Mpox cases in New York City have increased substantially since October 2023, mostly in people who haven’t been vaccinated or have only received one dose, the New York City Department of Health and Mental Hygiene (NYC Health) said in a May 3 health alert.

For most of 2023, the city averaged about 2 to 20 cases per month, but since October, cases have averaged 36 per month, with a peak of 51 in January. Of 256 cases reported since October, 73% were unvaccinated or had only received one dose, and 94% involved men who have sex with men. Most were Black and Hispanic men ages 25 to 44. Most cases were mild, and 10 people were hospitalized.

The health department urged healthcare providers to continue to encourage and offer vaccine to at-risk groups, especially those with HIV or other immunocompromising conditions, or to refer them to vaccination sites. Health officials acknowledged the transition of the Jynneos vaccine to the commercial market, noting that no-cost federally funded supplies will be available until early summer.

A reminder to be on the lookout for clade 1 cases

Also, it warned providers about the risk of the more severe clade 1 virus—currently fueling an ongoing severe outbreak in the Democratic Republic of the Congo (DRC)—to the United States. So far, the clade 1 outbreak strain hasn't been detected outside endemic countries in Africa. The global outbreak involves clade 2, which typically results in milder symptoms.

However, NYC Health urged providers to be alert for people who have mpox symptoms and a history of travel or epidemiologic links to the region, including the DRC.

• City officials in Long Beach, California, have declared a public health emergency to better allow the city to respond to a tuberculosis (TB) outbreak at a private facility housing at-risk populations, which has sickened 14 people so far, one fatally. Nine people have been hospitalized. The outbreak is occurring in a people who have barriers to healthcare, including those experiencing homelessness, housing insecurity, mental illness, substance use, and underlying health conditions. Officials said the risk to the general public is low. The investigation revealed that 170 people may have been exposed to TB, a number expected to grow, and health department staff are currently screening contacts.
• Spanish officials recently reported a local Crimean Congo hemorrhagic fever (CCHF) case, which involves an elderly man who has a tick bite and is isolated in the hospital in stable condition, the European Centre for Disease Prevention and Control (ECDC) said in its most recent weekly communicable disease threats report. Spain has now reported 13 CCHF cases since 2013, of which 5 were reported from the province where the man lives, Salamanca, in the western part of the country. Hyalomma ticks known to be the primary CCHF vector are present in southern and eastern Europe.
• France last week reported an imported Lassa fever case in a soldier who recently returned from abroad and was hospitalized in Ile-de-France, the ECDC also said in its weekly report. Investigators have identified the man's contacts, who are under monitoring. The report didn't note where the man was exposed to the virus. Over the past decade, European countries have reported seven imported Lassa fever cases, all from various African countries. Lassa fever typically spreads via contact with food or household items contaminated by rat droppings and urine, though human-to-human transmission can occur. The virus is endemic in a number of West African countries, and Nigeria is experiencing a large ongoing outbreak.