Federal health officials are warning that there could be a “resurgence” of mpox cases in the coming months following a steady nine-month nationwide decline.
“Spring and summer season in 2023 could lead to a resurgence of mpox as people gather for festivals and other events,” the Centers for Disease Control and Prevention said in an alert Monday for health care professionals.
Cases of the virus, formerly called monkeypox, have stayed low in the U.S. since they peaked last August — when 646 cases were reported in one day. There has been however, a recent cluster reported in the Chicago area, the CDC said.
Mpox cases have been declining since they peaked in August last year, the CDC said.
Over a recent 18-day period, the city’s health department saw 12 confirmed cases and one probable case of the virus. All of the cases from April 17 to May 5 were among symptomatic men — 69% of whom had received both doses of the two-dose Jynneos mpox vaccine.
The CDC said it does not know why such a high percentage of the people vaccinated became infected. It also doesn’t know whether immunity after vaccination has decreased among those individuals, or if the virus has mutated. The agency said it is conducting studies to help determine how long immunity post-vaccination lasts.
Though no vaccine is 100% effective in preventing infection, it does reduce the chances of getting and spreading the virus and could make the symptoms less severe, the CDC said.
Mpox spreads through close, personal contact, including skin-to-skin contact and during sex.
Dr. Jay Varma, director of the Center for Pandemic Prevention and Response at Weill Cornell Medicine, told CNN that though there’s a “very real risk” of a surge over the next few months it likely won’t be as large as last year.
“This is because many people at risk were either infected or vaccinated,” Varma said.
The vaccination rate is still rather low, however, with only 23% of the estimated population at risk for mpox being fully vaccinated, according to the CDC.
A dose of the mpox vaccine is seen prepared at a mobile vaccination clinic in California in 2022. The Jynneos vaccine consists of two doses administered 28 days apart.
Individuals recommended for the vaccine are those who face an increased risk of mpox exposure. This includes men who have sex with multiple male partners or with a male partner who has had multiple recent sexual partners.
Mpox is most commonly spread through close, sustained physical contact and, in the current global outbreak, it has almost exclusively been associated with sexual contact.
The symptoms include a rash on the hands, feet, chest, face or mouth, or near the genitals. This initially can look like pimples or blisters and may be painful or itchy. Those infected may also experience flu-like symptoms — including fever, chills, swollen lymph nodes and muscle aches.