Mpox resurfaces in new countries: How to contain the outbreak?

A new mpox outbreak in Guinea-Bissau—a country that had never reported a case before—has brought the virus formerly known as monkeypox back into the headlines. So what has changed?

Since 2022, the world has recorded nearly 190,000 confirmed mpox cases across 145 countries. Previously, outbreaks were usually small and occurred only in a few African countries where the virus circulates in nature.

Mpox is an infectious disease that starts with flu-like symptoms such as fever, chills, and muscle aches, followed by a characteristic rash: bumps that turn into fluid-filled blisters and then crust over. The name “monkeypox” comes from the virus being first discovered in captive monkeys in 1958, but during the 2022 international outbreak, the World Health Organization (WHO) recommended renaming it to mpox to avoid stigmatizing and racist language.

The disease is endemic in many parts of Africa, with historical outbreaks often linked to eating infected wild animals. However, in recent years, the virus has spread beyond usual areas, with sustained human-to-human transmission chains. The U.S. Centers for Disease Control and Prevention (CDC) warned earlier this month that mpox could become endemic in the United States.

There are two main groups of mpox virus (clades). Clade I, formerly called the “Congo Basin clade,” and clade II, the “West African clade.” Clade II caused the 2022 global outbreak when changes emerged that allowed the virus to spread more efficiently through close contact, mainly sexual contact, with men who have sex with men being at highest risk.

In June 2024, researchers warned about a new variant of clade I in the Democratic Republic of the Congo (DRC), which also spreads more easily between people. This outbreak led to the public health emergency declared by WHO on August 14, 2024. Professor Michael Marks from the London School of Hygiene & Tropical Medicine said: “The emergence of mpox in several West African countries is predictable. Guinea and Sierra Leone have also recorded outbreaks in the past 12 months.”

The 2022 outbreak was declared a public health emergency in July that year and lifted in May 2023 after contact tracing and vaccination programs, with about 90,000 infections. The 2024 outbreak emergency was lifted in September 2025, not because the disease disappeared but because cases and deaths declined, and the situation was better controlled. However, global health officials could intervene again if genetic testing detects new variants or surveillance shows rapid spread, severe disease, or higher mortality.

In Guinea-Bissau, where no mpox case had been recorded before, UNICEF is concerned that among 46 suspected cases, 23 are children under 15, and most are under 4. Dr. Aula Abbara, senior lecturer at Imperial College London, explained: “Young children are at higher risk of severe disease and death than healthy adults.” However, she noted the overrepresentation of children in the data could be due to bias: “Families tend to take sick children to the clinic more than adults, especially in resource-limited areas like Guinea-Bissau.” Professor Marks added: “Children have close contact with parents and each other, living in crowded conditions, which increases transmission.” Confirmed cases have no clear links to each other, suggesting the virus may be circulating widely in the community with many undetected cases.

WHO recommends two types of vaccines that can be given to high-risk individuals or contacts of cases to prevent spread. However, Professor Marks pointed out: “The big challenge is that the best vaccine supply is concentrated in high-income countries, while the highest demand is in low-income countries.” A new global vaccine stockpile is expected to be deployed in the coming weeks, helping distribute vaccines faster and encouraging manufacturers to increase capacity. The antiviral drug tecovirimat was tested on patients with clade I mpox in the DRC and showed no better efficacy than placebo, though questions about benefits for immunocompromised patients remain open. The trial also showed that good supportive care significantly improves survival.

Dr. Abbara emphasized: “Vaccines are important, but outbreaks cannot be controlled by vaccines alone. Early detection, contact tracing, supportive care, and robust public health surveillance are absolutely essential.”