Over half of individuals diagnosed with mpox during the 2022 outbreak experienced persistent physical effects for more than a year. Concurrently, New York City has reported its first case of mpox caused by the Clade I strain, which is associated with more severe symptoms compared to the Clade II strain responsible for the 2022 global outbreak.
Long-Term Physical Effects of the 2022 Mpox Outbreak
A study conducted by researchers from the Centers for Disease Control and Prevention (CDC), Columbia University, and the University of Texas Health Science Center examined over 300 adults who contracted mpox during the 2022 outbreak. The findings indicate that 58% of participants, diagnosed between May 2022 and January 2023, reported experiencing ongoing physical effects between 11 and 18 months post-diagnosis.
The most frequently reported persistent issues included:
- Lesions in one or more body areas.
- Difficulty defecating or stool incontinence.
- Urinary hesitancy or incontinence.
- Reduced range of motion.
- Neurologic impairment.
- Fatigue.
The study also noted correlations between reported physical effects and socioeconomic factors, such as unstable housing, unemployment, disability, or food insecurity. These factors were associated with impacts on employment for affected individuals.
Furthermore, some patients reported experiencing stigma related to their diagnosis, including feeling hurt by others' reactions and hesitation from others to be near them.
The U.S. mpox outbreak began in May 2022, leading to over 30,000 cases, and was declared a public health emergency by both the CDC and the World Health Organization in August 2022.
Daily case numbers significantly decreased by late fall, a positive development attributed to behavioral changes and a widespread vaccination campaign. While the majority of cases occurred among men who have sex with men, health experts emphasized that anyone can contract the virus.
Identification of Mpox Clade I in New York City
The New York City Health Department has identified the city's first case of mpox caused by the Clade I strain of the virus. This patient recently traveled internationally, suggesting the case originated from outside the country. No local transmission of mpox Clade I has been identified in New York City, and the risk to local residents is currently considered low.
Clade I is a genetic group of the mpox virus associated with more severe symptoms and a potentially higher fatality rate. This contrasts with Clade II, which was responsible for the 2022 global outbreak and has a survival rate of over 99.9%. Clade I was also associated with an outbreak in the Democratic Republic of Congo and other regions in Africa in 2024.
Mpox Transmission, Symptoms, and Prevention
Mpox, formerly known as monkeypox, primarily spreads through direct skin-to-skin contact with an infected person, or contact with their rash, lesions, scabs, or body fluids. Prolonged contact with contaminated objects or fabrics carries a lower risk.
For Clade I mpox, transmission occurs through direct contact, including sexual contact and kissing, and via very close respiratory droplets. It is not known to spread over longer distances through respiratory routes.
Symptoms
Mpox symptoms typically appear one to three weeks after exposure. These can include:
- A rash, which may be painful and blistery, on various parts of the body.
- Fever, chills, exhaustion, muscle aches, and headache.
- Swollen lymph nodes.
- Respiratory symptoms.
In rare instances, mpox can lead to complications such as eye infections, severe rash, painful skin lesions, and neurological problems. Individuals who are immunocompromised or very young face the highest risk of severe infection.
Prevention and Treatment
The JYNNEOS vaccine is available and recommended for adults at high risk. The New York City Health Department advises at-risk New Yorkers to complete the two-dose mpox vaccine series.
The CDC recommends vaccination for gay, bisexual, and other men who have sex with men, aged 18 or older, who meet specific risk criteria. It is also recommended for individuals planning to travel to areas where Clade I mpox is circulating. Vaccination within 14 days is advised for those who may have been in close contact with an infected person, as it can reduce the chances of infection and lessen symptom severity. Individuals who have previously contracted mpox typically do not require vaccination.
Treatment for mpox primarily involves supportive care to manage symptoms. In severe cases, patients may be treated with TPOXX (tecovirimat), an antiviral medication used for infections caused by smallpox-related viruses.