The Centers for Disease Control and Prevention alerted doctors across the country Monday about the potential risk of new mpox, formerly known as monkeypox, cases, warning that summer gatherings could lead to a "resurgence."
Public health experts interviewed by ABC News warned that the LGBTQ community -- which was disproportionately affected during the 2022 outbreak -- should be aware of signs and symptoms ahead of Pride Month celebrations in June.
Mpox cases have plummeted since a peak in the summer of 2022, with the World Health Organization calling an end to the emergency phase of the outbreak Thursday -- but the virus is not completely eradicated.
"While the transmission of monkeypox has reached its lowest levels since its emergence last year, the upcoming summer months, characterized by larger gatherings, present an increased risk of local outbreaks," John Brownstein, PhD, chief innovation officer at Boston Children's Hospital and an ABC News Contributor, said.
"The most important message is that mpox has not gone away," Dr. Richard Silvera (MD, MPH, CPH) Associate Program Director of the Infectious Disease Fellowship and Assistant Professor of Medicine (Infectious Diseases) at the Icahn School of Medicine at Mount Sinai, told ABC News.
Mpox infection is not usually life-threatening. It often appears as a painful rash, and some people experience flu-like symptoms.
The new CDC warning comes on the heels of a cluster of cases in Chicago, where health officials say there have been 12 confirmed cases and one probable case from April 17 to May 5.
A spokesperson for the Chicago Department of Public Health (CDPH) tells ABC News they are in close contact with the people who tested positive and are working with other health departments and the CDC in an ongoing investigation.
Meanwhile, health officials in cities like Chicago and San Francisco, as well as New York state, are amplifying their vaccination efforts for mpox as we approach the summer months and upcoming Pride events.
"We have been working with community partners to spread awareness of this resurgence and opportunities for vaccination, ahead of [International Mr. Leather], Pride, associated and other events," a CDPH spokesperson said.
None of the Chicago mpox patients have been hospitalized, but nine cases were among men who had been fully vaccinated.
Experts caution that many vaccines, including mpox, reduce the likelihood of infection but do not completely eliminate risk. Vaccination is still encouraged because people who are fully vaccinated can expect less severe symptoms.
Chicago health officials are not recommending booster doses for fully vaccinated people at this time. Both unvaccinated and vaccinated people should avoid close, skin-to-skin contact with someone who has mpox, according to the CDC.
"It's important to remember that vaccines—while incredibly helpful—are not our only way to reduce the risk of contracting Mpox," Silvera said. Other risk reduction strategies include "things like avoiding social and sexual contact if you have new skin lesions and asking your intimate contacts if they are experiencing symptoms or new skin changes," Silvera said.
The 2022 global mpox outbreak disproportionately impacted gay and bisexual men, but anyone can get or spread monkeypox, regardless of their sexual orientation or how they identify. It spreads most easily through close skin-to-skin contact, often during sex. It does not easily spread via casual contact, such as touching shared surfaces, like elevator buttons, or brushing against someone.
The CDC said that in the U.S., only one-quarter of eligible people are vaccinated, and urged vaccination among those who are high-risk.
The CDC recommends mpox vaccination for people with a known exposure, including close physical contact or sexual contact with someone who had an mpox rash. In addition, the CDC also recommends vaccination for people with HIV who have a higher risk of exposure, for gay, bisexual and MSM who have recently had more than one sexual partner or a recent sexually transmitted infection. Vaccination is also recommend for sex workers, and anyone who has recently visited a sex club or bathhouse.
"Vaccination stands as the most effective means of safeguarding oneself against monkeypox. However, only a small fraction of those eligible have received the vaccine thus far. Increasing vaccination coverage is likely to contribute to reducing monkeypox transmission," Brownstein said.
"The good news is that we have many tools to help prevent mpox including vaccination, as well as strategies to reduce your risk as you socialize this summer," Silvera said. Along with vaccination, Silvera said, "our best tool is communication: telling those you have intimate contact with if you are experiencing potential Mpox symptoms; asking if they are experiencing symptoms; and listening for updates from public health organizations as we learn more."