Mpox Virus Could Make A Comeback, CDC Warns: See NY Case Data

NEW YORK — An illness known as mpox, formerly monkeypox, could make a resurgence in New York this spring and summer with the beginning of festivals and vacations, the Centers for Disease Control and Prevention said in a health alert issued as public health officials investigate a cluster of cases in the Chicago area.

Since the mpox outbreak started last year through May 10, there have been 4,250 mpox cases reported in New York, according to CDC data.

Nationally, 30,395 reports of mpox illnesses, 42 of which have been fatal, have been reported since last spring. Every U.S. state has had at least three confirmed cases of mpox in the past year, and states with large populations have had several thousand confirmed cases, according to the data.

The 2022 outbreak subsided in August, but in the new alert, issued Monday, the CDC said spring and summer “could lead to a resurgence of mpox as people gather for festivals and other events.”

In the Chicago area from April 17 to May 5, 12 confirmed and one probable case of mpox were reported to the city’s Department of Public Health. All cases were among asymptomatic men. Four of the people had recently traveled to New York City, New Orleans and Mexico.

None of the patients were hospitalized, and nine patients had previously received the two recommended doses of JYNNEOS vaccine.

The CDC said that although vaccine-induced immunity is not complete, vaccination continues to be one of the most important prevention measures.

The agency expects new cases among previously vaccinated people to occur, but people who have completed their vaccine regimen may experience less severe symptoms than those who have not, according to the CDC.

Approximately 1.2 million JYNNEOS mpox vaccine doses have been administered in the United States since the beginning of the outbreak, but only 23 percent of the estimated population at risk for mpox has been fully vaccinated.

On Thursday, the New York State Department of Health announced that it published a groundbreaking study on the effectiveness of the JYNNEOS vaccine against mpox.

The study — Effectiveness of JYNNEOS Vaccine Against Diagnosed Mpox Infection: New York State, 2022 — supported the department’s ongoing guidance that two doses of JYNNEOS vaccine offers maximum protection against mpox.

State health officials said, last summer, as COVID-19 cases declined, mpox, which had been an extremely rare disease, broke out.

There were few biomedical tools with which to fight it, but JYNNEOS vaccine, an approved and licensed vaccine that had not been studied in a real-world setting of human-to-human spread, was available.

New York State was able to evaluate the effectiveness of the vaccine in near real-time as it was implemented, adding important data to inform future efforts at preventing mpox outbreaks.

The case-control study estimated the JYNNEOS vaccine effectiveness against mpox in New York residents outside of New York City using data from systematic surveillance reporting.

Researchers found that, while receiving one dose of the vaccine offered some protection (68.1 percent), getting the second dose had even higher protection (88.5 percent).

The findings support the approved use of JYNNEOS as a two-dose series for mpox prevention amid ongoing sexually related transmission of mpox and incorporating JYNNEOS vaccine into a broader program of sexual health services.

The CDC is urging clinicians to be on alert for new cases of mpox and to encourage vaccination for people at risk. Even suspected cases should be tested if the patient was previously vaccinated or had mpox, the agency said.

Because mpox is usually transmitted through close, sustained physical contact and has been almost exclusively associated with sexual contact in the current global outbreak, it is important to take a detailed sexual history for any patient with suspected mpox, the agency said.

Most patients with mpox have mild illnesses, although some, particularly those with advanced or untreated HIV infection may experience more severe illnesses and outcomes.