us that some people decline vaccine to monkeypox because of the stigma associated with the visible, but temporary mark, often left on their forearm," said Daskalakis.
While most monkeypox infections resolve after weeks of often very painful rashes and lesions, a handful of patients have ended up in the hospital and at least has been officially blamed on the virus.
Health officials have voiced concern over growing reports of severe infections, even as cases have been slowing overall. Walensky said Wednesday that she was not aware of any of these kinds of severe infections happening in people who had been vaccinated with Jynneos.
An updated "technical report" from the agency is also expected by early next month, outlining trends in where and how the virus is still spreading.
"We want to bring attention to the fact that in recent weeks we've been hearing about some severe infections," the CDC's Dr. Agam Rao said at a webinar hosted by the Infectious Diseases Society of America over the weekend.
The agency has been working on updated recommendations for doctors treating these severe cases, which federal data suggests are now happening mostly in immunocompromised Hispanic or Black men with advanced HIV.
"Even though we're finding it, I guess, comforting or reassuring that the number of case counts are decreasing, we just want to highlight that there are some severe infections occurring," Rao said.