The Centers for Disease Control (hereafter referred to as the CDC) announced that in May 2026, two new confirmed cases of monkeypox were added, both unvaccinated against monkeypox. One case is a domestic infection: a man in his 40s from northern Taiwan who reported having unsafe sexual contact with an unspecified partner and, after noticing multiple blisters on his body, sought medical care, was tested and reported, and then confirmed. The other case is an imported infection: a man in his 20s from northern Taiwan who reported having unsafe sexual contact with an unspecified person in Thailand in April; after returning home, he developed genital blisters and rash on his hands and feet, sought medical care, was tested and reported, and was confirmed. Genetic sequencing identified the infection as belonging to clade I, subclade Ib (hereafter Ib type), marking the first detection of an Ib‑type virus strain in Taiwan since monkeypox became a legally notifiable disease in 2022; the remaining cases are infected with clade II virus strains.
Since 2022, a total of 144 countries have reported more than 179,000 confirmed monkeypox cases and 503 deaths worldwide, primarily distributed across the Americas and Africa. International surveillance and literature indicate that the Ib type has a slightly higher but comparable case‑fatality rate to the II type, and disease severity is related to the individual’s immune status; prevention and treatment measures are the same as for other cases. The global monkeypox outbreak continues; in March of this year, 48 countries/regions reported 1,235 new confirmed cases (including five deaths), with 70% concentrated in Africa. In Thailand, from 2022 to the end of January 2026, a total of 1,032 confirmed cases were reported, most of whom were men aged 30–39. In 2023, the Democratic Republic of Congo first identified an Ib‑type strain capable of sexual transmission, and from 2024 onward outbreaks occurred in several neighboring African countries. Since January 2024, 60 countries or regions worldwide have reported confirmed Ib‑type cases; outside Africa, countries such as Argentina, Denmark, Germany, Pakistan, Portugal, Spain, the United Kingdom, China, India, Thailand and Singapore have reported either their first cases or ongoing community transmission of the Ib type. Because the Ib virus continues to spread across borders, the risk is assessed as moderate for groups engaging in high‑risk behaviors, especially those without a regular sexual partner, while the transmission risk for the general public remains low.
The CDC reported that domestically, as of May 18 this year, 14 new confirmed monkeypox cases (12 domestic and 2 imported) have been added, all of whom are young to middle‑aged men aged 20–50. The cumulative total reaches 530 confirmed cases (493 domestic and 37 imported), with cases reported in the northern, central and southern regions. Epidemiological investigations found that all confirmed patients had engaged in unsafe sexual behavior, and nearly 90% had not received the monkeypox vaccine.
The CDC reminds that the incubation period of monkeypox can be as long as 21 days, and some cases can transmit the virus to others 1–4 days before symptom onset. Vaccination is currently the most effective preventive measure and can protect against both clade I and clade II virus strains. A total of 312 partner medical institutions nationwide provide publicly funded monkeypox vaccination services. Eligible individuals include those who have engaged in high‑risk behaviors in the past year (e.g., multiple sexual partners, sex workers, sexual activity in commercial venues, etc.), those with a history of sexually transmitted infections, or those whose sexual partners fall into any of the aforementioned categories; they should promptly complete the two‑dose publicly funded monkeypox vaccine series. After receiving two doses, protection against the monkeypox virus is about 90%; a single dose offers roughly 40%–80% protection. Moreover, vaccinated individuals who become infected tend to experience milder symptoms than unvaccinated persons. Information on publicly funded vaccination medical facilities can be found under the CDC’s website/Monkeypox Section/Monkeypox Vaccine/Monkeypox Vaccine Service Partner Medical Institutions ( https://gov.tw/3SG ) for reference. For those who do not qualify for publicly funded vaccination, individuals assessed by a physician as having a genuine exposure risk may receive the monkeypox vaccine at their own expense at any of the eight contracted travel medicine hospitals nationwide; related information can be found under the CDC’s website/International Travel and Health/Travel Medicine Outpatient Section.
The CDC again urges that people traveling to endemic areas or domestic high‑risk settings should practice self‑protection and avoid social venues where close contact with unspecified persons may occur. At the same time, please monitor your own or others’ symptoms to reduce exposure risk. If skin lesions appear—such as rashes, blisters, macules, papules, pustules, etc.—or if you experience fever, chills/shivering, headache, muscle aches, lymphadenopathy (e.g., around the ears, armpits, neck, or groin), you should wear a mask, seek medical attention promptly, and proactively inform the physician of travel history, exposure to high‑risk settings, or relevant contact history. For more information, visit the CDC’s website (https://www.cdc.gov.tw) or call the domestic toll‑free epidemic prevention hotline 1922 (or 0800-001922) for inquiries.
Source: Centers for Disease Control
Data compiled: Infection Control Office
